Yongmei Zheng, Beihang University, School of Chemistry and Environment, China
Abstract: In our works, inspired by water harvesting effect on surface of spider silk in mist, a series of functional fibers with unique wettability has been designed by various improved techniques such as dip-coating, fluid-coating, tilt-angle coating, electrospun and self-assembly, to combine the Rayleigh instability theory. The geometrically-engineered thin fibers display a strong water capturing ability than previously thought. The bead-on-string heterostructured fibers are capable of intelligently responding to environmental changes in humidity. Also a long-range gradient-step spindle-knotted fiber can be driven droplet directionally in a long range. An electrospun fiber at micro-level can be fabricated by the self-assembly wet-rebuilt process, thus the fiber displays strong hanging-droplet ability. The temperature or photo or roughness-responsive fibers can achieve a controlling on droplet driving in directions. The fibers with bead-on-string structures can be fabricated by the wet-assembly technique, which contribute to water collection in efficiency. These studies develop the novel materials for water harvesting engineering.
Acknowledgements: This work is supported by the National Natural Science Foundation of China (21234001, 21473007), the National Key Basic Research Program of China (2013CB933000)
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Andreas Kaidatzis, NCSR "Demokritos", Institute of Nanoscience and Nanotechnology, Greece
Abstract: A. Kaidatzis, G. Giannopoulos, V. Psycharis, and D. Niarchos Institute of Nanoscience and Nanotechnology, NCSR Demokritos, Athens, Greece L10-type magnetic compounds, including FeNi, possess promising technical magnetic properties of both high magnetization and large magnetocrystalline anisotropy energy and thus offer potential in replacing rare earth permanent magnets for magnetic sensing and permanent magnets applications. L10-FeNi was first discovered in an iron meteorite, formed by the long-range thermal diffusion of Fe and Ni in an asteroid’s core over a period of 4.6 billion years [1]. It was first artificially made in the L10-type structure with a stoichiometry of Fe50Ni50 by neutron bombardment [2] and estimated the order-disorder transformation temperature to be around 320 C, which is very low compared to the other L10-alloys. This results in very low diffusion of Fe and Ni atoms and makes the transformation extremely sluggish. This transformation can be enhanced either by the creation of vacancies, core-shell FeNi/L10-AuCu nanoparticles [3], or in the case of thin films by a strain mediated process [4]. Here we have employed a combinatorial sputtering process in order to study the conditions of fabricating the L10-FeNi phase and measure its magnetic properties. We have used Si(100) 100 mm wafers as substrates and deposited multilayers of the following type: Si/Cr(10 nm)/Cu3Au(70 nm)/combi-CuAuNi/NiFe(40 nm), where combi-CuAuNi is a compositional spread layer of various stoichiometries deposited using combinatorial sputtering. The rest of the layers have homogeneous composition and thickness. The final deposition of FeNi was done at 2000C by co-sputtering Fe and Ni to a stoichiometry of 50/50 at%. We perform magnetic properties mapping of the multilayer by means of high-throughput polar Kerr effect magnetometry and we find that the coercivity increases from approximately 0.3 kOe to 1 kOe as the Au content of the combinatorial interlayer decreases. A thorough structural and magnetic properties study will be presented.
Acknowledgements: Funding from the E.C. is acknowledged (Grant No. 318144 and 280670)
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Stavros Pissadakis, Institute of Electronic Structure and Laser, Foundation for Research and Technology, Greece
Abstract: A review on our work on magneto-fluidic and magneto-viscosity based devices developed in standard and microstructured optical fibres, using ferrofluids as actuating elements, will be given. The examples presented will refer to photonic devices developed in microstructures optical fibres infiltrated using ferrofluids for the development of compact and directional magnetometers; and to ferrofluid out-cladded sensing and light routing photonic devices realised in standard and tapered optical fibres.
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Ivan Volkov, Moscow Institute of Physics and Technology, Laboratory for technologies of printing of functional microstructures, Russian Federation
Abstract: The conductive nanofibrous composite incorporating single-walled carbon nanotubes (CNTs) and an organic material was fabricated in the porous glass microfiber matrix by a filtration of water based suspensions followed by air drying. According to the scanning electron microscopy data, the composite nanofibers (mean diameter ~ 30 nm) are wrapped around the majority of glass microfibers and in particular areas they form branched network linked to glass microfibers. The contributions of intra-CNT and inter-CNT conduction mechanisms in thus functionalized microfiber paper were evaluated from the results of impedance spectroscopy. The crossover between these mechanisms is observed at a content of CNTs in the functionalized paper of about 0.1 wt. %; the corresponding dc conductivity is of the order of 0.2 S/m. The investigated materials hold promise for low-power gas sensors and as electromagnetic shielding materials.
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Mustafa Erkovan, Sakarya University, Department of Nanoscience and Nanoengineering, Turkey
Erdem Şennik, Nigde University, Nanotechnology Application and Research Center, Turkey
Şeyma Ürdem, Sakarya University, Department of Nanoscience and Nanoengineering, Sakarya, Turkey
Necmettin Kılınç, Nigde University, Department of Mechatronics Engineering, Turkey
Abstract: This work presents hydrogen (H2) sensing properties of platinum (Pt) and platinum-silver (PtAg) alloy thin films deposited on glass substrate by magnetron sputter deposition. The Pt thin films were prepared on a glass slide. The H2 sensing properties of Pt sensors were examined in the concentration range of 0.1 % - 1 % H2 under a dry air flow. On the other hand, Pt0.95Ag0.05, Pt0.90Ag0.10 and Pt0.80Ag0.20 alloy thin films were fabricated in the concentration range of 25 ppm and 1000 ppm H2. Thus, the best working performances of Pt and PtAg thin film sensor were determined. Hydrogen (H2) is a renewable energy source and has many applications such as chemical production, fuel cell technology, fuel for cars, etc. H2 is colorless, odorless, tasteless, flammable and explosive between 4% -75% concentrations in any ambient and cannot be detected by human senses. The detection of H2 in a wide range concentration is crucial for leak detection, safety issue and real time quantitative analysis [1-5]. So, it requires hydrogen sensors that are accurate, fast and working in a wide hydrogen concentration. The research on H2 gas sensor has been focused on to improve the sensor parameters such as sensitivity, reversibility, operation temperature, power consumption. There are a limited numbers of researches on hydrogen sensing properties of Pt. Besides the sensing mechanism of Pt-based resistive hydrogen sensor is not fully understood. So, the investigation in this work will overcome in this regard and will make contributions in hydrogen sensor applications. This study will show that H2 sensing properties are investigated depending on film thickness, temperature and concentration. Thus it will provide to understand the sensing mechanism of Pt-based sensors. Pt and PtAg alloy thin films were fabricated by magnetron sputtering system on microscope glass slides. Besides co-sputtering was used to deposit PtAg thin films. RF power supply was used for Pt sputtering while Ag sputtering was carried out with DC power supply. All the sputtering procesess were carried on at 5 mTorr of Argon ambient. The structural characterization of the Pt and PtAg thin films were characterized by X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. In order to measure resistance measurements of the sensors, four Au pad electrodes were coated on the samples by using thermal evaporator. The changes of resistance for each Pt thin films were recorded by means of a four point-probe, which connected to a multimeter. The structural characterizations of Pt thin films were investigated in our previous study [6]. 15 nm PtAg films were analyzed between 0o and 90o with the step of 0.05o. The results for Pt thin film sensor showed that the resistance is directly proportional with temperature, and inversely proportional with the thickness of Pt thin film. The sensitivities of Pt sensors decreased with enhancing temperature. The results revealed that the Pt thin film with 2 nm thickness exhibited the best sensing performance to H2 at 30 °C under dry air. Temperature dependent changes of the resistances for Pt0.95Ag0.05, Pt0.90Ag0.10 and Pt0.80Ag0.20 thin film sensors were increased with increasing the temperature from 30 °C to 200 °C. Pt0.80Ag0.20 thin film sensor showed the best sensitivity at 150 oC under dry air. As a result, H2 sensitivity of Pt thin film sensors has higher than that of PtAg sensors. Pt sensor works at room temperature while PtAg sensor needs for high temperatures to work well. Improvements in working performance of PtAg sensor would depend on developing the experimental fabrication process of PtAg thin films and need some researches to improve the sensing performance of PtAg alloy films. The working performance of Pt sensor demonstrated that it can be used in desired application areas for hydrogen gas sensor technologies. On the other hand, the promising results presented in this study for hydrogen detection by using Pt as a sensing material. References [1] J.S. Noh, J.M. Lee, and W. Lee (2011): Low-Dimensional Palladium Nanostructures for Fast and Reliable Hydrogen Gas Detection. Sensors 11, 825-851. [2] J. Lee, W. Shim, J.S. Noh, and W. Lee (2012): Design Rules for Nanogap-Based Hydrogen Gas Sensors. Chemphyschem 13, 1395-1403. [3] N. Kilinc (2013): Resistive Hydrogen Sensors Based on Nanostructured Metals and Metal Alloys. Nanoscience and Nanotechnology Letters 5, 825-841. [4] T. Hubert, L. Boon-Brett, G. Black, and U. Banach (2011): Hydrogen sensors - A review. Sensors and Actuators B-Chemical 157 329-352. [5] S.K. Arya, S. Krishnan, H. Silva, S. Jean, and S. Bhansali (2012): Advances in materials for room temperature hydrogen sensors. Analyst 137, 2743-2756. [6] E Şennik, Ş Ürdem, M Erkovan, N Kılınç (2016): Sputtered platinum thin films for resistive hydrogen sensor application. Materials Letters 177 104–107.
Acknowledgements: This study was supported by TUBITAK under the Grant No. 114M853.
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IBRAHIM GAIDAN, SIRTE UNIVERSITY, Electrical & Electronics Enginering, Libyan Arab Jamahiriya
Abstract: Four sensors were fabricated and tested. Three sensors were made from 75/25, 50/50 and 25/75 mol. % of Fe2O3/MnO2 while the fourth sensor was made from PVB polymer. These sensors were tested to detect different gases and the results was reported in our previous study [1]. In this study the conduction mechanism (Current – Voltage Characteristics and Frequency Measurements) of these sensors was investigated and reported. For I-V measurements an electronic circuit was built and used. The power supply voltage, increased with a step size of 1 volt (3- 30 volts) and the current and voltage were recorded. The relationship between I -V and log I - V 1/2 for each film was plotted. The frequency related measurements were carried out using impedance analyser HP 4277 A LCZ- meter. The results show that the actual permittivity values of the thick films layers (measured using an LCZ bridge) are most closely correlated to Poole- Frenkel effect. These values are close to the values reported by other researchers using different oxide ratios [2, 3]. 1. Arshak, K. and I. Gaidan, Development of an array of polymer/MnO2/Fe2O3 mixtures for use in gas sensing applications. Sensors and Actuators B: Chemical, 2006. 118(1–2): p. 386-392. 2. Collins, D.G., The design and Development of Thick Film Materials for Strain Sensing Applications. ph.D thesis, 1995. 3. Ramadhan, F.A.S.A., ph.D thesis, 1985: p. 97-115
Acknowledgements: Conduction Mechanism (Current – Voltage Characteristics and Frequency Measurements) of Gas Sensors
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Georges Dubourg, BioSense Institute, University of Novi Sad, Serbia
Abstract: Humidity sensors find applications from semiconductor manufacturing to soil moisture monitoring or in food industry and are generally fabricated on ceramic and silicon substrates. Nevertheless, recent advancements in the field of printed electronics show increased potential in substitution of the rigid substrates by flexible substrates, due to their low cost and easy fabrication processing. A key parameter is the deposition of sensing materials that can be adapted to the printed electronics technological processes, such as printing methods. In this work, we present a novel, flexible and miniaturized humidity sensor using screen-printed TiO2 Humidity sensors find applications from semiconductor manufacturing to soil moisture monitoring or in food industry and are generally fabricated on ceramic and silicon substrates. Nevertheless, recent advancements in the field of printed electronics show increased potential in substitution of the rigid substrates by flexible substrates, due to their low cost and easy fabrication processing. A key parameter is the deposition of sensing materials that can be adapted to the printed electronics technological processes, such as printing methods. In this work, we present a novel, flexible and miniaturized humidity sensor using screen-printed TiO2 nanoparticles as the active layer. The proposed sensor operates in room-temperature conditions and exhibits high sensitivities to changes in realtive humidity. The humidity sensor consists of a TiO2 -based sensitive nanomaterial on top of interdigitated electrodes (IDEs) patterned on flexible substrate. The I-V characteristic of the sensor shows a good linearity and resistance measurements confirm the water vapour’s absorption on the sensitive layer, showing a three-order of magnitude variation on the resistance, in the range of 35 to 95% relative humidity, exhibiting a relatively fast response and recovery time without the need of any refreshing method. These results suggest that screen-printed TiO2 nanoparticles are sensitive to humidity changes. Additionally, a low-temperature process are proposed, that paves the way to large-scale fabrication of printed sensors on flexible substrate.
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Mojtaba Jahangiri, K. N. Toosi University of Technology, Electrical Engineeing Department, Iran (Islamic Republic of)
Ehsan Yousefiazari, K. N. Toosi University of Technology, Electrical Engineeing Department, Iran (Islamic Republic of)
Milad Ghalamboran, K. N. Toosi University of Technology, Faculty of electrical engineering, Iran (Islamic Republic of)
Abstract: Pressure sensor is one of the most commonly used sensors in the research laboratories and industries. These are generally categorized in three different classes of absolute pressure sensors, gauge pressure sensors, and differential pressure sensors. In this paper, we fabricate and assess the pressure sensitivity of the current vs. voltage diagrams in a graphite/ZnO/graphite structure. Zinc oxide layers are deposited on highly oriented pyrolytic graphite (HOPG) substrates by sputtering a zinc target under oxygen plasma. The top electrode is also a slice of HOPG which is placed on the ZnO layer and connected to the outside electronic circuits. By recording the I-V characteristics of the device under different forces applied to the top HOPG electrode, the pressure sensitivity is demonstrated; at the optimum biasing voltage, the device current changes 20 times upon changing the pressure level on the top electrode by 50%. Repeatability and reproducibility of the observed effect is studied on the same and different samples. All the materials used for the fabrication of this pressure sensor are biocompatible, the fabricated device is anticipated to find potential applications in biomedical engineering.
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samia gamouh, Laboratory of Semiconductor and Hyper frequency, University of Mentouri Constantine, ALGERIA, Electronics, Algeria
Abstract: In this paper, a theoretical study of biosensor based on microwave split-ring resonators (SRRs) excited by microstrip transmission line is presented. The sensor consists of a microstrip line loaded with circular SRRs on both sides .The operating principle of these biosensor is based on the interaction of the electromagnetic near-field generated by the sensor with the samples under investigation. The SRR can be considered as an RLC resonator circuit whose frequency response is very sensitive to the changes in capacitive and inductive effects . At the resonance frequency, the resonator develops an intense and localized electric across the split, enabling sensitive detection of extremely small amounts of simples. The detection method is based on the principle of the shift of the resonance frequency as a function of the relative permittivity of the loading sample. In order to enhance sensing performance of the device, a new split gap are adding in each rings, that will provide a strong and localized field enhancement in the selected area, increasing the high electric field region. The shift of the resonance frequency in the presence of a sample material is characterized by multiple resonant frequencies, upon introduction of several samples with different dielectric value. The metamaterial resonator is tested through proper full-wave numerical simulation ( HFSS ) based on the finite element method (FEM).
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Jianqiao Liu, Dalian Maritime University, College of Information Science and Technology, China
Yuncong Geng, University of Electronic Science and Technology of China, School of Computer Science and Engineering, China
Guohua Jin, Dalian Maritime University, College of Information Science and Technology, China
Zhaoxia Zhai, Dalian Maritime University, College of Information Science and Technology, China
Abstract: The roles of depletion layer width in semiconductor gas sensors are quantitatively discussed based on the model of gradient-distributed oxygen vacancies. Several literatures are employed to provide experimental basis of the relationship between depletion layer width and gas sensing characteristics of semiconductor devices. Four series of gas sensors are illustrated and their depletion layer widths are controlled by three different techniques, such as controlling of the dopant amount, sintering in various procedures and usage of various dopants. The model shows a good applicability in analyzing the roles of the depletion layer width in semiconductor gas sensors, especially when the width of the depletion layer is controlled by the doping amount of the foreign elements.
Acknowledgements: This work is financially supported by the Liaoning Natural Science Foundation (Grant No. 2015020019) and the Fundamental Research Funds for the Central Universities.
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Denis Sokol, Vilnius University, Department of Inorganic Chemistry, Lithuania
Abstract: Layered double hydroxides (LDHs) or hydrotalcite type compounds have general formula of [MII1-x MIIIx(OH)2]x+(Am- )x/m]·nH2O. The most representative hydrotalcite mineral is Mg6Al2(OH)16.CO3.4H2O. However, magnesium could be replaced by Ca2+ ions. This compound is included in a subgroup known as hydrocalumnite group with most representative mineral - Ca2Al(OH)6.Cl 3H2O [1-3]. Mixed metal oxides obtained after calcination LDH or hydrocalumite group minerals at elevated temperatures show interesting acid-based properties. Therefore, these calcination products could be successfully used as catalyst in organic synthesis [4] and as different gas sensors. For that reason we decided to modify Ca/Al layered double hydroxide with different metal oxides and compare their properties before and after modification. In this study, the Ca/Al layered double hydroxides were synthesized via novel alkoxy-free sol-gel and co-precipitation methods. Metal oxide anions (CrO42-, MnO42-, MoO42-, VO31-) have been introduced to Ca/Al hydrocalumnite interlayer by two different methods: by direct formation of LDH by co-precipitation when sodium nitrate or sodium carbonate is changed by appropriate metal oxide salts and by so called “soaking” method - when Ca/Alco-pr or Ca/Alsol-gel HCT compounds are thermal treated and obtained mixed metal oxides are reconstructed in metal oxide salt aqueous solution back to layered structure, using LDH so called “memory effect”. The heat treated mixed metal oxide (MMO) were used as a catalyst. For that reason, all obtained Ca/Al HCT compounds have been calcinated and their mixed metal oxides have been obtained [4,5]. By tuning the ratio of metal oxide salts, the solvent composition, reaction pH and heat treatment temperature, the Ca/Alco-pr.CO3, Ca/Al sol-gel.CO3 and their modified Ca/Al (CrO42-, MnO42-, MoO42-, VO31-) layered double hydroxides and appropriate MMO were successfully synthesized. The influence of mixed metal oxide salt concentration, calcination and reconstruction temperature and reconstruction pH on the phase composition and catalytical properties of final product is discussed. All samples synthesized by two synthetic techniques were analyzed and characterized using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX) and thermogravimetric (TG) analysis.
Acknowledgements: This work was supported by project TUMOCS. This project received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 645660.
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Young-A Son, Chungnam National University, Advanced Organic Materials Engineering, Korea, Republic of
Abstract: Ick-Jin Kim, Ramalingam Manivannan, Jeamyeng Jeong, Changkyeom Kim, Kyo-Sun Ku, Wooram Oh, Young-A Son* Chungnam National University, Dept. of Advanced Organic Materials Engineering, Yuseong, 34134, Republic of Korea In this work, fluoran molecules have been designed and synthesized, and their reversible thermo-dependent properties have been monitored and investigated. This result demonstrates interesting thermochromic reversibility of the fluoran molecules. Furthermore, three-component mixtures that comprise of fluorans, a sensing color developer, and a low melting solvent were used to examine the thermo-related chromic behaviosr with sturdy heating and cooling rates. Thermo-dependent chromic properties of the fluoran molecules were studied in details using UV-Vis, reflectance and FT-IR spectroscopic techniques.
Acknowledgements: This study was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (Grant no. 2015063131).
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Badi Ridha, Centre for Research in Industrial Technologies CRTI, ex - CSC, Metallurgy and Mechanical Division, Algeria
Abstract: In this work, the microstructure evolution and the mechanical behavior of WC-Co / 1020 steel joint obtained by oxyacetylene and tungsten Inert Gas (TIG) brazing process are investigated. The maximum peak temperature induced by TIG process and the introduction of shielding gas causes a remarkable inter-diffusion at WC-Co/braze interface. The diffusion of Co Towards the braze in the interface obtained by TIG process is greater compared with the oxyacetylene ones. On the other side, a short range diffusion of Ni towards the WC-Co is observed. This phenomenon leads to create a new zone devoid in Co elements with high WC particle concentration at WC-Co/braze interface using TIG brazing process. The mechanical behavior is carried out through shear and micro-hardness test, they show that the presence of the new zone concentrated in WC particles beside the hard metal, makes the joint less strong than the one obtained by the oxyacetylene brazing, despite the inter-diffusion of Co and Ni elements in the interface. However, special shear test (SST) reveals that the joint made by the TIG process is resistant as much as the oxyacetylene brazing one.
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Sébastien Pecqueur, CNRS-IEMN, NCM, France
Stéphane Lenfant, CNRS-IEMN, , France
David Guérin, CNRS-IEMN, , France
Fabien Alibart, CNRS-IEMN, , France
Dominique Vuillaume, CNRS-IEMN, , France
Abstract: We report on hydrazine-sensing organic electrochemical transistors (OECTs) with a design consisting in concentric annular electrodes. The design engineering of these OECTs was motivated by the great potential of using OECT sensing arrays in fields such as bioelectronics. In this work, PEDOT:PSS-based OECTs have been studied as aqueous sensors, specifically sensitive to the lethal hydrazine molecule. These amperometric sensors have many relevant features for the development of hydrazine sensors, such as a sensitivity down to 10-5 M of hydrazine in water, an order of magnitude higher selectivity for hydrazine than for 9 other water soluble common analytes, the capability to recover entirely its base signal after water flushing and a very low voltage operation. The specificity for hydrazine to be sensed by our OECTs is caused by its catalytic oxidation at the gate electrode and enables increasing the output current modulation of the devices. This has permitted the device-geometry study of the whole series of 80 micrometric OECT devices with sub-20-nm PEDOT:PSS layers, channel lengths down to 1 µm and a specific device geometry of coplanar and concentric electrodes. The numerous geometries unravel new aspects of the OECT mechanisms governing the electrochemical sensing behaviours of the device, more particularly the effect of the contacts which are inherent at the micro-scale. By lowering the device cross-talking, micrometric gate-integrated radial OECTs shall contribute to the diminishing of the readout invasiveness and therefore promotes further the development of OECT biosensors.
Acknowledgements: The authors wish to thank the European Commission under the H2020-FETOPEN-2014-2015-RIA program, RECORD-IT project GA 664786, and the French National Nanofabrication Network RENATECH for financial supports. We thank also the IEMN cleanroom staff of their advices and support.
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Vasily Lavrentiev, Nuclear Physics Institute ASCR, Neutron Physics Department, Czech Republic
Alexandr Stupakov, Institute of Physics ASCR, , Czech Republic
Inna Lavrentieva, Nuclear Physics Institute ASCR, , Czech Republic
Mykhaylo Motylenko, Institute of Materials Science, Freiberg University of Technology, , Germany
Michael Barchuk, Institute of Materials Science, Freiberg University of Technology, , Germany
Abstract: Discovery of superconductivity in alkali fullerides generates great interest to the metal-fullerene materials and to the methods of their fabrication [1]. As a result of such an interest, the remarkable Co-C60 composite nanostructures with attractive spin-transfer and magnetic properties were established [2, 3]. Here we demonstrate the effect of air exposure on nanostructure and magnetic properties of the self-assembled CoxC60 nanocomposites fabricated by simultaneous deposition. The CoxC60 mixture films (with x<40) were deposited on Si(100) substrates at room temperature in high vacuum. Before the analytical experiments the mixture films were exposed to air for 1 hour. Rutherford backscattering spectroscopy analysis revealed appearance of oxygen in the air-exposed mixture films. We found that amount of oxygen in the CoxC60 films depends on the Co concentration x. It greatly increases in the films with x>2. Study of the films by transmission electron microscopy (TEM), atomic force microscopy and SQUID magnetometry revealed formation of composite nanostructure in the CoxC60 film with x>2, were small Co clusters (few nm in size) are distributed in the C60-based matrix. Structural analysis performed with TEM and X-ray diffraction shows that oxygen is mainly retained in the CoO layer formed on the surface of Co clusters during air exposure of the films. Detailed analysis of the film magnetization carried out at different temperatures T (5
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Faramarz Hossein-Babaei, K. N. Toosi University of Technology, Electrical Engineering Department, Afghanistan
Navid Alaei-sheini, K. N. Tossi university of technology , Electrical Engineering Department, Iran (Islamic Republic of)
Abstract: Intensely studied memristive devices have M’/MO/M’’ structures, wherein MO is a nanometer-sized metal oxide crystallite sandwiched between the M’ and M’’ metal electrodes. The most widely used oxide for this purpose is TiO2 and the electrodes are of noble metals such as platinum, silver, and gold. The memristive features of the device is believed to originate from the motion of the ionized oxygen vacancies within the oxide crystal. The operation of the device is further complicated by the motion of the mobile cations originating from the metal electrodes. The complexity of the device performance increases further when the noble metal electrodes form Schottky barriers at their junctions with TiO2, as the conduction takes place through these energy barriers. In a very recent publication, the authors have shown that, owing to ohmicity of the Ti/TiO2 junctions, electronic observations on the devices with Ti/TiO2/Ti structure can be easier to model [FHB and NAS, Scientific Reports, srep29624, 2016]. The presented model clarified that in a Ti/poly-TiO2/Ti structure, the ionic motion and the electronic conduction take place on the TiO2 grain surfaces and grain boundaries rather than the grain interiors. Here, we show that the suggested model has important implication for chemical sensor design and fabrication.
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Shiva Mohammad-Yousefi, Shahed University, Electrical Engineering , Iran, Islamic Republic Of
Saeideh Rahbarpour, Shahed university, Electrical engineering, Iran (Islamic Republic of)
Hassan Ghafoorifard, Amirkabir University of Technology, Electrical Engineering , Iran, Islamic Republic Of
Abstract: The effect of Pd and Au additives on gas sensing properties of SnO2 was investigated. SnO2 pallets were fabricated and sintered at 900 °C for 90 minutes. Several nanometer layers of Pd and Au were deposited on separate SnO2 pallets and were intentionally dispersed into the SnO2 pallets by long heat treatment (400 °C for 1 Day). All metal loaded samples showed significant enhancement in response level and optimum operating temperature compare to pure SnO2 gas sensors. The amount of enhancement was strongly dependent on the material and the thickness of deposited metal layer. Studying butanol response showed that increasing the thickness of metal causes the response level to increase. Further thickness increase caused contrary effect and decreased the performance of sensors. Best results were achieved at 10 nm-thick Au and 7 nm-thick Pd. Generally, Pd-SnO2 samples demonstrated better performance than Au-SnO2 ones, however, Au-SnO2 samples were proved to be good candidate to sense reducing gases with lower hydrogen atoms in their formula. Given experimental results were also good evidence of chemical activity of gold and simply confirms the relation between chemical activity and gold particle size. Results were qualitatively described by gas diffusion theory and surface reactions take place on metal particles.
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Michael Kompitsas, NHRF, TPCI/LATA, Greece
Abstract: M. Dhaouadi, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cédria, Hammam-Lif, Tunisie. M. Jlassi, Ecole supérieure des sciences et technologies du design, Université de la Manouba, Tunisie. I. Sta, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cédria, Hammam-Lif, Tunisie. M. Hajji, Institut Supérieur d’Electronique et de Communication de Sfax, Université de Sfax, Sfax, Tunisie G. Petropoulou, National Hellenic Research Foundation, Athens, Greece G. Mousdis, National Hellenic Research Foundation, Athens, Greece M. Kompitsas, National Hellenic Research Foundation, Athens, Greece W. Dimassi, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cédria, Hammam-Lif, Tunisie. Abstract:Copper oxide thin films were prepared by the sol–gel and the spin coating technique onto glass substrates using methoxy ethanol solutions of 0.1, 0.3 and 0.5 M Cu(CH3COOH)2 as precursors. The prepared films were annealed at 550° C and their physical properties were studied as a function of the concentration of the precursor solution. The structural properties of the prepared CuO films were characterized by X-ray diffraction (XRD) and Raman. The XRD analysis revealed single phase monoclinic structure whose nanoparticles had sizes in the 21-26 nm range and a preferred grain orientation in the (002) direction. All Raman spectrometry revealed the existence of the CuO phase. Optical transmission was studied by UV–vis spectrophotometer, which showed a decrease in transmission with increasing concentrations. A shift in the optical band gap from 3.48 eV to 2.01 eV has been observed. The resistivity value increased from 0.84 x 10² Ωcm to 1.24 x 10² Ωcm with the precursor molar concentration. Moreover, photoluminescence spectra also confirmed the single-phase formation of CuO thin films.
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Michael Kompitsas, NHRF, TPCI/LATA, Greece
Abstract: K.Sahbeni, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cedria,Tunisia M.Jlassi, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cedria,Tunisia I.Sta, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cedria,Tunisia M.Kandyla, National Hellenic Research Foundation. Athens, Greece M. Kompitsas, National Hellenic Research Foundation. Athens, Greece W.Dimessi, Centre de Recherche et des Technologies de l’Energie, Technopole de Borj-Cedria,Tunisia Abstract Precursors of the titanium oxide and zinc oxide were prepared by sol-gel method and nanocomposite titanium oxide/zinc oxide (TiO2/ZnO) thin films were deposited on glass substrate using spin-coating techniques. The physical properties of the prepared films were studied by varying the composition of the nanocomposite precursors. The structural properties of the nano-composite TiO2/ZnO thin film were determined by X-Ray Diffraction (XRD) and Raman Spectrometry. The XRD analysis revealed the appearance of new plane diffraction by increasing the amount of ZnO into the TiO2 precursor. The Raman spectra were in agreement with the XRD results. The optical properties of the films were characterized by UV-visible spectrophotometer which showed that the films were highly transparent in the visible region, but were slightly influenced by the different ZnO/TiO2 ratio in the compound. The electrical properties were measured by the 4 points measurement method. An increasing in the resistivity with adding ZnO in TiO2 matrix has been observed
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Michael Kompitsas, NHRF, TPCI/LATA, Greece
Abstract: I. Ben Miled, Centre de Recherche et des Technologies de l’Energie, Technopole de BorjCédria, Hammam-Lif, Tunisie. M. Jlassi, Institut supérieur des beaux-arts de Tunis, Université de Tunis, Tunisie. I. Sta, Centre de Recherche et des Technologies de l’Energie, Technopole de BorjCédria, Hammam-Lif, Tunisie. M. Hajji, Institut Supérieur d’Electronique et de Communication de Sfax, Université de Sfax, Sfax, Tunisie. G. Petropoulou, National Hellenic Research Foundation, Athens, Greece. G. Mousdis, National Hellenic Research Foundation, Athens, Greece. M. Kompitsas, National Hellenic Research Foundation, Athens, Greece. H. Ezzaouia, Centre de Recherche et des Technologies de l’Energie, Technopole de BorjCédria, Hammam-Lif, Tunisie. Abstract: CdO thin films have been prepared by the sol-gel method and the spin coating technique. The films have been annealed at 350, 450, 550° C for 1 h. The effect of annealing temperature on the structural, optical and electrical properties of the films has been investigated. The XRD analysis revealed that the films are polycrystalline with (111) preferential orientation. The optical properties of the films were characterized by UV–Visible spectrophotometry. The transmission of the films is increased up to 75% with decreasing of the annealing temperature. The optical band gap decreased from 2.59 to 2.32 eV with increasing of annealing temperature from 350 to 550° C. Electrical measurements showed that the resistivity decreased with increasing annealing temperature. Hall-effect measurements revealed that all thin films were n-type.
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Seyed Mohsen Hosseini-Golgoo, University of Guilan, Electrical Engineering Department, Iran, Islamic Republic Of
Fatemeh Salimi, University of Guilan, Electrical Engineering Department, Iran, Islamic Republic Of
Alireza Saberkari, University of Guilan, Electrical Engineering Department, Iran, Islamic Republic Of
Saeideh Rahbarpour, Shahed university, Electrical engineering, Iran (Islamic Republic of)
Abstract: In the present work the feature extraction of transient response of a resistive gas sensor under temperature cycling, temperature transient, and temperature combination methods were compared. So, the heater were stimulated by three pulse (cycling), ramp (transient) and staircase (combination) waveforms. The period or duration of all waves was equal to 40 s. Methanol, ethanol, 1-propanol, 1-butanol, toluene and acetone each at 11 different concentration levels in the range of 100 to 2000 ppm were used as the target gases. The utilized sensor was TGS-813 that made by Figaro Company. Recorded results were studied and heuristic features such as peak, rise time, slope and curvature of recorded responses were extracted for each heater waveform. Results showed that although application of this feature extraction method to all waveforms led to gas diagnoses, best results were achieved in the case of staircase waveform. The combination waveform had enough information to separate all examined target gases.
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Mohamed Abouelatta, Faculty of Engineering- Ain Shams University, Electronics & Communications Engineering, Egypt
Abstract: The main idea of this paper is to investigate the electrical performance of a proposed 3D Cadmium Telluride (CdTe) detector structure. The simulation of the 3D structure is carried out using SILVACO TCAD. The obtained results are used as a proof of concept for investigating 3D detectors in different operating conditions. The collection time of the proposed structure is about 0.04 ns at 15 V. The fast and hard detection of the structure makes it suitable for stopping power up to 3 TeV, which meets the future applications of SLHC. The very low leakage current, which is about 16 pA at 16 V, is attractive for most future applications, which allows us to apply higher bias voltage than was possible with previous traditional 2D CdTe detectors. Based on this study, the 3D CdTe technology is recommended for future high-energy physics and medical applications.
Acknowledgements: This work was supported by Intelligent Fast Interconnected and Efficient Devices for Frontier Exploitation in Research and Industry (INFIERI) Program.
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Maria Richetta, University of Rome Tor Vergata, Industrial Engineering Department, Italy
Girolamo Costanza, University of Rome "Tor Vergata", Industrial Engineering Dpt, Italy
Roberto Montanari, University of Rome Tor Vergata, , Italy
Maria Elisa Tata, University of Rome Tor Vergata, , Italy
Alessandra Varone, University of Rome Tor Vergata, Industrial Engineering Department, Italy
Abstract: The microstructural stability is one of the utmost important requirements for metallic materials in engineering applications, in particular at high temperature. Mechanical Spectroscopy (MS), i.e. internal friction (IF) and dynamic modulus measurements, is a technique that permits to monitor in real-time and with high sensitivity the formation of cracks and the evolution of lattice defects in metals under different mechanical stress and thermal conditions. This paper describes and discusses some applications of the MS technique to different metals and alloys: Ni base superalloys, nanostructured FeMo alloys produced via SPS sintering, Ti6Al4V composites reinforced by SiC fibres and AISI 304 stainless steel.
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Bouzid MAAMACHE, Research Center in Industrial Technologies (CRTI), Mechanic and Metallurgy, Algeria
Bilel CHENITI, Research Center in Industrial Technologies (CRTI), Mechanic and Metallurgy, Algeria
Youcef YAHMI, Research Center in Industrial Technologies (CRTI), Mechanic and Metallurgy, Algeria
Abstract: The aim of this work is to study the influence of successive weld repairs on the microstructure, the mechanical properties and the corrosion resistance of the weldment of an HSLA X70steel. Detailed microstructural examination combined to grain size measurement showed that beyond the second weld repair, the microstructure of the HAZ undergoes significant change in the grain morphology and grain growth. Consequently, a loss of the mechanical properties namely the yield strength and the toughness with the number of the weld repairs was recorded. Potentiodynamic polarization tests of different repair weld were evaluated in 0.8% HCl solution. Beyond the second weld repair the corrosion resistance decrease due to the formation of martensite-austenite (M-A) and bainitic structures.
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Sacia Djeroud, université 8 mai 1945 guelma, materials science, Algeria
Abstract: We present in this paper the results of a first-principles study of structural and electronic properties of Cd1-xVxTe with x = 0.03125, using the full-potential linearized augmented plane wave plus local orbital (FP-LAPW+lo) method based on the spin-polarized density functional theory. For the exchange correlation potential we used the generalized gradient approximation. From the minimization of the total energy, we determined the equilibrium structural parameters. The calculated band structures reveal that V-doped CdTe in the zinc blende phase is a half metallic ferromagnetic material. The magnetic properties of Cd0.96875V0.03125Te are discussed.
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Andreas Kaidatzis, NCSR "Demokritos", Institute of Nanoscience and Nanotechnology, Greece
Abstract: Andreas Kaidatzis, Vassilis Psycharis, Dimitrios Niarchos Institute of Nanoscience and Nanotechnology, NCSR Demokritos, Athens, Greece María Ujué González Sagardoy, José Miguel García Martín Instituto de Microelectronica de Madrid, CNM-CSIC, Tres Cantos, Madrid, Spain Paper is a low-cost, foldable, lightweight material that can be fabricated at thin sheets, easily stackable, stored and transported; it is currently being investigated as substrate for one-cent sensors fabrication [1] and for foldable electronics applications [2]. In this work, sputtered metal films on printer paper are studied for use as foldable and low-cost templates [3]. Two kinds of commercially available paper sheets have been used: i) uncoated 80 g/m2 printer paper, and ii) coated 200 g/m2 art paper with single-side glossy finish (the one used for deposition). Ultra-high vacuum DC magnetron sputtering was employed for depositing Au or Ag thin films; their surface morphology, crystal structure, and resistivity have been studied by optical and atomic force microscopies, X-ray diffraction and the Van der Pauw method, respectively. We find that paper morphology dominates film properties and the maximum film resistivity is obtained at the films deposited on the fibrous 80 g/m2 paper (17.5 μΩcm for Au and 12.1 μΩcm for Ag). Lower values are obtained for the 200 g/m2 paper (10.4 μΩcm for Au and 4.1 μΩcm for Ag). The potential of the investigated templates for electronics and sensor applications will be discussed. References [1] “Three-dimensional microfluidic devices fabricated in layered paper and tape”. A. W. Martinez et al., PNAS, 105, 19606 (2008) [2] “Foldable Printed Circuit Boards on Paper Substrates”. A. C. Siegel et al., Adv. Funct. Mater. 20, 28 (2010) [3] "IZO deposition by RF and DC sputtering on paper and application on flexible electrochromic devices". L. Gomes et al. Displays 34, 326 (2013)
Acknowledgements: Funding from the E.C. through a FP7-ICT project (Grant No. 318144) and MINECO (ref.: MAT2014-59772-C2-1-P) is acknowledged.
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Tina Stäbler, German Aerospace Center, Institute of Structures and Design, Germany
Hannah Böhrk, German Aerospace Center, Institute of Structures and Design, Germany
Heinz Voggenreiter, German Aerospace Center, Institute of Structures and Design, Germany
Abstract: Damage to thermal protection systems (TPS) during atmospheric re-entry is a severe safety issue especially when considering re-usability of space transportation systems. There is a need for structural health monitoring systems and non-destructive inspection methods. However, damages are hard to detect. When ceramic matrix composites, in this case carbon fibre reinforced silicon carbide (C/C SiC), are used as a TPS, the electrical properties of the present semiconductor material can be used for health monitoring, since the resistivity changes with damage, strain and temperature. A sensor network is applied for locally and time resolved monitoring of the 300mm x 120mm x 3mm panel shaped samples. Since the material is used for atmospheric re-entry, it needs to be characterised for a wide range of temperatures, in this case as high as 1200°C. Therefore, experiments in an inductively heated test bench were conducted. Firstly, a reference sample was used with thermocouples for characterising the temperature distribution across the sample surface. Secondly, electrical resistance under heat load was measured, time and spatially resolved. Results will be shown and discussed in terms of resistance dependence on temperature, with the thermal coefficient of electrical resistance and electrical path orientation including an analysis on effective conducting cross section. Conversely, the thermal coefficient can also be used to determine the material temperature as a function of electrical resistance.
Acknowledgements: This work is financed by the Helmholtz Alliance as the Helmholtz Young Investigator's Group VH-NG-909 'High Temperature Management in Hypersonic Flight'.
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aouni khadoudja, Laboratory Modeling of Renewable Energy Devices and Nanoscale MoDERNa, electronic department Mentouri brother Constantine University, Algeria
Abstract: In this paper the dynamic effects of quantum well laser (QWL) has been investigated by solving the numerical simple rate equation according to injection current effect. Calculating of the photons density and the carriers’ density and the output power are the objectives of the presented study. It has been found that the output power becomes more important at high injection current and lower active region thickness.
Acknowledgements: This work was supported by Laboratory of Modelling of Renewable Energy and Nanoscale MoDERNa, Constantine University, Algeria.
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Rinat Esenaliev, University of Texas Medical Branch, Center for Biomedical Engineering, United States
Abstract: Our group proposed to use an optoacoustic technique for noninvasive biomedical imaging, monitoring, and sensing. This technique combines high optical contrast with ultrasound resolution, if short optical pulses are used to generate optoacoustic waves in tissue and wide-band piezoelectric transducers are used for time-resolved optoacoustic wave detection. We developed and built optoacoustic systems with unique, ultra-sensitive, wide-band (0.05 – 40 MHz) piezoelectric probes for monitoring and imaging and tested them in animals and human subjects. These probes provide detection of optoacoustic and ultrasound wave with high signal-to-noise ratio and high spatial resolution. The obtained results demonstrate high accuracy and specificity of measurements resulted from the high-resolution detection of these waves from tissues of interest [1-6]. We will discuss other applications of wide-band piezoelectric transducers developed by our group for noninvasive monitoring of important physiologic parameters. REFERENCES 1. Petrova I.Y., Y.Y. Petrov, R.O. Esenaliev, D.J. Deyo, I. Cicenaite and D.S. Prough. Noninvasive monitoring of cerebral blood oxygenation in ovine superior sagittal sinus with novel multi-wavelength optoacoustic system. Optics Express, v.17(9), pp. 7285-7294, 2009. 2. Esenaliev R.O. Biomedical Optoacoustics. Journal of Innovative Optical Health Sciences, 2011, v.4(1), pp. 39-44. 3. Petrov I.Y., Y. Petrov, D.S. Prough, D.J. Deyo, I. Cicenaite and R.O. Esenaliev. Optoacoustic monitoring of cerebral venous blood oxygenation through extracerebral blood. Biomedical Optics, v.3(1), pp. 125-136, 2012. 4. Petrov I.Y., Y. Petrov, D.S. Prough, I. Cicenaite, D.J. Deyo and R.O. Esenaliev. Optoacoustic monitoring of cerebral venous blood oxygenation through intact scalp in large animals. Optics Express, v.20(4), pp. 4159-4167, 2012. 5. Petrov A., Wynne K.E., Parsley M.A., Petrov I.Y., Petrov Y., Ruppert K.A., Prough D.S., DeWitt D.S., and R.O. Esenaliev. Optoacoustic monitoring of cerebral venous blood oxygenation through extracerebral blood. Photoacoustics, 2014, v.2(4), pp.1-6. 6. Petrov I. Y., Y. Petrov, D. S. Prough, C. J. Richardson, R. A. Fonseca, C. S. Robertson, C. V. Asokan, A. Agbor, R. O. Esenaliev, “Transmission (forward) mode, transcranial, noninvasive optoacoustic measurements for brain monitoring, imaging, and sensing,” Proc. of SPIE, vol. 9708, pp. 97084P1-8, 2016.
Acknowledgements: The authors acknowledge support of these studies by the NIH (Grants # U54EB007954, R01EB00763, R01NS044345, R41HL103095, R43HD075551, and R41HD076568), Noninvasix, Inc., John Sealy Memorial Endowment Fund for Biomedical Research, Moody Center for Traumatic Brain Injury Research, UTMB Business Acceleration Program, and Texas Emerging Technology Fund.
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Evie Papadopoulou, Istituto Italiano di Tecnologia, Smart Materials, Italy
Davide Morselli, Istituto Italiano di Tecnologia, Smart Materials, Italy
Mirko Pratto, Istituto Italiano di Tecnologia, Nanochemistry, Italy
Alessandro Barcellona, Istituto Italiano di Tecnologia, Nanophysics, Italy
Athanassia Athanassiou, Istituto Italiano di Tecnologia, Smart Materials, Italy
Ilker Bayer, Istituto Italiano di Tecnologia, Smart Materials, Italy
Abstract: Ammonia is a common reductive toxic gas derived from waste, fertilizers and natural processes, and it is found in spoilt food, water, soil and air. Because of its importance in environmental and health issues extensive efforts were recently made in order to produce reliable ammonia sensors . Herein, we present an ammonia sensor that is based on pure Pyromellitic dianhydride–4,4-oxydianiline (PMDA-ODA, commercial name Kapton). The material is solution cast on microscope glass slides or cotton textiles and cured at 200 °C. The thin coatings have been studied for detection and quantification of ammonia (NH3) vapors originating from ammonia solutions of different molarities, from 3.5 mM to 1.5 M. The sensing of ammonia vapors is studied by measuring the changes in the electric current intensity, when the ammonia solution is injected in the sensing chamber. The sensor exhibits fast response to ammonia vapors, for aqueous ammonia solutions with molarity as low as 3.5 mM. Since ammonia is a reducing gas, the sensor sensitivity is calculated by calculating the Rair/Rvapor, where Rair is the resistance of the sensing element in air, and Rvapor is its resistance when it is in contact with the ammonia vapors . The chemical changes that occur at the polymer surface during exposure to ammonia vapors have been investigated by FTIR and XPS, revealing that the sensing is the result of the assembly of the ammonia molecules on the polymer surface. Control experiments have been performed at the commercial polymer, and show negligible sensitivity of the commercial product to ammonia vapors from different ammonia solution molarities. The sensor responce of the thin film and textie are compared. A device is also presented, to demonstrate the real time detection of ammonia vapors.
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Nikita Kulesh, Ural Federal University, Magnetism and magnetic nanomaterials, Russian Federation
Konstantin Balymov, Ural Federal University, Magnetism and magnetic nanomaterials, Russian Federation
Egor Kudyukov, Ural Federal University, Magnetism and magnetic nanomaterials, Russian Federation
Vladimir Vas'kovskiy, Ural Federal University, Magnetism and magnetic nanomaterials, Russian Federation
Vladimir Maltsev, Ural Federal University, Magnetism and magnetic nanomaterials, Russian Federation
Abstract: Magnetoelastic effect in conjunction with anisotropic magnetoresistance (AMR) was proposed for sensors of linear strain and pressure back in 1980s. Latter, giant and tunnel magnetoresistances were employed in order to increase sensitivity. However, for applications, good linearity and temperature stability of the respond are often more important. In this work we considered optimization of films containing layers of 3d-metals alloys with unidirectional anisotropy (UA) and AMR aiming stable linear respond in a moderate temperature range. Samples FeMn/M(80) and Tb-Co/M(80) (M = Fe-Ni or Fe-Ni-Co), where thickness in nm is specified, were deposited onto the glass substrates (cut into 2×15 mm stripes). Mechanical stress was applied by bending the substrate. After obtaining the preliminary results on M(80) with and without UA, hysteresis properties were measured in cyclic deformation regime and compared for various samples. Further optimization included annealing of M(80) layer to increase AMR and introduction of the nonmagnetic spacer to control the UA. Finally, temperature behavior of AMR sensitivity to the external magnetic field was analyzed, which allowed us to find configuration with most linear AMR respond over the considered temperature range (up to 150 C). In conclusion, we demonstrated close-to-linear respond and constant sensitivity over the wide temperature range by adjusting the UA and exploiting the decrease of AMR and UA in functional layer with temperature increasing.
Acknowledgements: This work was supported by The Ministry of Education and Science of the Russian Federation, project RFMEFI57815X0125.
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Saeideh Rahbarpour, Shahed university, Electrical engineering, Iran (Islamic Republic of)
Abstract: Gold nanoparticles have been increasingly used as catalytic material since 1997, when their chemical activity was discovered. Here, chemical activity of gold contacts in Au-TiO2-Ti structures is reported and verified experimentally. Diode type Au-TiO2-Ti structures was fabricated by Au deposition on thermally oxidized titanium film. The samples demonstrated I-V characteristics of a typical Schottky diode at operated temperatures up to 400 ̊C, the highest examined temperature. The Schottky barrier height (SBH) of different fabricated Au-TiO2 junctions was measured. It was shown that the measured SBHs depended strongly on the temperature and particle size of utilized gold contacts and could vary in the range of 1 to 1.8 eV. The hydrogen sensing properties of the samples were also investigated. The samples demonstrated high sensitivity to hydrogen; 1 Vol% of hydrogen in air could increase the reverse current of the diodes ~1000 times. The results are described based on the reactions taking place at the Au/TiO2 interface.
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Mohamed El-Asfoury, Egypt-Japan University of Science and Technology, Department of Materials Science and Engineering, Egypt
Koichi Nakamura, Kyoto University, Center for the Promotion of Interdisciplinary Education and Research, Japan
Ahmed Abd El-Moneim, Egypt-Japan University of Science and Technology, Department of Materials Science and Engineering, Egypt
Abstract: Development of highly efficient thermoelectric materials is indispensable for future applications in power generation and refrigeration. Bismuth-antimony (Bi-Sb) alloy is one of the most promising thermoelectric materials for the low-temperature range less than 200K, and recently we have succeeded in fabricating a novel composite material based on Bi85Sb15 with good thermoelectric performance. In this study, thermoelectric properties of Bi-Sb alloy system were simulated on the basis of first-principles calculation, to discuss the potential for thermoelectric devices. Atomistic model structures were devised by replacing some atoms in bulk Bi and Bi nanostructure models with Sb atoms under the periodic boundary condition. The displacement of Sb atom in Bi was investigated with respect to temperature by the quasi-harmonic approximation through phonon calculation, and dependence of Seebeck coefficient on composition, scale, and temperature has been demonstrated by using our original methodology in terms of the electronic state of Bi-Sb alloy system. Compared with the bulk Bi-Sb models, a significant increase of the absolute value of Seebeck coefficient can be observed in Bi-Sb nanostructure models owing to change of electronic state or quantum confinement by dimensional reduction. In addition, the influence on phonon change by Sb doping to thermoelectric properties shall be discussed at the conference.
Acknowledgements: This work was supported by JSPS KAKENHI Grant and partly conducted in the E-JUST project sponsored by the Japan International Cooperation Agency (JICA).
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Seung Koo Park, Electronics and Telecommunications Research Institute, Transparent Transducer and UX Creative Research Section, Korea, Republic Of
Abstract: Crosslinked poly(dimethylsiloxane) (PDMS) films have been well known for elastomer materials. The crosslinked PDMS films are obtained by a reaction between vinyl groups and hydridosilane groups in the PDMS (platinum-catalyzed hydrosilylation). We synthesized high molecular weight PDMS containing the vinyl groups for obtaining the crosslinked PDMS films with high mechanical properties. Diethoxydimethylsilane was reacted with diethoxymethylvinylsilane to prepare the copolymerized PDMS, poly(dimethylsiloxane-co-methylvinylsiloxane) (1). As a crosslinker, we also prepared poly(dimethylsiloxane-co-methylsiloxane) (2) by a copolymerization reaction between diethoxydimethylsilane and diethoxymethylsilane monomers. The number-average molecular weight and polydispersity of copolymers 1 and 2 were ca. 10.6×104 g/mol, 1.61 and 0.60×104 g/mol, 3.05, respectively. The crosslinked PDMS films fabricated from the mixture of copolymers 1 and 2 showed high transparency in a visible region (T> 93% @ ca. 200 ㎛ in film thickness). We investigate variation in electrical and mechanical properties of the PDMS films with formulation ratios between the copolymers. Finally, we examine the crosslinked PDMS films with the high molecular weight as a candidate for electrical actuators.
Acknowledgements: This work has been supported by the Pioneer Program of Korea National Research Foundation (2013M3C1A3059557).
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Del Atkinson, Durham University, Department of Physics, United Kingdom
Abstract: Touch sensitive surfaces have become increasing important for human interactions with electronics technology and this has had a major impact on the ways that users interact with technology. Touch sensitive surfaces, such as thin-film sensors, trackpads and touch-screens are widely used for controlling machinery, information and commercial transaction electronics and, of course, as the primary interface in mobile consumer electronics, such as smart phones, tablets and laptop computers. Current touch technology is dominated by touch interfaces that can sense only the presence/absence of a touch or the 2D planar location of a finger touch, but not the force or pressure applied by the touch. Force sensing gives an additional degree of freedom for input control. Here the underlying principle of several force sensitive touch sensing technologies are described and compared, with a focus on functional ink-based materials for producing pressure sensors and force sensing surfaces [1]. [1] Tactile Sensing in human-computer interfaces: The inclusion of pressure sensitivity as third dimension of user input. SJ Dempsey, M. Szablewski and D. Atkinson Sensors and Actuators A 232, 229-250 (2015)
Acknowledgements: Dr Sarah J. Dempsey and Marek Szablewski
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Arif Kösemen, Muş Alparslan University, Department of Physics, Turkey
Yasin Şahin, Institute of Forensic Medicine, Department of Physics, Turkey
Mustafa Erkovan, Sakarya University, Department of Nanoscience and Nanoengineering, Turkey
Necmettin Kılınç, Nigde University, Department of Mechatronics Engineering, Turkey
Sadullah Öztürk, Fatih Sultan Mehmet Vakif University, Department of Biomedical Engineering, Turkey
Abstract: In this study, we focused on investigation of electrical and gas sensing properties of ZnO nanorods with the diameters 70nm. ZnO nanorods were synthesized in nitrate solution at 90°C in autoclavable chamber. Fabricated samples were aged at illuminated and dark ambient for different periods for understanding electrical conduction and gas sensing mechanism. With direct wide band gap (3.37eV) and large exciton binding energy Zinc oxide (ZnO) is an oxide semiconductor and it is very suitable candidate for using as a photodetectors or light emtting devices, thin film transistors and gas sensors. with a large exciton binding energy of 60 meV. On the other hand, nanostructured ZnO with high aspect ratio have been investigated for increasing device performance [1-3]. Hydrothermal deposition technique was used for producing ZnO nanorods. ZnO nanorods were fabricated on ITO glass substrate for investigating electrical and gas sensing mechanism along the nanorods. Chemical reactions, producing parameters were explained in our previous works [4]. After fabrication of ZnO nanorods, Ag thin film was coated ZnO nanorods and the thickness was approximately 100 nm. Electrical measurements were performed in dark and illuminated test chamber. ZnO is very sensitive to any changes in gas concentration, the test chamber was purged by ultra pure dry air. Normally, ZnO is a native n-type semiconductors, current was expected to increase with temperatures, but the current decreased to 400 K and then increased. The decreasing of current is linked to the turning back electrons from trapped electron stimulated by light at defect levels and ZnO has a wide band gap, the currents of electrons located at valance band is so low and after 400K, valance electrons passed to conduction band very rapidly and so the current increased. On the other hand, ZnO nanorods were tested to 100 ppb, 100 ppb, 250ppb, 500 ppb and 1 ppm NO2 in dark and illuminated dry air ambient. Resistance versus time curves was given in figure3. It is clearly seen in figure 3 that although, sensitivity of ZnO nanorords is low in dark ambient response and recovery times are fast to other ambient.
Acknowledgements: This study was supported by The Scientific and Technological Research Council of Turkey. Project title: “Development of Automotive Gas Sensors Based on Nano-Metal-Oxide Semiconductor with increased Selectivity, Sensitivity and Stability” and project number “111M261.”
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Oluleke Bamodu, The University of Nottingham Ningbo China, Centre of Sustainable Energy Technologies (CSET), Department of Architecture and Built Environment, China
Sannia Mareta, The University of Nottingham Ningbo China, Department of Mechanical, Materials and Manufacturing Engineering, China
Yiyi Wu, The University of Nottingham Ningbo China, Department of Chemical and Environmental Engineering, China
Zhuge Yan, The University of Nottingham Ningbo China, Department of Electrical and Electronic Engineering, China
Abstract: For industrial and working environment, there is a growing challenge of being able to locate the components more efficiently and avoid work-related accidents, particularly in order to achieve safety and security values. This work describes the design and development of a novel multi-tasking “smart glove” which integrates the functions of sensors and actuators, associated with a control algorithm. The device incorporates a systematic assessment of human behaviour based on a real-time control feedback of navigating particular objects within the proximity range. In addition, it provides direct alertness mechanism based on the necessity of ‘danger detection’ as a precaution of human accidents in the work space by utilizing a vibration buzzer system. The developed device, called “SOZY W&D Glove”, is implemented as a wearable “Work & Detect” glove for industrial applications. It is demonstrated that the developed system has satisfactorily facilitated the needs of human awareness, where the deploying of such mechanism can be further adjusted to other forms of wearable devices for various applications.
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Takanari Saito, Tokyo University of Agriculture & Technology, Department of Electrical and Electronic Engineering, Japan
Yusuke Kihara, Tokyo University of Agriculture & Technology, Department of Electrical and Electronic Engineering, Japan
Jun-ichi Shirakashi, Tokyo University of Agriculture & Technology, Department of Electrical and Electronic Engineering, Japan
Abstract: Recently, wearable health-monitoring devices have been widely applied in disease diagnosis and health assessment. Carbon-based materials have high flexibility and sensitivity, and are good potential candidates for the wearable health-monitoring devices [1, 2]. However, the fabrication of carbon nanotube-based wearable devices is, in many cases, a complicated multistep procedure which results in the waste of materials and requires expensive facilities. Therefore, new low-cost materials and simple fabrication processes for wearable health-monitoring devices are strongly required. A commercially available pyrolytic graphite sheet (PGS) [3] is an inexpensive flexible sheet, and is easy to cut into any desired shapes and sizes using knives or scissors. Previously, we have reported the use of thin graphite films as strain sensors, which were fabricated by cutting PGSs [4]. The unique properties of the thin graphite films make it suitable for the application in flexible devices. In this paper, we focused on PGS as low-cost, simple flexible materials and investigated wearable devices based on PGS for monitoring human activity. First, we investigated a data glove using PGSs for the detection of finger motion. The thin graphite films were fabricated by cutting small films from 17-µm-thick PGSs. The data glove was then made from the thin graphite films assembled on a commercially available rubber glove. The motion of each finger could be detected individually and precisely using the data glove. Then, the application of wearable devices based on thin graphite films in monitoring human physiological signals was also investigated. The thin graphite film used as the strain sensor was attached over the radial artery to monitor wrist pulse. The wrist pulse could be clearly detected using the strain sensor. Therefore, these results suggested that the wearable devices based on thin graphite films may broaden their application in cost-effective wearable electronics for the detection of human motion and human physiological signals. References [1] T. Yamada, Y. Hayamizu, Y. Yamamoto, Y. Yomogida, A. I. Najafabadi, D. N. Futaba, and K. Hata, "A stretchable carbon nanotube strain sensor for human-motion detection", Nat. Nanotechnol., vol 6, pp. 296-301, 2011. [2] Y. Wang, L. Wang, T. Yang, X. Li, X. Zang, M. Zhu, K. Wang, D. Wu, and H. Zhu, "Wearable and Highly Sensitive Graphene Strain Sensors for Human Motion Monitoring", Adv. Funct. Mater., vol 24, pp. 4666-4670, 2014. [3] Pyrolytic Graphite Sheet Product Datasheet, Panasonic Industrial Devices, Japan. [4] T. Saito, H. Shimoda, and J. Shirakashi, "Investigation of strain sensors based on thin graphite wires", J. Vac. Sci. Technol., vol 33, pp. 042002-1-5, 2015.
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Oscar Perez-Landeros, Autonomous University of Baja California, Institute of Engineering, Mexico
Abstract: A method for preparation of very thin Au nanomesh by template based deposition is presented. The method does not use sacrificial layer in contrast to the most commonly used techniques. The nanomesh is obtained by thermal evaporation of Au on template of vertically aligned high density TiO2 nanotubes. Important characteristics, such as inner diameter and wall thickness can be varied by adjusting the corresponding parameters of the TiO2 template. Additional control can be achieved by variation of the Au deposition conditions. The obtained nanostructures were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), UV-Vis technique, Spectroscopic Ellipsometry and I-V measurements. The elastic properties were evaluated using stretchable polymer used in semiconductor industry. SEM images prove formation of well-defined Au nanomesh, which follows exactly the nanotube template. The EDS analysis reveals that the elemental composition of the mesh is gold; no contaminants from the TiO2 were detected. The studied Au nanostructures exhibit high stretchability and transparency. The electrical current through the mesh depends on the stretching conditions. The studied nanomesh structures are interesting for application in optical and gas sensors, nano-opto-electro-mechanical systems, organic photovoltaic devises and foldable electronics.
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Vladan Mlinar, Research Institute for Advanced Materials Design, Materials Science, United States
Abstract: The remarkable, layer-dependent properties of molybdenum disulphide (MoS$_2$), such as an appropriately small and sizable bandgap or interplay between spin and the valley degrees of freedom, make it an attractive candidate for photodetectors, electrominescent devices, valleytronic devices, etc. Using nanostructuring to manipulate the size in lateral direction or number of layers of MoS$_2$, we are opening a new playground for exploring and tuning properties of such systems. Here, we theoretically study the electronic properties of nanostructured MoS$_2$ systems consisting of monolayer and multilayer MoS$_2$ regions. In our analysis we consider hybrid systems in which monolayer region is surrounded by multilayer region and vice versa. We show how energy spectra and localization of carriers are influenced by the size and shape of the regions in lateral direction, number of MoS$_2$ layers in the multilayer region, and the edge structure. Finally, we demonstrate how to control localization of carriers in these hybrid systems, which could make them appealing candidates for optoelectronic devices. Our findings are extracted from a tight-binding model that includes non-orthogonal sp$^3$d$^5$ orbitals, nearest-neighbor hopping matrix elements, and spin-orbit coupling.
40
Mehdi Othman, Aix-Marseille University, IM2NP, France
Abstract: We report on the synthesis of copper tungsten oxide thin films by means of modified reactive sputtering process using tungsten target decorated with small pieces of copper. By adjusting the Cu to W surface coverage ratio, we obtained different compositions as confirmed by XRD analysis. We demonstrate that it’s possible to synthetize CuWO4 thin film by mean of RF sputtering using W target by adjusting the Cu to W surface coverage. Two thin-films was realized based on different W target surface covering by Cu. Sample A was deposited by covering 6.25 % of the W target surface by Cu targets while in the second case, Sample B was realized with 12.5 % of the W surface covered by cu targets. The crystallinity of the synthesized thin films was characterized by x-ray diffraction. For sample A, the formation of single phase CuWO4 in the triclinic crystal structure, space group P-1 has been confirmed by comparing the XRD data with database standards (reference database pattern # 01-070-1732). It should be noticed that CuWO4 is wide gap n-type semiconductor (2.3 eV). Nonetheless, sample B show an XRD pattern which is attributed probably to the coexistence of two phases CuO and WO3 according to reference database pattern. The sensing performance was evaluated by measuring the resistance of thin-films as a function of time under CO rich atmosphere. The temperature was maintained constant at 230°C during the experiment and the sensitive layer was biased by a fixed voltage of 0.5 V. The response of the samples is defined as the ratio of the resistance under dry air to the resistance under carbon monoxide. The CO response of the two samples to 90 ppm CO demonstrates that sample A which represents CuWO4 exhibits a good sensitivity in respect to sample B. furthermore, sample B shows a rapid saturation to carbon monoxide and long recovery time in respect to sample A.
41
Tahereh Akbari, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran (Islamic Republic of)
Pantea Dara, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran (Islamic Republic of)
Abstract: Long life, compact and low cost general gas sensors are in demand for volatile organic compound (VOC) monitoring in the domestic and industrial premises. Here, we report the fabrication and assessment of an Au/TiO₂ Schottky diode whose I-V characteristics are VOC-sensitive and can perform as a general VOC detector at elevated operating temperatures. Rutile layer is grown by the controlled oxidation of titanium foil at 700 °C, and gold top electrode is deposited on the grown oxide by the thermal evaporation of the metal in vacuum. The I-V characteristics of the device are plotted and the junction energy barrier is determined at different temperatures. It is shown that the junction energy barrier varies with the change in the composition of the surrounding atmosphere. Both forward and reverse biased diodes are examined for VOC detection. The reverse biased diode operating at 250 °C demonstrates the highest sensitivity. At a constant reverse bias, the current of the diode increases by as much as 25% in response to the presence of 20 ppm ethanol in the test chamber. The shortcoming of the device is related to its long response and recovery times, which are connected to the desorption/adsorption of the oxygen species from/to the gold surface.
42
ALCIVIADIS-CONSTANTINOS CEFALAS, NATIONAL HELLENIC RESEARCH FOUNDATION, THEORETICAL & PHYSICAL CHEMISTRY INSTITUTE, Greece
Abstract: A.C. Cefalas *, V. Gavriil and E. Sarantopouloua National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635, Greece. V. V. Semashkob and V. Pavlovb Kazan Federal University, Institute of Physics, 18 Kremljovskaja str., Kazan 420008, Russia. Abstract Electron energy gradients along opposite conductive paths in amorphous 2-D nanostructures, for opposite bias voltage polarities, have opposite algebraic signs and this translational behavior intrinsically imposes a current stability anisotropy along opposite conductive paths. For either long conductive paths (L >1 μm) or along symmetric nanodomains, current is stable for both positive and negative currents i. On the contrary, for short conductive paths along non-symmetric nanodomains, the set of independent variables (L, i), where L is the conductive path is spanned by two current stability loci. One locus specifies a unidirectional stable state for negative currents only, while the other locus describes a unidirectional stable state for positive currents. Results for amorphous 2-D tantalum oxide semiconductive layers point to the importance of local morphological features in thin amorphous layers for stable nanoelectronic operation.
43
Bourfaa Fouzia, University constantine, physics, Algeria
Abstract: Silver nanoparticles were synthesized injecting sodium citrate solution into the solution of silver nitrate at high temperature. The silver colloid was prepared by using a chemical method then ZnO thin films with the incorporation of various content of Silver Nanoparticles (Ag NPs) were deposited on microscope glass substrate by sol-gel method at room temperature. The films obtained were annealed at 500°C for 2 Hours. The crystalline structure of films was characterized by means of X-Rays diffraction. The surface morphology was investigated by Scanning Electron Microscopy (SEM). The obtained colloids of Ag nanoparticles and optical properties of ZnO thin films are studied by UV–Visible spectroscopy within the range of 200-800 nm. The diameter of Ag NPS was measured by Zeta Sizer.
44
Boutelala Abderhamane, University constantine, physics, Algeria
Abstract: Titanium dioxide (TiO2) thin films doped Cobalt were prepared by dip-coating sol-gel method with varying number of dipping (layers) onto glass substrate . In this present work, we study the effects of number of layers on the properties of Co doped TiO2 thin films. The structural properties of obtained films were analyzed by means of X-Rays diffraction. The surface morphology of films was characterized by Scanning Electron Microscopy (SEM). The optical properties were investigated by UV-Visible spectroscopy. The electrical conductivity measurement was achieved in dark at room temperature in a coplanar structure with two evaporated gold stripes contacts onto film surface. The number of dipping has an effect on the optical perperies of the obtained films so the transmittance deacrease with the increasing of layers
45
VASSILIOS GAVRIIL, NATIONAL HELLENIC RESEARCH FOUNDATION, THEORETICAL & PHYSICAL CHEMISTRY INSTITUTE, Greece
ALCIVIADIS-CONSTANTINOS CEFALAS, NATIONAL HELLENIC RESEARCH FOUNDATION, THEORETICAL & PHYSICAL CHEMISTRY INSTITUTE, Greece
EVANGELIA SARANTOPOULOU, NATIONAL HELLENIC RESEARCH FOUNDATION, THEORETICAL & PHYSICAL CHEMISTRY INSTITUTE, Greece
Abstract: Point spread function (PSF) is the response of an optical system to a point light source. Optical Transfer Function (OTF) is the Fourier Transform of the PSF. It is a measure of the quality and the resolution of optical and image analysis systems,such as an iris/lens optical system and a CMOS sensor. Overall OTF is a product of the OTFs of optical system (lens) and image sensor (CMOS sensor). In this work, a theoretical calculation of optical system’s PSF and OTF which accounts for both diffraction and aberration parameters (spherical, comma, astigmatism, etc) leads to the estimation of sensor`s OTF derived from the final image registered in the sensor and results are compared with experimental data.
46
Milad Ghalamboran, K. N. Toosi University of Technology, Faculty of electrical engineering, Iran (Islamic Republic of)
Mojtaba Jahangiri, K. N. Toosi University of Technology, Electrical Engineeing Department, Iran (Islamic Republic of)
Ehsan Yousefiazari, K. N. Toosi University of Technology, Electrical Engineeing Department, Iran (Islamic Republic of)
Abstract: Intensive research has been conducted on ZnO thin and thick films in recent years. Such layers, used in different electronic devices, are deposited utilizing various methods, but electrophoretic deposition (EPD) has been chosen because of the advantages like low energy consumption, economical superiority, ecofriendlyness, controllability, and high deposition rate. Here we report electrophoretically depositing ZnO layers onto highly oriented pyrolytic graphite. Well-dispersed and stable ZnO suspensions are required for the deposition of continuous and even layer of ZnO on the substrate. ZnO powder is dispersed in acetone. The electric field applied is 250 V/cm, the counter electrode is aluminum foil, and the deposition time is 10 min. the morphology of the deposits are studied by SEM micrographs recorded at the different stages of the deposition process.
47
Afroditi Petropoulou, National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Photonics for Nanoapplications Laboratory and University of Peloponnese, Department of Informatics and Telecommunications, , Greece
Thomas J. Gibson, Queen's University Belfast, Belfast BT9 5AG, UK, School of Chemistry and Chemical Engineering, United Kingdom
Efrosyni Themistou, Queen's University Belfast, Belfast BT9 5AG, UK, School of Chemistry and Chemical Engineering, United Kingdom
Stergios Pispas, Theoretical and Physical Chemistry Institute, Photonics for Nanoapplications Laboratory, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens, 116 35, Greece, , Greece
Christos Riziotis, National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Greece
Abstract: In this work, a low cost and low complexity protein sensor based on silica optical fibers functionalized with novel amphiphilic block-copolymer materials has been proposed and experimentally investigated. The combination of both hydrophobic and hydrophilic blocks in the vinyl-sulfone functionalized PMMA117-b-P(DMAEMA17-VSTEMA2) block polymer used here facilitates the formation of stable overlayers on the silica surface. The PDMAEMA block is extensively protonated at low pH. The presence of the cationic block and the vinyl-sulfone double bonds, lead to electrostatic binding of negatively charged proteins and chemical binding by thiol-ene reaction with cysteine in proteins, respectively. This enable efficient sensing due to the induced refractive index change to the overlayer. The PMMA-b-PDMAEMA block copolymer was used as a control for the detection of bovine serum albumin (BSA) protein which is negatively charged at neutral pH, exhibiting linear response to different BSA concentrations.
48
Ebrahim Nadimi, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran, Islamic Republic Of
Saeed Masoumi, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran (Islamic Republic of)
Amirreza Noori, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran, Islamic Republic Of
Abstract: Zinc oxide (ZnO) is currently under intensive investigation, as a result of its various applications in microelectronic, nanoelectronics and optoelectronics. However, a stable and reproducible p-type doping of ZnO is still a main challenging issue. Group IB elements such as Au, Cu and Ag, generally supposed to substitute Zn lattice sites, are one of the major candidates for p-type doping. In spite of many efforts, the current understanding of Ag defects in ZnO is still ambiguous. In this work, we report the results of our first-principles calculations based on density functional theory for Ag defect, particularly the interstitial and substitutional defects in ZnO crystal. The interaction between Ag atoms and oxygen vacancies in the host ZnO crystal is also reported. Defects formation energies are calculated in different charged states as a function of Fermi energy in order to clarify the p-type behavior of Ag-doped ZnO. We also investigate the diffusion behavior and migration paths of Ag in ZnO crystal in the framework of density functional theory applying climbing image (CI) nudged elastic band method (NEB).
49
Amirreza Noori, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran, Islamic Republic Of
Amirreza Noori, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran, Islamic Republic Of
Saeed Masoumi, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran (Islamic Republic of)
Najmeh Hashemi, K.N.Toosi University of Technology, Faculty of Electrical Engineering, Iran, Islamic Republic Of
Babak Sadiye, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran, Islamic Republic Of
Abstract: Thermoelectric devices are reliable tools for converting waste heat into electricity as they last long, produce no noise or vibration, have no moving elements, and their light weight makes them suitable for the outer space usage. Materials with high thermoelectric figure of merit (zT) have the most important role in the fabrication of efficient thermoelectric device. Zinc oxide has recently received attention as a material suitable for sensor, optoelectronic and thermoelectric device applications because of its wide direct bandgap, chemical stability, high-energy radiation endurance, good transparency and acceptable zT. Understanding the electric and thermoelectric properties of the undoped ZnO thin films can help design better ZnO-based devices. Here, we report the results of our experimental work on the thermoelectric properties of the undoped polycrystalline ZnO thin films. These films are deposited on alumina substrates by thermal evaporation of zinc in vacuum followed by a controlled oxidation process in air carried out at the 350-500 ℃ temperature range. The experimental setup including heaters, thermometry system and Seebeck voltage measurement equipment for high resistance samples is described. Seebeck voltage and electrical resistivity of the samples are measured at different conditions. The observed temperature dependence of the Seebeck coefficient is discussed.
50
Konstantinos Bidinakis, NCSR Demokritos, Institute of Nanoscience and Nanotechnology, Greece
Abstract: K. Bidinakis and Th. Speliotis, Institute of Nanoscience and Nanotechnology, NCSR Demokritos, Greece Abstract: Bismuth-based binary chalcogenide compounds such as Bi2Te3 and Bi2Se3 are well known materials for their excellent thermoelectric properties due to their near-gap electronic structure. In the last few years these materials have received attention for exhibiting new physics of 3D topological insulators (TI). Possible applications of TI based devices range from quantum computing, spin based logic and memory and electrodynamics. The 3D TI presents spin-momentum-locked surface states by time reversal symmetry (TRS). Introducing magnetic doping in a TI brakes the TRS and is predicted to open the gap at Dirac point resulting in exotic quantum phenomena. This interaction between magnetism and topologically protected states is a potential attention for applications in modern spintronics. In this work granular Mn-Bi2Te3 thin films grown by DC magnetron sputtering on Si(111) substrates and ex situ annealing. We present results of the crystal structure of sputtered and annealed films characterized with x-ray diffraction and high-resolution scanning electron microscopy (HRSEM). The surface analysis was studied with atomic force microscopy (AFM). Magnetotransport measurements were performed using standard four probe technique with Hall and MR configuration with perpendicular magnetic fields up to 9T and temperature from 300 to 5K.
51
Won-Kil Choi, Korea Institute of Energy Research, Climate Change Research Division, Korea, Republic of
Pravin Ingole, Korea Institute of Energy Research, , India
Xinghai An, Korea Institute of Energy Research, Low Carbon Process, Korea, Republic of
Muhammad Baig, Korea Institute of Energy Re, Climate Change Research Division, Korea, Republic of
Hyung-Keun Lee, Korea Institute of Energy Research, Climate Change Research Division , Korea, Republic of
Abstract: Since many industrial streams contain high concentrations of water vapor that can vary appreciably because of temperature instability. Polymer membrane process has long been used for water vapor removal from flue gas due to its reliability and high energy efficiency.[1-3] However, the application of thin film composite hollow fiber membranes for water vapor separation has rarely been reported before.[4] Therefore, in this work we have developed new thin film composite (TFC) membranes to improve the water vapor/gas separation. To remove the water vapor from fuel gas hollow fiber membrane have been fabricated and after that TFC membrane have been coated on the surface of hollow fiber substrate. For making TFC membrane first PDA has been coated inside of HF membrane and after that aqueous phase monomer piperazine (PIP) and trimesoyl chloride (TMC) used to form a TFC membrane. Water vapor permeance and selectivity drastically improved due to the increased water vapor permeation paths provided by the composite materials. The results revealed that the modified TFC membranes showed the best permeance 1590 GPU through membrane 1 and selectivity 142 through membrane 3. Polyethersulfone; interfacial polymerization; thin film composite membrane; water vapor separation
52
TAKESHI YANAI, Nagasaki University, Graduate school of Engineering, Japan
Masaki Nakano, Nagasaki University, Graduate school of Engineering, Japan
Hirotoshi Fukunaga, Nagasaki University, Graduate school of Engineering, Japan
Abstract: It is well-known that a reduction in thicknesses of soft magnetic materials for magnetic sensors and transformers is one of effective methods to reduce an eddy current loss. In the present study, a fabrication method of a soft magnetic thin ribbon was proposed. We electroplated Fe-Ni-based thin films on a Cu sheet (L350 × W5 × T0.3 mm), and then the films were peeled off physically from the Cu sheet. Consequently, we obtained the ribbon-shaped Fe-Ni thin films. The 9.2 µm-thick Fe-Ni thin ribbons were formed into toroidal core (D = 48 mm), and ac magnetic properties of the toroidal core were evaluated at Bm = 0.9 T in the frequency range from 50 Hz to 200 kHz. In order to compare high frequency properties, we also evaluated ac magnetic properties of a toroidal core prepared from a 25 µm-thick amorphous ribbon. The Fe-Ni core showed lower iron loss compared with that of the amorphous one in high frequency region (> 10 kHz). As an eddy current loss in a typical metallic soft magnetic material becomes dominantly in the high frequency region, we conclude that the prepared Fe-Ni thin ribbon is an effective soft magnetic material for high frequency driving sensors and transformers.
53
Xinghai An, Korea Institute of Energy Research, Low Carbon Process, Korea, Republic of
Pravin Ingole, Korea Institute of Energy Research, , India
Won-Kil Choi, Korea Institute of Energy Research, Climate Change Research Division, Korea, Republic of
Hyung-Keun Lee, Korea Institute of Energy Research, Climate Change Research Division , Korea, Republic of
Abstract: Recent decades have witnessed increasing fresh water shortage, and hydrophilic polyamide based thin film composite (TFC) membranes prepared by interfacial polymerisation (IP) have many promising applications in water or water vapour treatment. Nowadays, nanoparticles (NPs) incorporated thin film nanocomposite (TFN) membranes are brought to attention as they potentially enhance membrane performance.1-2 However, nanoparticles tend to agglomerate and create defects, which are considered as the main difficulty for limiting their usage. For the sake of solving this issue, we report the functionalisation of titanium dioxide (TiO2) by carboxylation and hydroxylation to improve dispersion and avoid agglomeration.3 The carboxylated titanium dioxide (c-TiO2) and hydroxylated titanium dioxide (h-TiO2) were used to prepare TFN membranes (0.05 wt% loading) by interfacial polymerisation between 3,5-diaminobenzoic acid (DABA) and trimesoyl chloride (TMC) on porous polysulfone (PSf) hollow fibre membrane support. As-prepared TFN membranes were comprehensively characterised using modern techniques and their performance were evaluated by lab scale water vapour separation system in terms of permeance and selectivity. A comparative studies were carried out to investigate the effects of titanium dioxide and functionalised titanium dioxide on membrane performance. As a result, the carboxylated titanium dioxide exhibits the highest hydrophilicity (46° in contact angle) and significantly improves membrane performance (1131 GPU in permeance, 548 in selectivity), compared with TFC membrane without nanoparticles (78° in contact angle, 780 GPU in permeance, 115 in selectivity).
54
Mahsa Rohani, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran (Islamic Republic of)
Navid Alaei-sheini, K. N. Tossi university of technology , Electrical Engineering Department, Iran (Islamic Republic of)
Niloofar Dehghani, K. N. Toosi University of Technology, Faculty of Electrical Engineering, Iran (Islamic Republic of)
Abstract: Aluminum oxide, having impressive chemical and thermal stability, is considered to be a promising material for utilization in the structure of chemical sensors. Due to high levels of resistivity, alumina is mostly employed as the sensors substrate and its ability for functioning as the sensing element has yet to be studied. Here, sensitivity of Al₂O₃ thick films to different partial pressures of oxygen is investigated at 330 ºC. Lateral Ag electrodes paste printed on the 0.5 mm thick alumina beads provide connections to the external circuitry. An electroforming step at temperatures of up to 400 ºC with initial electric fields of ~0.1 MV/m is performed to decrease the device’s resistance. SEM micrographs of the electroformed device show formation of Ag microfilaments on the surface of the polycrystalline Al₂O₃ bead. Decreasing the atmospheric pressure in the test chamber using a rotary vacuum pump, resulted in an increase in the device’s resistance. Reducing the oxygen partial pressure by a continuous flow of argon in the test chamber leads to the same results, as well. The observations are attributed to the role of atmospheric oxygen in the concentration and motion of the charged species on the surface of the device operating at elevated temperatures.
55
YingPin Wu, National Taiwan University, Graduate Institute of Electronics Engineering and Department of Electrical Engineering, Taiwan, Province Of China
Xiao-Yun Li, Academia Sinica, Institute of Physics, Taiwan, Province Of China
Pei-Hua Chen, Academia Sinica, Institute of Physics, Taiwan, Province Of China
Ying-Jay Yang, National Taiwan University, Graduate Institute of Electronics Engineering and Department of Electrical Engineering, Taiwan, Province Of China
Abstract: We report a highly sensitive gas sensor using silicon microwire field-effect-transistor (FET). The measured source-drain current (IDS) of FET reveals the information about the polarity and magnitude of net dipole produced by target-probe interaction. The detection of organic, volatile organic compound (VOC), acid and alkali molecules has been demonstrated. It shows that this sensor is more sensitive to acetic acid and the ammonia has the opposite response compared with other detected gases. The limit of detection (LOD) of acetic acid we achieved was about 34ppb. In addition, relation between the gas concentration and the rising rate of IDS can be formulated, making it possible to quantitatively determine the gas concentration by analyzing the current profile.
56
YingPin Wu, National Taiwan University, Graduate Institute of Electronics Engineering and Department of Electrical Engineering, Taiwan, Province Of China
Ding Huang, Academia Sinica, Institute of Physics, Taiwan, Province Of China
Ying-Jay Yang, National Taiwan University, Graduate Institute of Electronics Engineering and Department of Electrical Engineering, Taiwan, Province Of China
Abstract: In conventional FET-based sensor, the probe molecule binds the target molecule and then produces a net dipole. Here we demonstrated a new sensing method that target molecule is employed to cut probe molecule, and the change of molecular dipole due to a shorter molecular structure can be detected using silicon nanowire field-effect-transistor (SiNW-FET) underneath. We took xylan as the probe and xylanase (TF-R8) as the target molecule in this experiment, fragment of xylan would move away after enzyme hydrolysis, and result in a change in measured source-drain current (IDS). We further show that this sensor has good selectivity, and the limit of detection (LOD) of enzyme concentration we achieved was 10ng/ml.
57
Jan Ivanco, Institute of Physics, , Slovakia (Slovak Republic)
Abstract: Solid-state sensors of gases and vapours may dispose of a manufacture potential for simple and affordable detectors intended for specific applications. For example sensors of trace concentrations of acetone vapours could be employed as a personal monitoring device of increased acetone level in the exhaled breath of patients with diabetes type II. Sensing elements, such as e.g. films, of solid-state sensors often require higher operating temperatures by virtue of the increased and faster response, and/or technology and application issues. Yet, the chemical stability of the active elements may be a weak point. For example, the γ-α transformation of Fe2O3 nanoparticles (NPs) at elevated temperatures impairs the sensitivity and selectivity. The stability of Fe2O3 nanoparticle-based films upon isochronal annealing in air was investigated by various structural and chemical methods. We found that the γ- α transformation temperature of Fe2O3 increases for the nanostructured Fe2O3 films. The higher stability of the γ phase was explained by means of increasing the surface free energy of nanoparticles (with the size of 6.4 nm) in comparison to a continuous film. Further, chemiresistors based on the Fe2O3 NPs layered by the Langmuir-Schaefer method were prepared and explored in terms of their sensitivity to acetone vapours down to 1 ppm concentration in air, which corresponds to the approximate level associated with a healthy person, with an emphasis on the swift response.
Acknowledgements: We acknowledge the support via APVV-14-0891, VEGA 2/0010/15 and CNR-SAS 2016-2018 grants.
58
May Yang, Greyc-Ensicaen, Electronic, France
Abstract: Magneto(elasto)Electric (ME) sensors based on magnetostrictive-piezoelectric composites have been developed and widely investigated to sense magnetic signals. Previous investigations have shown that the dielectric loss noise in the piezoelectric layer constitutes the dominant intrinsic noise at low frequencies, which prevents the sensor from achieving the expected performances. Furthermore, these sensors have intrinsically no DC detection capabilities. In order to improve very low frequency signal detection, modulation techniques have been used. Moreover, classical magnetic field feedback techniques can also be applied to increase the dynamic range, the stability and improve the linearity of the system. In this paper, we propose a new method for the feedback of the system using both the magneto-capacitance modulation and an electric field feedback. Our work shows the feasibility of the method and the results match with the theoretical description and material properties. Even if the present results are not totally satisfactory, they serve as a proof of concept and yield the way to the development of very low power magnetometers based on Magneto(Elasto)Electric sensors.
59
Karima Bournane, University of Sciences and Technologie HOUARI BOUMEDIENNE, Algiers, Algeria
Abstract: The aim of this work is the comparison between Pt (Pd) / SiC-pSi and Pt (Pd) / PSC / SiC-pSi Schottky diode. The Schottky diode was characterized in air ambient and in vacuum at pressure 8.10-2 mbar. These diodes could be used for exhaust gas monitoring as gas sensors for different gas (O2, H2, CO, CO2 and hydrocarbure). The thin SiC layer are realized on p-type silicon (Si(100)) substrate by laser ablation method with KrF laser (248 nm) using 6H-SiC (purchased by Goodfellow UK) as sputtered target and a thermal deposition of a thin metal layer (Platinum (Pt) and Palladium (Pd)). The electrical measurements were made at room temperature 295 K using an oxford cryostat. We investigate the effect of nature of surface SiC and the nature of the metal on the electrical parameters such as ideality factor (n), barrier height and series resistance (Rs). Analysis of current-voltage (I–V) characteristics showed that the forward current might be described by classic thermal emission theory. The ideality factor of the I–V characteristics was found to be dependent and vary only on a modified surface such as PSC (interfacial layer) and also vary with the nature of the metal (Pt or Pd) for electrical measurements in air and in vacuum, it notes that Schottky diode without an interfacial layer (PSC), all electrical parameters does not change when the measurements were taking in vacuum or in air ambient.
60
Jon Gutiérrez, Universidad del País Vasco UPV/EHU, Facultad Ciencia y Tecnología, Departmento Electricidad y Electrónica, Spain
Ane Miren Gutiérrez Muto, Universidad del País Vasco UPV/EHU, Facultad Ciencia y Tecnología, Departmento Electricidad y Electrónica, Spain
Alazne Peña, Universidad del País Vasco UPV/EHU, Facultad Ciencia y Tecnología, Departmento Química Inorgánica, Spain
Maria San Sebastián, BCMaterials, Polymeric Materials, Spain
Catarina Lopes, BCMaterials, Polymeric Materials, Spain
Luis Lezama, Universidad del País Vasco UPV/EHU, Facultad Ciencia y Tecnología, Departmento Química Inorgánica, Spain
Izaskun Gil de Muro, Universidad del País Vasco UPV/EHU, Facultad Ciencia y Tecnología, Departmento Química Inorgánica, Spain
Abstract: We present results concerning the synthesis, magnetic, dielectric and microwave absorption properties of BaFe12O19 / P(VDF-TrFE) nanocomposites. First, Barium ferrite nanopowders were prepared by the hydrothermal synthesis method. The structural and morphological properties of the obtained powders were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM), showing as result a good quality compound of about 85 nm powder size. Afterwards, composite films with filler nanoparticles of Barium ferrite BaFe12O19 (BaFO, 5-20 %wt.) dispersed within P(VDF-TrFE) acting as piezoelectric polymeric matrix have been prepared by melting and crystallization at room temperature. We thus obtained about 85 μm thickness composite films. Magnetic properties were examined by the vibrating sample magnetometry (VSM), and a direct comparison of results obtained for the composites respect to the pure nanopowder (MS≈30 emu/g at 1.8 T, at room temperature) allowed us to correct the nanofiller content value from the initially nominal one. Dielectric properties have been measured up to 2 MHz and show the typical behaviour of Maxwell-Wagner type interfacial polarization. From 10 kHz up, permittivity of the composites remains almost unchanged. These measured values show a smooth increasing behaviour as the BaFO filler content increases in the composites that tell us about a Voigt-type mixing phases rule behaviour. Finally, microwave absorption properties were analyzed by using FMR technique operating at X-band (9.4 GHz). All recorded spectra exhibit the same essential features, showing rather large line widths (ΔHpp≈1.8 kOe) as usually happens with Barium ferrite samples. Microwave absorption increases proportionally to the ferrite content in the nanocomposite, while the magnetic field for which the maximum value is observed smoothly decreases (5%wt. - 3.01 kOe; 20%wt. - 2.95 kOe). In all cases significant absorption near zero-field has been observed.
Acknowledgements: J. Gutiérrez wants to thank the financial support from Basque Government Industry Department under Project Actimat (ELKARTEK 2015 Program). Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, ESF) is gratefully acknowledged.
61
Andoni Lasheras, University of the Basque Country, Electricity and Electronics, Spain
Jon Gutiérrez, University of the Basque Country, , Spain
Jose Manuel Barandiarán, BCMaterials, , Spain
Abstract: In last years, there is an increasing interest in magnetoelectric (ME) composites due to their potential applications in a wide range of fields such as magnetic field sensors, energy harvesting devices, transformers and microwave devices, among others. Within these ME composites, sandwich-like laminated ones display the highest ME response, particularly those fabricated with magnetostrictive amorphous alloys (or metallic glasses) and piezoelectric polymers, mainly PVDF and its copolymers. Thus, in such devices magnetostriction arisen from the metallic glass drives the elongation on the piezoelectric element, generating an induced ME voltage. This ME voltage is maximum at the magnetoelastic resonance of the laminate. As theory predicts, magnetostriction (through its H field derivative, that is the piezomagnetic coefficient), Q quality factor of the laminates resonance and piezoelectric coefficient of the PVDF, are the fundamental parameters that affect the final ME response of the device. In an attempt to achieve a simple criterion to directly compare the ME performance of such laminates when they are fabricated with different magnetostrictive constituents, we have performed magnetic and ME measurements in 3 cm long laminates, but using three different metallic glasses, all of them belonging to the same family of compounds: (Fe0.79Co0.21)75+xSi15-1.4xB10+0.4x, with x= 0, 3 and 6. All the three alloys have different magnetic and magnetostrictive properties, as well as different quality factors. The obtained ME response is analyzed in terms of all these parameters, and the convenience to define a figure of merit, F, to directly compare such ME performance, is discussed.
Acknowledgements: A. Lasheras wants to thank the Basque Government for his FPI grant. J. Gutiérrez and J. M. Barandiarán want to thank the financial support from Basque Government under projects IT711-13 and Actimat (Industry Department, ELKARTEK 2015 Program). Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, ESF) is gratefully acknowledged.
62
Shuwen Jiang, University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, China
Abstract: For aerospace and nuclear fields at high temperatures, strain gauge that can be used in various hot sections is in urgent need to provide accurate measurement of strain, fatigue and other structural parameters. In this study, PdCr thin film resistive strain gauges were fabricated on the nickel-based superalloy substrate. NiCrAlY alloy as a buffer layer was first deposited to enhance the adhesion of the following layers, YSZ/Al2O3 as a composite insulating layer was then prepared to obtain the required electric insulation, then PdCr thin film as the sensing material was sputtered, and patterned using the metal mask, finally Al2O3 thin film layer as a high temperature protective overcoat was deposited. The gauge factor, apparent strain and drift strain of PdCr thin film strain gauge at different temperatures were investigated. The results indicated that resistance value of PdCr thin film strain gauge showed an excellent linear relationship with strain at different temperatures. Gauge factor of PdCr thin film strain was measured to be 1.40 at room temperature; At 800 ℃, apparent strain sensitivity is 127 με/℃, and the resistance value of the strain gauge insignificantly decreased with time and the drift strain was about 1800 με/hr. Gauge factor at 800 ℃ was 1.41, almost the same as that of room temperature. The reproducibility and lifetime of PdCr thin film strain gauge were also evaluated. It showed that the repeatable measurement error was 6.38%, and lifetime was over 10 hours.
63
Norelhouda Medigue, USTHB, Laboratoire de Physico-chimie Théorique et de Chimie Informatique, Algeria
Safia Kellou-Tairi, University of Sciences and Technology Houari Boumediene, Theoretical and Physical Chemistry, Algeria
Abstract: Five novel Copper(II) complexes, with the non-steroidal anti-inflammatory drug tolfenamic acid (Htolf) with the oxygen-donor ligands and/or the nitrogen-donor heterocyclic ligands, taken from literature with their proposed structure (1), were modeled in this work. Non steroidal anti-inflammatory Drugs (NSAIDs) are commonly used anti-inflammatory, analgesic and antipyretic agents with known side-effects which are milder in the case of their copper(II) complexes. In order to gain a better insight into the molecular structure of the HTolf and its Cu(II) complexes, geometric optimization, spectral and electronic properties analyses were performed using DFT calculations by Schrödinger package for linux platform. 3D molecular modeling was performed in the gas phase and in DMSO as solvent using density functional theory (DFT) at the B3LYP level with Lacvp** basis set. The frequency calculations of the optimized geometry done to confirm that the optimized structures to be minimum energy and to obtain the theoretical vibrational spectrum. The stability of the optimized geometries are confirmed by frequency calculations, which give positive values for all obtained frequencies. The simulation results are used to discuss the behavior of the HTolf and the Cu(II) complexes and predict experimentally inaccessible properties and not reported in the reference paper.
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Ahmed EL HICHOU, Faculté des Sciences et Techniques, Physique Appliqué, Morocco
Abstract: Undoped and lithium doped zinc oxide thin films were successfully deposited by sol-gel method from aqueous solution onto glass substrates at optimized experimental conditions and using spin coating technique. The variations of the structural, electrical and optical properties with the doping concentration were investigated. The X-ray diffraction (XRD) analysis of the films reveals that the Li incorporation leads to the great improvement of the crystalline quality in the ZnO films. The grain size, texture coefficient and optical band gap values were evaluated for different lithium concentrations Scanning electron microscopy (SEM) images showed that nanowires are aligned nearly perpendicular to the substrate plane and are affected significantly by Li incorporation. The optical transmission of the films was higher than 85% in the visible region. It is found that the optical gap and the refractive index remain practically constant.
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Kaïssa Abdmeziem, USTHB University, Faculty of Chemistry, Algeria
Abstract: D Meziani1, Y Roumila1, R Bagtache1, M Trari2 and K Abdmeziem1 1USTHB, Faculty of Chemistry, Laboratory of Electrochemistry-Corrosion, Metallurgy and Inorganic Chemistry, BP 32 El-Alia, 16111 Algiers, Algeria. 2Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry, U.S.T.H.B., BP 32 El-Alia, 16111 Algiers, Algeria. Abstract. Our work is devoted to the design of novel materials and their applications in various fields of environmental science. Polyoxometalates constitute a kind of metal oxides that have attracted a significant interest for their properties and potential applications in the fields of electrochemistry, photochemistry, biochemistry, magnetism, energy storage…. In the present paper, we report on the synthesis and characterization of a new polyoxotungstate material that was obtained by hydrothermal route.The influence of the starting molar composition of the reaction mixture and that of other chemical parameters, such as crystallization temperature and time, pH, have been investigated. The as- synthesized material was characterized using several physicochemical techniques including: X-Ray diffraction, chemical and thermal analyses, FTIR, scanning electron microscopy and UV-Vis diffuse reflectance measurements. The optical study shows two band gaps transitions directly and indirectly allowed at 3.3 and 3.12 eV respectively. The thermal variation of the electrical conductivity that follows an exponential type law, shows a semiconductor behavior of the compound. The photoelectrochemical study was performed (in Na2SO4 medium) in order to position the energy levels of valence and conduction bands. The material exhibits n-type behaviour with a flat band potential of -0.337 V and electrons density of 6.59.1018 cm-3.
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Farida KELLOU, University of Sciences and Technologie Houari Boumediene-Algiers, Chemistry, Algeria
Abstract: The present work aims to study the electrochemical behavior of nickel oxide, formed by means of anodic polarization on the metal surface in 1N H2SO4 solution at various moderated temperatures. In attempts to learn more about the characteristic of the passive film, developed on nickel, some electrochemical techniques such as potentiodynamic and potentiostatic polarization, electrochemical impedance spectroscopy (EIS) and Mott-shottky measurements were carried out. The obtained results show that the extent of the passivation region is reduced by the temperature increase. The slope of the linear part of the Mott-Shottky plots is negative, indicating a p-type behavior of the passive layer oxide whatever the temperature. The two semiconductive parameters, the acceptor density (NA) and the flatband potential (Efb) were calculated from the Mott–Schottky graphs. The relationship between these parameters and the protective characters of the passive film against corrosion was analyzed. Co-author : Nesrine Ramli, Laboratoire d’Electrochimie-Corrosion, Métallurgie et Chimie Minérale,Faculté de Chimie/USTHB BP32 El-Alia Bab-Ezzouar Alger-Algérie
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Robert Olejnik, Tomas Bata University , Centre of Polymer Systems, University Institute, Czech Republic
Petr Slobodian, Tomas Bata University in Zlin, Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Czech Republic
Jiri Matyas, Tomas Bata University in Zlin, Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Czech Republic
Zdeno Spitalsky, Slovak Academy of Sciences, Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava 45 Slovak Republic, Slovakia
Silvia Pertegas, Christian Doppler Laboratory for High Efficient Composite processing, Department Polymer Engineering and Science, Montanuniversitaet Leoben, Austria
Ralf Schledjewski, Christian Doppler Laboratory for High Efficient Composite processing, Department Polymer Engineering and Science, Montanuniversitaet Leoben, Austria
Abstract: Styrene-isoprene-styrene (SIS) block copolymer/carbon nanotubes composite was prepared by deep casting method. The specimen was prepared by dipping of the copper interdigitated electrode into the SIS/carbon nanotubes or graphene dispersion in toluene. The Kraton D SIS is thermoplastic elastomers with a combination of high strength, low hardness and low viscosity for easy thermoplastic processing in solution state. Presented work is motivated by the fact that carbon nanotubes and graphene have high surface area. Due to this fact carbon nanotubes or graphene can easily adsorbed or desorbed gaseous/vapors molecules. Carbon nanotubes/graphene also play important role in the electrical path creation because of their electrical conductivity. Another motivation for presentation this results is the fact that volatile organic compound in the form of vapors, solvent, or gases are widely used in the industry and could be potentially danger for human. We report the preparation and testing the sensing element for volatile organic compound on the base of Styrene-isoprene-styrene (SIS) block copolymer/carbon nanotubes or (SIS) block copolymer/graphene. The sensing element is made by easy dipping method. By this way was reached very thin, sensitive and homogenous layer. The sensor was testing for crude oil vapors delivered from Slovnaft. The crude oil was chosen according to their ability to swelling the (Styrene-isoprene-styrene) (SIS) block copolymer matrix. This type of crude oil contains a lot of volatile residue. The testing crude oil is in the form of saturated vapors. Also the influence of graphene sheets size for sensitivity response was measured.
Acknowledgements: The work was supported by Ministry of Education, Youth and Sports of the Czech RepublicProgram NPU I (LO1504)and by project VEGA 2/0119/12.
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Hue-Min Wu, Chinese Culture University, Optoelectric Physics, Taiwan
Abstract: Functional single-walled carbon nanotubes (SWNTs) exhibit a unique combination of excellent mechanical, electrical and electrochemical properties, which has stimulated increasing interest in the application of SWNTs as components of biosensors. Considerable advancement has been made toward their synthesis and processing to fabricate molecular devices such as field-effect transistors. This progress has led to the recent emergence of bio/abio hybrid technology that bridges the sciences of CNTs and biology by pairing the advantages of CNTs and biological materials, such as DNA and proteins. However, one of main challenges is imaging in the reaction environment with resolution down to nanometer scale for noninvasive monitoring of the biomolecule. One the hand, although CNTs could be manipulated by using and atomic-force microscope tip, it is still difficult to handle or align individual CNTs to ideal locations. In this research, we report a simple and general approach to π-π stacking functionalization of the sidewalls of SWNTs by 1-pyrenebutanoic acid, succinimidyl ester (PSE), and subsequent immobilization of insulin-like growth factor 1 receptor (IGF1R) onto SWNTs with a high degree of control and specificity. The selection of PSE provides visualization and characterization of individual CNTs based on its strong luminescence. In addition, we designed a simple and efficient electrode with a staggered pattern to increase the effect of electrophoresis by using electric field for the macroscopic alignment of SWNTs to complete a field-effect device for CNT-based biosensors. The results of four-point probe method demonstrated high sensitivity of detection. The functional of SWNTs was investigated by Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Raman spectroscopy. By the biological techniques of cell culture and immunofluorescence (IF), the IGF1-R probes and IGF1 of MCF-7 breast cancer cells released from binding scenario can be detected qualitatively. Using the method of enzyme linked immunosorbent assay (ELISA) with the corresponding current change of the probe, the concentration of IFG1 can be measured quantified. Combining these bio-technologies, identification of biological specific can be more reliable.
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Amtuljamil Sami, University of the Punjab , Institute of Biochemistry and Biotechnology, Pakistan
Abstract: Congo red is an anionic dye, heavily used in textile as dying agent. As a result, it is present as the contaminant in the wastewater released from the textile mills. Researchers are in search of economically efficient and convenient methods for the removal of Congo red from the industrial wastewater that could be recycled after removing the carcinogen. The study was conducted, aiming the application of hydrogels based on chitosan/acrylamide alloy and Graphene oxide (GO) for water purification system. Graphene was prepared from used battery cells and used as starting material for GO. The alloys were cast in molds with a composition of 1.2% chitosan, 4.0% acrylamide in the presence of bis-acrylamide, a cross-liking agent, and GO. A fixed amount of glycerol was added as a plasticizer. Experimental studies were carried out at room temperature at pH 7.0. Results imply that under the standard conditions, 200mg of Congo red was removed by one gram of chitosan present in the hydrogels. A comparative study of hydrogels with and without GO was also carried out. It was inferred that addition the of GO to the hydrogels increase tensile strength to the hydrogels and provide stability to the membrane during the process. Kinetics of the reaction was also studied. Swelling properties of the hydrogels were also compared at different pH values. Earlier different workers had used chitosan beads for the removal of Congo red for wastewater treatment. The extraction of used beads after treatment could be laborious. The use of hydrogels could have an advantage over this method as stable hydrogels could be removed conveniently. This report shows that the use of hydrogels is economical and efficient in removing dyes from the industrial water waste, under mild conditions.
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Mohaned Mohamed, Missouri University of Science and Technology, Mechanical Department , United States
Abstract: Composite sandwich structures have been extensively employed in aerospace structures, ship, and infrastructure, due to their advantages such as corrosion resistance, light weight and high strength to weight ratio. The understanding of their behavior under low velocity impact conditions is extremely important for the design and manufacturing of these engineering structures since these problems are directly related to structural integrity and safety requirements. Two-part thermoset Polyurethane (PU) resin system has been observed to have better mechanical properties and higher impact strength when compared to conventional resin systems such as polyester and vinyl ester. Vacuum assisted resin transfer molding (VARTM) is one of the commonly used low cost composite manufacturing processes. This study investigated the damage behavior of composite sandwich structures manufactured using the VARTM process with polyurethane resin and two different foam cores, rigid PU 6 lb density and Webcore (TYCOR-W) respectively, under transverse impacts at low velocities. Based on the load and energy histories, parameters including maximum load, penetration depth, and total energy absorbed have been investigated under three different impact energy levels (30J, 40J, and 50J) using a Dynatup drop tower Intron impact machine. The results show that the Webcore sandwich composite had 12% less damage done to the core than the rigid.
Acknowledgements: N/A
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SABRINA NAAMA, Research Center in Semi-conductors Technology for Energetic (CRTSE). 2, Bd. Frantz Fanon, B.P. 140 Alger-7 Merveilles, Alger, Algeria, TESE, Algeria
Toufik Hadjersi, Research Center in Semi-conductors Technology for Energetic (CRTSE). 2, Bd. Frantz Fanon, B.P. 140 Alger-7 Merveilles, Alger, Algeria, TESE, Algeria
Hamid Menari, Research Center in Semi-conductors Technology for Energetic (CRTSE). 2, Bd. Frantz Fanon, B.P. 140 Alger-7 Merveilles, Alger, Algeria, , Algeria
SABRINA Lamrani, Research Center in Semi-conductors Technology for Energetic (CRTSE). 2, Bd. Frantz Fanon, B.P. 140 Alger-7 Merveilles, Alger, Algeria, TESE, Algeria
Ghania Nezzal, USTHB, LPT, FGMGP. BP 32, El Alia, Bab Ezzouar, 16111 Alger, Algeria, , Algeria
Abstract: Organic dyes contaminants present in industrial waste water are of major concern with respect to the health of the general public. Tartrazine is one of organic pollutants and is an azo dye its degradation was very few studied. Up to now, the degradation was investigated mainly in the presence of H2O2 in aqueous solution. The application of semiconductors in heterogeneous photocatalysis based on the advanced oxidation process, to eliminate various pollutants in aqueous systems as well as in the air has gained significant attention in the last decade. Indeed, recently it was well shown that silicon nanowires are efficient for the degradation of the Rhodamine B. In this work we investigated the photodegradation of tartrazine by silicon nanowires (SiNWs) without presence of H2O2. SiNWs were elaborated with a chemical method termed metal-assisted electroless etching. SiNWs modified with copper was also experimented as catalyst in the degradation of tartrazine. Also, the effect of copper concentration has been studied for the degradation of tartrazine. The photodegradation of tartrazine was monitored by UV-VIS spectroscopy and the diffraction spectra were obtained by means of a diffractometer. The results show that the photodegradation of tartrazine depend strongly on parameters studied and follows the pseudo-first-order reaction.
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Laurent Schlur, NS3E (CNRS), , France
Thomas Cottineau, ICPEES, , France
Karine Bonnot, NS3E, , France
Valérie Keller, ICPEES, , France
Denis Spitzer, NS3E, , France
Abstract: The goal of this work is to develop nanostructured sensors that permit to lower the detection limit of explosive vapors in order to strengthen the homeland security in public places. To reach this objective we decided to use silicon or silicon nitride cantilevers as transducers. Indeed the adsorption of molecules of explosives on a cantilever modifies its resonant frequency. So the detection of explosives is possible by studying the resonant frequency shift or the bending of cantilevers. In order to enhance the cantilevers sensitivity, their surfaces were nanostructured with metal oxide nanotubes or nanorods arrays. This nanostructuration increases the cantilevers surface area and consequently improves their explosives capture probability. The NS3E laboratory, in collaboration with the ICPEES laboratory, has developed and optimized several metal oxide nanorods and nanotubes syntheses. Titanium dioxide (TiO2), cupric oxide (CuO) and zinc oxide (ZnO) are for the moment the 3 different metal oxides nanostructured by these 2 laboratories. These nanostructures were first grown on cantilevers having an optical readout and in a second time the syntheses were adapted to piezoresitive cantilevers in order to avoid all problems link with the use of a laser. The objective is to determine the optimal size (length and diameter) of the nanostructures in order to decrease the explosives detection threshold down to unprecedented values. That’s why different sizes of each metal oxide were obtained by tuning the reaction time, the temperature, the sample position in the reactor and the concentration of the reagents. These nanostructured sensors are able to detect several explosives (TNT, RDX, PETN,...) and the detection threshold is decreased to unprecedented. Indeed, these sensors are able to detect a concentration of 1 ppt of TNT.
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Oguzhan OZER, Kahramanmaras Sutcu Imam University, Elbistan Vocational High School, Turkey
Oguzhan OZER, Kahramanmaras Sutcu Imam University, Elbistan Vocational High School, Turkey
Zafer OZER, Mersin University, Mersin Vocational High School, Turkey
Muharrem KARAASLAN, Iskenderun Technical University, Electrical-Electronical Engineering, Turkey
Amirullah MAMEDOV, Bilkent University, Nanotechnology Research Center (NANOTAM), Turkey
Ekmel OZBAY, Bilkent University, Nanotechnology Research Center (NANOTAM), Turkey
Abstract: In the present work the acoustic band structure of a two-dimensional (2D) phononic crystal (PC) containing composite material were investigated theoretically and numerically by the finite element method. Two-dimensional PC with triangular and honeycomb lattices composed of composite cylindrical rods embedded in the air and liquid matrix are studied to find the existence of stop bands for the waves of certain energy. This phononic bandgap - forbidden frequency range - allows sound to be controlled in many useful ways in structures that can act as sonic filters, waveguides or resonant cavities. Phononic band diagram ω=ω(k) for a 2D PC, in which non dimensional frequencies ωa/2πc (c-velocity of wave) were plotted versus the wavevector k along the Г-X-M-Г path in the were investigate band structure, transmission of acoustic waves in two dimensional phononic crystals made of composite rods assembled in air with triangular and honeycomb lattice by experimentally and numerically, negative refraction and focusing of acoustic wave in composite rods assembled in water with same lattice by numerically. The measured transmission spectra show that the proposed structure has complete band gap. The flat bands and the polarization aspect of the associated eigenmodes is also discussed. Band structure and transmission spectra of triangular and honeycomb lattice phononic crystals with same cylinder radius and lattice parameters are compared. The variation of these band gaps with filling factor gave the largest gaps for all configurations for a filling fraction around f=0.5. We also investigate the negative refraction properties of 2D phononic crystal which is placed periodically composite cylinders in water by numerically. The negative refraction is observed in case of the direction of the group velocity and wave vector are antiparallel to each other owing to circular equifrequency contours.
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Oguzhan OZER, Kahramanmaras Sutcu Imam University, Elbistan Vocational High School, Turkey
Zafer OZER, Mersin University, Mersin Vocational High School, Turkey
Muharrem KARAASLAN, Iskenderun Technical University, Electrical-Electronical Engineering, Turkey
Amirullah MAMEDOV, Bilkent University, Nanotechnology Research Center (NANOTAM), Turkey
Ekmel OZBAY, Bilkent University, Nanotechnology Research Center (NANOTAM), Turkey
Abstract: In the present work the acoustic band structure of a two-dimensional (2D) phononic crystal (PC) containing composite material were investigated theoretically and numerically by the finite element method. Two-dimensional PC with triangular and honeycomb lattices composed of composite cylindrical rods embedded in the air and liquid matrix are studied to find the existence of stop bands for the waves of certain energy. This phononic bandgap - forbidden frequency range - allows sound to be controlled in many useful ways in structures that can act as sonic filters, waveguides or resonant cavities. Phononic band diagram ω=ω(k) for a 2D PC, in which non dimensional frequencies ωa/2πc (c-velocity of wave) were plotted versus the wavevector k along the Г-X-M-Г path in the were investigate band structure, transmission of acoustic waves in two dimensional phononic crystals made of composite rods assembled in air with triangular and honeycomb lattice by experimentally and numerically, negative refraction and focusing of acoustic wave in composite rods assembled in water with same lattice by numerically. The measured transmission spectra show that the proposed structure has complete band gap. The flat bands and the polarization aspect of the associated eigenmodes is also discussed. Band structure and transmission spectra of triangular and honeycomb lattice phononic crystals with same cylinder radius and lattice parameters are compared. The variation of these band gaps with filling factor gave the largest gaps for all configurations for a filling fraction around f=0.5. We also investigate the negative refraction properties of 2D phononic crystal which is placed periodically composite cylinders in water by numerically. The negative refraction is observed in case of the direction of the group velocity and wave vector are antiparallel to each other owing to circular equifrequency contours.
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Pengfei Tian, Southwest Jiaotong University, School of Materials Science and Engineering, China
Jun Lyu, Southwest Jiaotong University, Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, China
Rui Huang, Sichuan University, College of Polymer Materials Science and Engineering, China
Chaoliang Zhang, Sichuan University, West China Hospital of Stomatology, China
Abstract: Piezoelectric one- (1D) and three-dimensional (3D) hybrid micro/nanostructured materials have received intense research interest because of their ability in capturing trace amounts of energy and transforming it into electrical energy. In this work, a size-distributed graphene oxide (GO) was utilized for the concurrent growth of both the 1D nanowires and 3D micro/nanowire architectures of poly (vinylidene fluoride) (PVDF) with piezoelectricity. The in situ formation of the polymeric micro/nanostructures, with crystalline beta phase, was achieved by the high-pressure crystallization of a well dispersed GO/PVDF composite, fabricated by an environmentally friendly physical approach. Particularly, by controlling the crystallization conditions of the binary composite at high pressure, the melting point of the polymeric micro/nanowires, which further constructed the 3D micro/nanoarchitectures, was nearly 30oC higher than that of the original PVDF. The large scale simultaneous formation of the 1D and 3D micro/nanostructures was attributed to a size-dependent catalysis of the GOs in the pressure-treated composite system. The as-fabricated heat-resistant hybrid micro/nanoarchitectures, consisting of GOs and piezoelectric PVDF micro/nanowires, may permit niche applications in self-powered micro/nanodevices for energy scavenging from their working environments.
Acknowledgements: Supported by the National Natural Science Foundation of China (51373139).
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KWANHAN YOON, Kumoh National Institute of Technology, Energy and Chemical Engineering, Korea, Republic of
Young Sil Lee, Kumoh National Institute of Technology, , Korea, Republic Of
Byung Gil Min, Kumoh National Institute of Technology, , Korea, Republic Of
Abstract: For the application of the touch screen panel for the flexible display high transmittance and electrical conductive film is required. To enhance optical properties and surface conductivity of carbon nanotube (CNT)/silver nanowire/polyethylene terephthalate (PET) hybrid film, inorganic overcoating has been applied by roll-to-roll coating processing. The maximum transmittance of the hybrid film without washing and overcoating was less than 90%. The optimum thickness of the overcoating has been determine as 10 micro meter for the highest total transmittance, 92 %, while the sheet resistance of the hybrid film is 180 ohm/sq. For the further enhancement of the sheet resistance of the CNT/silver nanowire hybrid film to get less than 80 ohm/sq the thickness of the overcoating has been controlled as 30 micro meter, while the transmittance is more than 90%. The overcoating of nanoparticle can highly reduce the surface roughness of the CNT/silver nanowire hybrid film and enhance the optical clarity such as the total transmittance and the haze of the hybrid film. This work has been done using large scale roll-to-roll coating machine for the scalable product of the high performance flexible transparent conductive film.
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Ajeet Kumar, University of Hyderabad, School of Physics, India
K.C. James Raju, University of Hyderabad, School of Physics, India
A.R. James, Defence Metallurgical Research Laboratory, CCG, India
Abstract: The overall electrical properties of piezoelectric PZT materials can be enhanced by substituting La3+ ions at A-sites of its ABO3 structure. Substitution of donor dopant La+3 at the A-sites of the perovskite PZT, results in the softening of piezo-ceramics due to enhanced ease of reorientation of dipoles upon application of an electric field; thereby greatly enhancing electronic properties. Different compositions of (Pb1-xLax)(Zr0.60Ti0.40)O3 were studied for the same. In the next step, the high energy milling parameters (milling time and vials) were varied to get the maximum piezo response. In this study 8% La substituted PZT ceramics termed as PLZT 8/60/40 that were milled for 5 hours with Zirconia vial followed by cold isostatic pressing and sintered at 1200oC, shows optimum properties. XRD patterns, SAXS data, TEM and SEM images were used for microstructural and morphological investigation; which confirmed the perovskite phase, particle size of milled powders~25 nm, the grain size of sintered compact ~1.3 µm with a density of ~98%. Dielectric measurements suggest that the lanthanum substitution resulting in the deviation of nature of ferroelectric phase transition from normal to the diffuse type. Ferroelectric hysteresis loops (P-E and S-E) were measured and the highest value of a remnant polarization and strain were found to be ~34 µC/cm2 and ~0.31%, respectively with a low coercive field of ~11 kV/cm. To get the maximum piezoelectric properties, poling parameters (poling electric fields, time and temperature) of PLZT ceramics were also studied. Poled ceramic samples were used to determine the piezoelectric charge coefficient (d33) and the electromechanical coupling factor (kp). PLZT ceramics show an ultra high d33 of ~700 pC/N and kp ~0.75%.
Acknowledgements: Mr. Ajeet Kumar would like to thank DRDO for the financial support in the form of senior research fellowship (S.R.F.) to carry out this work and express their gratitude to the Director, DMRL for his interest in this work.
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Igor Golovin, National University of Science and Technology "MISIS", Moscow, , Russian Federation
Abstract: I.S. Golovin1*, А.M. Balagurov2, V.V. Palacheva1, I.A. Bobrikov2 1 National University of Science and Technology “MISIS”, Leninsky ave. 4, 119049 Moscow, Russia 2 Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia Over the past decades, the Fe-Ga ‘Galfenol’ alloys have been the focus of much attention due to their good mechanical properties and high magnetostriction; in addition, they have the potential to be widely used in magnetostrictive actuators and sensor devices. Neutron diffraction and mechanical spectroscopy techniques were applied to study phase transitions in Fe-Ga alloys with 23-25 and 26-27 at.% Ga. The following sequences of phase transitions at instant heating and subsequent cooling in the 20 - 900°C temperature range were recorded: D03  L12 (limited amount)  B2 was recorded at heating and B2  D03 at cooling for Fe-24Ga alloy, and the D03  L12  D019  A2(B2) was recorded at heating and A2(B2)  L12 at cooling for Fe-27Ga alloy. These transition sequences determine different temperature dependencies of elastic and anelastic properties. Apart from several thermally activated relaxation peaks with the Arrhenius parameters (activation energies of 1.05 and 1.85 eV and a pre-factor 0  10-15 s) featuring a Snoek-type and Zener relaxation, respectively, anelastic effects accompany phase transitions from bcc-born D03 to fcc ordered L12 phase, from L12 to hcp ordered D019 phase, and from D019 to A2 phase. The D03  A2 transition does not lead to a well-pronounced anelastic effect; in contrast, the D03  L12 transition generates internal stresses due to a different rate of an increase in the lattice parameter with temperature, and leads to a pronounced transient internal friction effect. The transient peak is unambiguously shown to indicate diffusionless features of the D03  L12 phase transition. At room temperature Fe-Ga alloys exhibit rather high damping capacity, which increases with an increase in Ga content up to ~19 at.% (specific damping capacity up to 30% at forced bending vibrations), then it becomes lower at Ga > 20%, and again reaches maximum at Ga content 27 at.%. The main contribution to damping comes from magnetomechanical damping: the L12 phase suppresses damping. In most cases there is a correlation between magnetosctriction values, magnetic structure, and damping. The absolute values of damping depend on test methods: forced vibration tests give lower damping compared to free decay tests, cantilever clamping decreases damping compared to three-point bending tests, static stress decreases damping and shifts maximum to higher amplitude of vibrations. References: I.S. Golovin, V.V. Palacheva, A.I. Bazlov et at. JALCOM 656 (2016) 897-902 I.S. Golovin. Materials and Design. 88 (2015) 577-587 I.S. Golovin, V.V. Palacheva, A.I. Bazlov et al. JALCOM 644 (2015) 959-967 I.S. Golovin, V.V. Palacheva, V.Yu. Zadorozhnyy et al. Acta Materialia, 78 (2014) 93–102
Acknowledgements: This work was supported by the Ministry of Education and Science of the Russian Federation in the framework of the Program aimed to increase the competitiveness of the National University of Science and Technology “MISiS” (№ К1-2015-026).
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Yongbeom Kim, dongguk-university, department of electronic and electrical engineering, Korea, Republic of
Joonhyeon Jeon, dongguk university, , Korea, Republic Of
Abstract: Zinc-Bromine flow Batteries (ZBBs) provide advantages of having cost effectiveness, high energy density, high cell voltage, high long cycle life, low cost of maintenance, for energy storage system. The predominantly aqueous electrolyte is composed of an aqueous zinc-bromide salt dissolved in distilled water and is stored in two external tanks. During charging and discharging the negative electrode reaction is the reversible dissolution/ plating of zinc, while at the positive electrode bromine is reversibly reduced to bromide. The overall cell reaction is as follows: Zn(s) + Br2(aq)  2Br-(aq) + Zn2+(aq). The ZBB is an attractive and useful technology for large-scale energy storage due to its higher energy density. However, the zinc deposition on the negative electrode takes place by unbalanced reaction rate between zinc and bromine elements, resulting in low coulombic efficiency. This is due to the fact that two substances in zinc and bromine half-cells undergo different phase transitions-i.e., liquid-to-solid and solid-to-liquid reactions on zinc negative electrode during charging and discharging, while liquid-to -liquid reactions on bromine positive electrode. Hence, a novel cell-architecture is needed to improve the coulombic efficiency of the ZBB. This paper describes a ZBB with an antisymmetric cell structure, which uses anode and cathode with different surface morphologies, for high-discharge capacity and reliability. The structure of the antisymmetric ZBB cell contains a carbon-surface electrode and a carbon-volume electrode in zinc and bromine half cells, respectively. To demonstrate the effectiveness of this proposed ZBB cell structure, Cyclic Voltammetry measurement is performed on a graphite foil and a carbon felt which are used as the surface and electrodes. Charge and discharge cyclic operations are also carried out with symmetric and antisymmetric ZBB cells combined with the two electrode types. Experimental results show that the arrangement of antisymmetric cell structure in ZBB provides a solution to the high performance and durability. This new approach allows more affordable ZBB systems to be built, and it helps solve limited design problems due to obtaining desired ZBB.
Acknowledgements: This work (Grants No. C0351608) was supported by Business for Cooperative R&D between Industry, Academy, and Research Institute funded Korea Small and Medium Business Administration in 2016.
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Jiri Matyas, Tomas Bata University in Zlin, Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Czech Republic
Petr Slobodian, Tomas Bata University in Zlin, Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Czech Republic
Robert Olejnik, Tomas Bata University , Centre of Polymer Systems, University Institute, Czech Republic
Abstract: A most of portable devices, such as mobile phones, tablets, uses antennas made of cupper. In this paper we demonstrate possible use of electrically conductive polymer composite material for such antenna application. Here we describe the method of preparation and properties of the carbon nanotubes (CNTs)/poly(ethylene octane) as flexible microstrip antenna. Carbon nanotubes dispersion in poly(ethylene octane) toluene solution were prepared by ultrasound finally coating PET substrate by method of dip-coating. Main advantages of PET substrate are low weight and also flexibility. The final size of flexible microstrip antenna was 5 x 50 mm with thickness of 0.48 mm (PET substrate 0.25 mm) with the weight of only 0.4028 g. Antenna operates at three frequencies 1.66 GHz (-6.51dB), 2.3 GHz (-13 dB) and 2.98 GHz (-33.59dB).
Acknowledgements: The work was supported by Ministry of Education, Youth and Sports of the Czech RepublicProgram NPU I
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Petr Slobodian, Tomas Bata University in Zlin, Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Czech Republic
Jiri Matyas, Tomas Bata University in Zlin, Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Czech Republic
Robert Olejnik, Tomas Bata University , Centre of Polymer Systems, University Institute, Czech Republic
Silvia Pertegas, Christian Doppler Laboratory for High Efficient Composite processing, Department Polymer Engineering and Science, Montanuniversitaet Leoben, Austria
Ralf Schledjewski, Christian Doppler Laboratory for High Efficient Composite processing, Department Polymer Engineering and Science, Montanuniversitaet Leoben, Austria
Abstract: This work describes the preparation technique and testing method of multi-functional glass reinforced epoxy laminates with embedded carbon nanotubes (CNTs) network with strain detection ability. It was found that straining of this structure leads to reversible increase of its macroscopic resistance with sensitivity to strain defined by gauge factor GF ~ 2.4. GF. This new functionality was further increased by CNTs proper oxidation using acidic KMnO4 agent reaching enhanced value of GF ~ 5.9. This improvement can be explained in terms of increased CNTs network contact resistance of tunnelling kind when applied strain leads to sharp contact resistance changes in CNTs junctions for oxidized tubes compared to non-treated one.
Acknowledgements: This work was supported by the OeAD, the Austrian Agency for International Mobility and Cooperation in Education Research in collaboraton with the Thomas Bata University in Zlín and by the Ministry of Education, Youth and Sports of the Czech Republic, under the project Czech-Austrian mobility (program KONTAKT II) project -7AMB16AT033, and by project of the Ministry of Education, Youth and Sports of the Czech Republic – Program NPU I (LO1504).
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Ghania FOURA, UNIVERSITE DE BEJAIA , FACULTE DES SCIENCES EXACTES, CHEMISTRY DEPARTMENT, Algeria
Ahcene SOUALAH, BEJAIA UNIVERSITY, FACULTY OF TECHNOLOGY, PROCESSING DEPARTMENT, Algeria
Abstract: In the present study, the effect of iron (0-10 at %) doped titania nano-photocatalyst supported on HY zeolites are synthesized via sol–gel method. The powders obtained were characterized by X-ray diffraction (XRD), MEB microscopy and Fourier-transformed infra-red spectra (FT-IR). The photocatalytic action of the different photocatalysts is tested with respect to the degradation of methylene blue in water solutions under UV and visible light irradiation. Firstly, the TiO2/HY catalyst exhibits the best photoactivity than the pure TiO2 under UV irradiation and another hand, the catalysts 10%Fe-TiO2/HY are more active than TiO2/HY. This improvement in activity was attributed to photoelectron/hole separation efficiency. The kinetics of the organics degradation is found to follow the Langmuir–Hinshelwood model.
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Amtuljamil Sami, University of the Punjab , Institute of Biochemistry and Biotechnology, Pakistan
Abstract: Amtul Jamil Sami, Madeeha Khalid, Sara Iqbal and Maira Afzal. Institute of Biochemistry and Biotechnology University of the Punjab Lahore 54594 Pakistan. Chitosan is a cationic biopolymer that is naturally abundant and non-toxic. Chitosan starch and chitosan Guar-gum based green gels were proven to be an effective method for wastewater treatment. The method employed used the principle of coagulation-flocculation. Green hydrogels were prepared by crosslinking chitosan with starch and chitosan with Guar gum using glutaraldehyde as a crosslinker. The mechanical stability and physical parameters of the green hydrogels were studied. The gels were further investigated for waste water treatment for removal of a toxic anionic dye Congo red. The anionic dye Congo red was taken in concentrations 1.45mM and 0.145mM respectively and treated with green gels at neutral pH overnight with 150 rpm orbital shaking. More than 90% dye removal was observed. The process mainly involved the flocculation of the dye. The hydrogels were able to remove commercial dyes as well. The results were confirmed by visible and FTIR spectroscopy. The possible mechanism of dye removal was charge neutralization of dye particle due to NH2 groups present on chitosan and Coagulation-flocculation property of chitosan. The present work could provide a basis of safe wastewaters treatment from textile and dying industry by using chitosan-based green hydrogels.
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Usung Park, Agency for Defense Development, The 3rd(SR) R&D Institute - 4, Korea, Republic of
Jaewook Rhim, Agency for Defense Development, The 3rd(SR) R&D Institute - 4, Korea, Republic Of
Jun Eon An, Agency for Defense Development, The 3rd(SR) R&D Institute - 4, Korea, Republic Of
Abstract: In this paper, an anchor design for silicon-on-glass (SOG) process which improves the uniformity of bonding strength is presented. SOG process with an electrode-patterned glass substrate is widely used as a standard fabrication process to form high-aspect-ratio movable silicon microstructure in various sensors including the inertial and resonant sensors. In the proposed anchor design, a trench between the silicon-bonded area and the electrode-contact area is introduced to separate them to prevent irregular bonding caused by the protrusion of the electrode layer beyond the glass surface. This technique can be conveniently adopted to almost all the devices fabricated by SOG process without additional processes. To evaluate the effectiveness of the proposed anchor design, shear stress test was conducted using fabricated devices. The structures with separated anchor showed considerably less deviation than the ones with conventional anchor in bonding strength and this deviation difference became severer when the bonding quality was degraded by post wet etching process.
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Alexander Pereyaslavtsev, VNIIA, Nanodiagnostics, Russian Federation
Igor Sokolov, VNIIA, Microelectronics, Russian Federation
Leonid Sinev, Dukhov Research Institute of Automatics (VNIIA), Microelectronics department, Russian Federation
Abstract: In this paper, we have decided to consider an alternative method of producing polycrystalline silicon and study the change of its electrophysical characteristics depending on process parameters. As an alternative low-pressure chemical vapor deposition (LPCVD) method appears aluminum-induced crystallization (AIC), which allows to obtain a polycrystalline silicon film is significantly larger grain size, thereby reducing the contribution of grain boundaries. A comprehensive study of polycrystalline silicon was carried out using a variety of microscopic (OM, SEM) and spectroscopic (RAMAN, XPS) and diffraction (EBSD, XRD) analytic methods. We also considered the possibility of self-doping in the AIC, the result of which was obtained polycrystalline silicon with different resistance. Additionally considered changes in temperature coefficient of resistance (TCR) depending on technological parameters of AIC process.
Acknowledgements: This work was carried out with the assistance of S Yu Loparev, General Director of Dukhov Research Institute of Automatics (VNIIA).
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Nursel Can, Yıldız Technical University, Department of Physics, Turkey
Ahmet Altındal, Yildiz Technical University, , Turkey
Abstract: Due to wide spread use of pesticides in agriculture, they are common species of water and food pollutants. Various analytical methods such as chromatography, high-performance liquid chromatography, and multivariate electronic spectroscopy have been developed for the pesticide analysis. Although these methods show high selectivity, sensitivity and allow discrimination of pesticides, these techniques are time consuming and often require expensive instrumentation. The rapid detection of pesticides in water environment has been the subject of recent studies. Their sensitivity and selectivity toward target molecules depends on the recognition element. Therefore, there is an increased interest on the development of new sensing layers targeting various organic/inorganic compounds including pesticides. In the present study, a novel phthalocyanine as sensitive materials for chemical sensors operating in liquid environment are described. The pesticide sensing performance of the new compound are characterized by using quartz crystal microbalance technique. The influence of the modifications made to the Pc core on the sensing properties are discussed. Results from this preliminary analysis indicated that spray pyrolysis thin film of newly synthesized ball-type phthalocyanines have good potential for pesticide sensing element.
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Mehmet Aköz, Yildiz Technical University, Dept. of Physics, Turkey
Mustafa Erkovan, Sakarya University, Department of Nanoscience and Nanoengineering, Turkey
Abstract: Magnetic sensors are optimum for all kinds of contactless position during the life. They can be used under different environmental conditions. This advantage has resulted for widespread using kinds of applications. Magnetic sensors based on Giant Magnetoresistance (GMR) and Exchange Bias (EB) effect. EB effect is used to pin a ferromagnetic layer which used as one of the ferromagnetic layer in GMR structures. EB effect is known that the exchange interactions at ferromagnetic/antiferromagnetic (FM/AFM) interface and was discovered in 1956 by Meiklejohn and Bean. It can be used as data storage medium due to its large magnetocrystalline anisotropy, and also is suitable to be used in read head device as FM layer. Regarding all these, we devoted this study on the EB properties of magnetron sputtered PtxCo1-x/CoO bilayers at UHV conditions, where x is from 0.1 to 0.5 by 0.1 steps. Thickness of FM and AFM layers were fixed at 10 nm for each sample and composition of PtCo layer was varied. We used X-ray Photoelectron Spectroscopy (XPS) for the chemical composition of both PtCo and CoO. Magnetic characterization of Magneto-Optical Kerr Effect technique was used for investigate direction of magnetization at room temperature firstly for each sample. The results show that all the sample have perpendicular magnetization. EB properties were examined using Vibrating Sample Magnetometer. Temperature dependent magnetization measurements indicate that strength and onset temperature of EB are enhanced by increased Pt concentration. As Pt concentration was 0.5, EB effect reached the maximum value, and then it began to decrease. Besides EB, Blocking Temperature (TB) had the same behavior. According to these results, the TB and EB effect can be controlled by Pt concentration.
Acknowledgements: This study was supported by TUBITAK under the Grant No. 212T217.
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Mehmet Aköz, Yildiz Technical University, Dept. of Physics, Turkey
Tarık Yılmaz, Duzce University, Department of Physics, Turkey
Oğuz Köysal, Duzce University, Department of Physics, Turkey
Mustafa Erkovan, Sakarya University, Department of Nanoscience and Nanoengineering, Turkey
Abstract: Magnetic sensors have been used for nearly two centuries. The first applications were mostly for direction finding. Magnetic storage in computers has become unlimited to be used with the start of the magnetic sensor are used in many industrial and navigation control systems. According to 2012 data, the nano-magnetic market has reached 6.9 billion dollars for a year. This budget is expected to be increased, when the commercialized products are felt in price. It is known that the rapidly developing sub-category for this sector is GMR sensor technology. Magnetic sensors utilizing Giant Magnetoresistance (GMR) effect in particular are used as magnetic sensors in magnetic recording media. Magnetic sensors using GMR effect are often called Spin Valve sensors. Giant Magnetoresistance (GMR) feature two ferromagnetic (FM) between the non-magnetic layer (NM) is observed when it comes to a conductive layer.When coupled to a FM, the magnetoresistence (change of resistence by the presence of a magnetic field) of such a system can increase drastically. This change in resistance is called “Giant Magnetoresistance” (GMR) and was first characterised by Fert et al. in 1988 [1]. GMR structure in the spin orientation can be changed. This situation due to resistance measurement should be made for fixing one of the spins in the FM layer. Exchange bias effects are used for the realization of this stabilization process. However, it was the reduction of the saturation fields to observe giant magnetoresistance (GMR) in exchange biased systems [2]. Exchange Bias (EB) effect which interactions between ferromagnetic (FM) and antiferromagnetic (AFM) layers was discovered in 1956 by Meiklejohn and Bean [3]. EB is very complex effect and varies different from material to material. Exchange bias is an essential aspect of many giant magnetoresistance (GMR) device structures including read heads, spin valves, spin tunnel junctions, and sensors, magnetic recording media. Nickel has perpendicular anisotropy in which the easy axis is close to the direction normal to the sample surface [4]. Body-centered cubic (fcc) structure in nickel at room temperature is one of three transition metal showing ferromagnetic properties, the easy magnetization axis in this type of structure {111} direction. It has ferromagnetic order at room temperature and the Curie temperature of nickel is around ~ 631 K. Besides CoO at room temperature is very close to Neel temperature is optimal for Exchange Bias effect monoxide. The observation of exchange bias effect with perpendicular magnetization is seldom found in literature. Increasing the exchange bias field by using magnetic multilayers would provide enhancement for the applicability to technology. In this study, our goal was that EB effect between having multilayer of Ni (FM layer) and CoO (AFM layer). [Ni/CoO]x (x changes from 1 to 5) multilayer samples were grown at Ultra High Vacuum (UHV) conditions by Magnetron Sputtering Deposition technique. Ni/CoO multilayers with 22 Å of nickel thickness, which were found to exhibit perpendicular magnetization [5] were prepared and examined in terms of EB effect and blocking temperature. CoO layer thicknessis fixed at 20 Å for both samples [5]. The thickness is important for magnetic properties, the deposition rate must be well-controlled. For the purpose that thickness calibration was performed by using X-ray Photoelectron Spectroscopy (XPS). We had used Magneto-Optical Kerr Effect (MOKE) technique to determine perpendicular magnetization at room temperature before investigating the EB properties of the samples in Vibrating Sample Magnetometer (VSM).Since the Néel temperature of AFM CoO layer is around 290 K, Ni/CoO multilayer films were heated up to 320 K before cooling down to the measurement temperature to observe EB effect for each sample. After that depending on the magnetic field we measured between 10 K–300 K and determine EB and blocking temperature. References: [1] M. N. Baibich, J. M. Broto, A. Fert, F. Nguyen Van Dau, F. Petroff, P. Etienne, G. Creuzet, A. Friedrich, and J. Chazelas. Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices. Phys. Rev. Lett., 61(21):2472, 1988. [2] B. Dieny, V.S. Speriosu, S.S.P. Parkin, B.A. Gurney, D.R. Wilhoit, D. Mauri, Phys. Rev. B 43 (1991) 1297 [3] Meiklejohn W. H. And Bean C. P., New Magnetic Anisotropy, Phys. Rev.,102 (5), 1413, 1956. [4] B. Schulz, K. Baberschke, Physical Review B 50 (1994) 13467. [5] Parlak U., Aköz M. E., Tokdemir Öztürk S., Erkovan M., Thickness Dependent Magnetic Properties of Polycrystalline Nickel Thin Films, ACTA Physica PolonicaA, 127, 995 – 997, 2015.
Acknowledgements: This study was supported by Research Fund of TUBITAK under the Grant No. 114F004 and Duzce University.
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Mehmet Aköz, Yildiz Technical University, Dept. of Physics, Turkey
Baha Sakar, Gebze Technical University, Department of Physics, Turkey
Umut Parlak, Peter Grünberg Institut, Electronic Properties (PGI-6), Germany
Osman Öztürk, Gebze Technical University, Department of Physics, Turkey
Osman Öztürk, Gebze Technical University, Department of Physics, Turkey
Mustafa Erkovan, Sakarya University, Department of Nanoscience and Nanoengineering, Turkey
Abstract: Today's electronic technology has been developed as a silicon-based. Because of the fragile nature of Silicon wafer is not suitable for the human body as wearable. Besides these another problem for silicon-based electronics is the high cost. In the light of these, nowadays most of researches focus on flexible base structures because of low cost, flexibility etc. This study is focused on Exchange Bias Effect which is crucial poinf of Giant Magnetoresistance sensors. Magnetic sensors based on two significant effects; Giant Magnetoresistance (GMR) and Exchange Bias (EB) effect. This kind of sensor structure contains two ferromagnetic, a non-magnetic and an antiferromagnetic layers. EB effect is used to pin one of the ferromagnetic layers. The second ferromagnetic layer is free layer to sense the external magnetic field. On the other hand, the second ferromagnetic layer is pinned by EB effect because of that the second ferromagnetic layer is not effected by the external magnetic field. As the free layer senses the external field, the resistivity between two ferromagnetic layers change and in this way the external magnetic field can be sensed by GMR based magnetic sensors. EB effect is known that the exchange interactions at ferromagnetic/antiferromagnetic (FM/AFM) interface and was discovered in 1956. It is caused two significant effects on a field cooled FM/AFM system. Particularly, coercive field of FM layer is enhanced and hysteresis loop is shifted along the applied field axis. We devoted this study on the EB properties of magnetron sputtered Co/CoO bilayers on flexible PET (Polyethylene terephthalate), where Co thickness is from 5 Å to 20 Å by 5 Å thickness steps. Thickness AFM layers were fixed at 20 nm for each sample and thickness of Co layer was varied. First step of magnetic characterization Magneto-Optical Kerr Effect technique was used for investigate easy-axis magnetization at room temperature. EB properties were examined using Vibrating Sample Magnetometer. Temperature dependent magnetization measurements indicate that strength and onset temperature of EB are enhanced by increased Co thickness. These results show that TB and EB effect can be controlled by Co thickness. Last step of our study will be about spin dynamics, this part of study is on-going.
Acknowledgements: This work was supported by Research Fund of Gebze Technical University.
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Hyon Chol Kang, Chosun University, Department of Materials Science and Engineering, Korea, Republic of
Abstract: Tin Oxide(SnO2) has been widely investigated as a transparent conducting oxide (TCO) and can be used in optoelectronic devices such as solar cell and flat-panel displays. It would be applicable to fabricating the wide bandgap semiconductor because of its bandgap of 3.6 eV. In addition, SnO2 is commonly used as gas sensors. In this study, a powder sputtering method was empolyed to grow high quality epitaxial SnO2 thin films, in contrast to typical sputtering technique with sintered target. Single crystalline sapphire(0001) substrates were used. The samples were prepared with varying the growth parameters such as gas environment and film thickness. Then, the samples were characterized by using X-ray diffraction, scanning electron microscopy, and atomic force microscopy measurements. We found that the strain evolution of the samples was highly affected by gas environment and growth rate, resulted in the delamination under O2 environment. Meanwhile, the strain was relaxed and maintained constant during the growth under Ar gases. In addtion, a 9-micron-thick sample can be grown without delamination.
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Hyon Chol Kang, Chosun University, Department of Materials Science and Engineering, Korea, Republic of
Abstract: We report the effects of precursor concentration on the characteristics of ZnO nanostructures during hydrothermal processing. Self-perpetuating surface spirals are fabricated at concentrations of 0.25 and 0.5 M, with samples grown at concentrations of 0.05 and 0.125 M exhibiting ZnO nanorods. This can be explained by the change of growth mode from initial dendritic growth to screw dislocation-driven growth with decreased supersaturation. The screw dislocations nucleate at the V-shaped valleys of the dendrite boundaries during the intermediate stage. We demonstrate that continuous screw dislocation-driven growth leads to the formation of ZnO nanotubes having Burger's vectors of 1.45 nm.
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IBRAHIM GAIDAN, SIRTE UNIVERSITY, Electrical & Electronics Enginering, Libyan Arab Jamahiriya
Abstract: In this study three different compositions of ZnO and TiO2 were fired at 1250 C0. The samples were grinding to the powder which used as sensing materials. The samples were deposited on alumina substrates that had cupper electrodes to form three gas sensors. XRD was used to determine the final compositions of the samples. The three sensors were used to detect propanol at room temperature at two different concentrations. The first concentration range was from 500 to 3000ppm by increasing step 500ppm while the second concentration range was from 2500 to 5000ppm by increasing step of 500ppm.The response of the sensors was increasing as the gas concentration increased. The repeatability of the three sensors was studied and the results were reported.
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Farouk REZGUI, BEJAIA UNIVERSITY, FACULTY OF TECHNOLOGY, PROCESSING DEPARTMENT, Algeria
Ounissa SADOUN, BEJAIA UNIVERSITY, FACULTY OF TECHNOLOGY, PROCESSING DEPARTMENT, Algeria
Touffik BAOUZ, BEJAIA UNIVERSITY, FACULTY OF TECHNOLOGY, PROCESSING DEPARTMENT, Algeria
Sihem BOURICHE, BEJAIA UNIVERSITY, FACULTY OF TECHNOLOGY, PROCESSING DEPARTMENT, Algeria
Salem ZADI, BEJAIA UNIVERSITY, FACULTY OF TECHNOLOGY, PROCESSING DEPARTMENT, Algeria
Farida DJERADA, BEJAIA UNIVERSITY, FACULTE DES SCIENCES EXACTES, CHEMISTRY DEPARTMENT, Algeria
Nouria DJAMA, BEJAIA UNIVERSITY, FACULTE DES SCIENCES EXACTES, CHEMISTRY DEPARTMENT, Algeria
Abstract: Currently, numerous molecules stemming from the pharmaceutical research are not well developed because of their low efficiency, particularly also due to their low solubility in biological liquids, and to their inactivation/modification by the metabolism or the gastric acidity. Thus, the optimization of the galenic formulation is necessary to improve the therapeutic efficiency of the medicine, to reduce the unwanted side effects, and to bring comfort and security to the patient. The objective of this study consists in preparing a biodegradable polymer based microcapsules, poly(lactic acid), containing an hypertensive, valsartan, by using the emulsion-solvent evaporation method. To optimize the encapsulation parameters, design of experiments technique is adopted. Thus, a matrix of Box Behnken type is achieved with three independent variables namely, the surfactant concentration, the polymer quantity and the aqueous phase volume. The optimal formulation is then prepared with polycaprolactone (PCL) to study the effect of the nature of the polymer on the encapsulation ratio. The obtained microcapsules are characterized by various techniques including UV-visible, FTIR, XRD and SEM. The obtained results showed that the optimal formulation prepared with PLA presents an encapsulation ratio of 55%, whereas that obtained with the PCL presents an encapsulation ratio of 69%. The SEM analysis performed on the various formulations demonstrated that the microcapsules are spherical in shape and their size varies in the range between 2 and 44µm.
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Alexandre FAVARD, IM2NP CNRS, Microsensor, France
Abstract: The control and analysis of air quality have become a major preoccupation of the last twenty years. In 2008, the European Union has introduced a Directive (2008/50/EC) to impose measurement obligations and thresholds to not exceed for some pollutants, including BTEX gases (Benzene, Toluene, Ethylbenzene, Xylenes), in view of their adverse effects on the health. This Directive, for example, fixed at 2 ppb the Benzene annual average limit value. In this paper, we show the ability to detect very low concentrations of BTEX using a gas microsensor with metal oxide thin-film. A test bench able to generate vapor concentrations has been achieved and fully automated. Thin layers of metal oxides (WO3, ZnO) have been realized by reactive magnetron sputtering. These sensitive layers are functionalized with gold nanograins. Our sensors have been tested on a wide range of concentrations of BTEX and have been able to detect concentrations of a few ppb for operating temperatures below 300°C. These results are very promising for detection of very low BTEX concentration for indoor as well as outdoor application. The addition of gold on the sensitive layers decreases the operating temperature of the sensors and increases the response to BTEX gas. The best results are obtained with a sensitive layer based on zinc oxide (ZnO).
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Vasyl Petryshak, Lviv Polytechnic National University, Institute of Telecommunications, Radioelectronics and Electronic Engineering, Ukraine
Maria Vistak, Danylo Halytsky Lviv National Medical University, , Ukraine
Orest Sushynskyi, Lviv Polytechnic National University, ITRE, Ukraine
Zinoviy Mikityuk, Lviv Polytechnic National University, ITRE, Ukraine
Abstract: For nowadays the main goal for using the sensors are the investigations the new gas sensitive materials. Optical gas sensors are characterized by the most of the high response. Such sensors distinguished by the high sensitivity, selectivity and stability and have long-term operation. The principle of operation is based on the absorption of NH3 gas by sensitive element of primary transducer and changing the spectral characteristics. Principle of gas sensor operation is based on the registration of shift of the wavelength minimum in spectral characteristics of cholesteric-nematic mixture (CNM). In paper as sensitive material used the CNM on the basis of BLO-61 cholesteric liquid crystal (CLC) with 5CB nematic liquid crystal (NLC) doped by single and multiwall carbon nanotubes. The optimal nanocomposite structure composition to obtain the maximum value of spectral sensitivity coefficient was determined. In paper was found the increasing the nanotubes concentration in CNM leads to increasing the spectral sensitivity coefficient independently of 5CB concentration in CNM, but the maximum nanotubes concentration was chosen to take in to account the optical transparency of experimental samples.
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Djahida SIDANE, Université de Bejaia, Faculté de Technologie, Génie des procédés, Algeria
KHIREDDINE Hafit, University of Bejaia, Algeria, Process Engineering, Algeria
YALA Sabah, University of Bejaia, Algeria, , Algeria
Abstract: The aim of this paper is to investigate the effect of the addition of TiO2 inner-layer on the morphological and mechanical properties of hydroxyapatite (HAP) bioceramic coatings deposited on 316L stainless steel by sol-gel method in order to improve their properties of hydroxyapatite and expand its clinical application. The addition of TiO2 as sub-layer of a hydroxyapatite coating results in changes in surface morphology as well as an increase of the microhardness. The deposition of the inner-layer provides the formation of new types of hydroxyapatite coatings at the same condition of annealing. This represents an advantage for the various applications of the hydroxyapatite bioceramic in the medical field. Classical hardness measurements conducted on the coated systems under the same indentation load (10g) indicates that the microhardness of the HAP coating is improved by the addition of TiO2 inner-layer on the 316L stainless steel substrate. The hardness values obtained from both classical tests in microindentation and the continuous stiffness measurement mode in nanoindentation are slightly different. This is because nanoindentation is more sensitive to the surface roughness and the influence of defects that could be present into the material. Moreover, nanoindentation is the most useful method to separate the contribution of each layer in the bilayer coatings. In this study, the hardness is comparable with those reported previously for pure HAP ceramics (1.0–5.5 GPa) which are close to those properties of natural teeth.
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Solleti goutham, JNT UNiversity Hyderabad, Center for Nanoscience and Technology, India
Abstract: The clean and healthy environment is the increasing essential of the present society. The environment is getting polluted by increasing chemical plants, factories and vehicles. The hectic environmental pollution problems for analyze requires reliable, accurate, fast respond and selective solid-state sensors for monitoring and control damages. The present research is aimed at investigation on the phase purity and microstructure effect of Zn(x)Fe (1-x) 2O4 (X=0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9) nanoparticles with gradual increasing the concentration of Zinc percentage and their Liquid Petroleum Gas (LPG) sensing characteristic. A wide range of sensors based on Zn(x)Fe(1-x)2O4 metal oxide semiconductors has been developed, due to its high electrical and magnetic behavior. Nano size Zinc ferrite was synthesized by sol-gel auto combustion method. Recently a huge research on nanostructured ferrites synthesized by sol-gel auto combustion method has been carried out. The obtained powder are characterized by X-Ray diffraction (XRD), it illustrates the cubic structure of Zn(x)Fe(1-x)2O4 (x=0.5) and average crystallite size calculated. Scanning electron microscope (SEM) images shows mesoporous nature, Fourier transform infrared spectroscopy (FT-IR) techniques for the composition of the material and thermal analysis has been done by thermo gravimetric-differential thermal analysis (TG-DTA), UV-visible data shown optical characteristics of obtained Zn(x)Fe(1-x)2O4. Fabricated Zn(x)Fe(1-x)2O4 thin films by spin coating method and evaluated LPG 500 ppm sensing and its demonstrated.
Acknowledgements: This work is financial supported by the Department of Science and Technology-Science and Engineering Research Board, project no: SB/EMEQ-183/2013. Government of India. SG also thanks Science and Engineering Research Board for the award of JRF.
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Byung Gil Min, Kumoh National Institute of Technology, Materials Design Engineering, Korea, Republic of
KWANHAN YOON, Kumoh National Institute of Technology, Energy and Chemical Engineering, Korea, Republic of
Abstract: As the poor compressive strength of poly(p-phenylene benzobisoxazole) (PBO) fiber is known to be significant, modified PBOs were synthesized in poly(phosphoric acid) (PPA) by hybrid with nano-fillers such as graphene or carbon nanofibers (CNF) through in-situ polymerization. PBO and its hybrids were prepared by solution polymerization in poly(phosphoric acid) (PPA). The as-polymerized solutions of PBO and PBO/nano-fillers were transformed to their fibers through dry-jet wet spinning at a crystalline state. Compressive properties of mono filaments prepared from PBO and its hybrids could be successfully measured by Elastica loop test. It was found that the nano-fillers were significantly effective in improving compressive strength of PBO fibers by anchoring or piping effect.
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Kyriakos Christodoulou, University of Cyprus , Dpt. of Mechanical and Manufacturing Engineering, Cyprus
Afroditi Petropoulou, National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Photonics for Nanoapplications Laboratory and University of Peloponnese, Department of Informatics and Telecommunications, , Greece
Christos Riziotis, National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Greece
Mariliz Achilleos, University of Cyprus, Mechanical and Manufacturing Engineering, Cyprus
Epameinondas Leontidis, University of Cyprus, Chemistry, Cyprus
Christiana Polydorou, University of Cyprus, Mechanical and Manufacturing Engineering, Cyprus
Theodora Krasia-Christoforou, University of Cyprus, Mechanical and Manufacturing Engineering, Cyprus
Abstract: During the last years there has been an increased interest in the development of polymer-based optical sensors. Fluorescent polymer sensors belonging to the general class of optical sensors have been synthesized by introducing fluorescent moieties within a polymer matrix and have been successfully employed in the chemosensing of metal ions, anions and gases [1,2]. Herein we describe the fabrication and characterization of novel, fluorescent polymers in the form of (a) electrospun fibers and (b) semi-interpenetrating amphiphilic polymer networks containing the fluorescent homopolymer poly(anthryl-methyl methacrylate) (PAnMMA). The latter has been combined with the commercially available poly(methyl methacrylate) (PMMA) and with the in-house synthesized poly(2-dimethylamino) ethyl methacrylate (PDMAEMA) in the case of the electrospun fibers and polymer networks respectively. The blended PMMA/PAnMMA electrospun fibers have been evaluated as ammonia gas sensors [3] whereas the PAnMMA/PDMAEMA semi-IPN polymer networks have been tested towards their ability to act as metal ion sensors in solution. [1] H. N. Kim, Z Guo, W Zhu, J Yoon, H Tian, “Recent progress on polymer-based fluorescent and colorimetric chemosensors“, Chemical Society Reviews, vol. 40, 79-93, (2010) [2] S. W. Thomas, G. D. Joly and T. M.Swager, “Chemical Sensors Based on Amplyfying Fluorescent Conjugated Polymers”, Chemical Reviews, vol. 107, 1339-1386, (2007) [3] A. Petropoulou, K. Christodoulou, C. Polydorou, T. Krasia-Christoforou*, C. Riziotis* “Evaluation of cost-effective polymethacrylate-based electrospun fluorescent fibers towards ammonia sensing”, Journal of Fluorescence, under review.
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Cigdem Oruc, Yildiz Technical University, Physics, Turkey
Sevinc Guler, Yildiz Technical University, , Turkey
Ozgur Tekin, Yildiz Technical University, , Turkey
Ahmet Altındal, Yildiz Technical University, , Turkey
Abstract: The detection and quantification of potentially harmful bacteria, such as Escherichia coli (E. coli), crucial in a number of fields; disease diagnosis in medicine, pathogen detection in the environment, and food safety testing. Therefore, a great research challenge in this field is focused on the need to develop rapid, selective, specific, and sensitive methods to detect these bacteria. For sensor applications, nanoscale materials provide a large and often highly reactive surface area, which enables more effective capture and detection of molecules than bulk materials. In this manner, Porous Si (PS) has received significant attention for label-free biological sensing applications because of its high surface area, tunable pore sizes, and flexible surface chemistry for covalent and non-covalent attachment strategies. In this study, the sensing of E. Coli in liquid media with PS based sensor was investigated using impedance spectroscopy. The binding of target bacteria on the surface of PS was verified by a decrease in the real and imaginary parts of the comlex impedance. This impedance bio sensor was able to detect as low as 1.6×104 cells of E. coli in water samples. It was found that the magnitude of the impedance decay exponentially as the number of adhering cells increased. The total detection time from sampling to measurement was approximately 30 min. Equivalent circuit analysis indicated that the the electron transfer process, double layer capacitance, and dielectric capacitance were responsible for the impedance change due to the presence of E. coli on the surface of PS.
Acknowledgements: This work was supported by Yildiz Technical University of Turkey (Grant No: 2015-01-01-KAP03)
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Birsel Can Ömür, Yildiz Technical University, Physics, Turkey
Ahmet Altındal, Yildiz Technical University, , Turkey
Abstract: Among the molecular semiconductors used for gas sensors, phthalocyanines (Pcs) are the most widely used material due to the chemical and thermal stability of the planar aromatic ring system. These compounds offer a large variation of molecular properties, which can be tuned by synthetic modification. During the last decade, the sensing properties of the Pc based sensors toward both reducers and oxidants have been studied extensively. However, there have been limited work on the kinetics of ammonia adsorption onto the Pc thin film. The first aim of this study is, to clarify the effect of humidity on the ammonia sensing performance of oxo-bridged metallophthalocyanine thin film, second, to investigate the kinetics of ammonia adsorption and the effect of humidity on it. The results indicate the film of sensitive layer has good response, reversibility, stability, faster response, and recovery characteristic toward ammonia gas. It was also found that the presence of humidity modifies both the baseline conductivity and sensitivity of the film toward ammonia gas. In order to determine the best fit equation for this adsorption procesess, the rate constants, equilibrium capacities and related correlation coefficients for various kinetic models (the pseudo first- and second-order equations, Ritchie’s equation and the Elovich equation) were calculated and discussed. Our results indicated that the kinetics of ammonia adsorption onto this compound strongly depend on the presence humidity and ammonia concentration.
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Karima Bournane, University of Sciences and Technologie HOUARI BOUMEDIENNE, Algiers, Algeria
Abstract: The aim of this work is the comparison between Pt (Pd) / SiC-pSi and Pt (Pd) / PSC / SiC-pSi Schottky diode. The Schottky diode was characterized in air ambient and in vacuum at pressure 8.10-2 mbar. These diodes could be used for exhaust gas monitoring as gas sensors for different gas (O2, H2, CO, CO2 and hydrocarbure). The thin SiC layer are realized on p-type silicon (Si(100)) substrate by laser ablation method with KrF laser (248 nm) using 6H-SiC (purchased by Goodfellow UK) as sputtered target and a thermal deposition of a thin metal layer (Platinum (Pt) and Palladium (Pd)). The electrical measurements were made at room temperature 295 K using an oxford cryostat. We investigate the effect of nature of surface SiC and the nature of the metal on the electrical parameters such as ideality factor (n), barrier height and series resistance (Rs). Analysis of current-voltage (I–V) characteristics showed that the forward current might be described by classic thermal emission theory. The ideality factor of the I–V characteristics was found to be dependent and vary only on a modified surface such as PSC (interfacial layer) and also vary with the nature of the metal (Pt or Pd) for electrical measurements in air and in vacuum, it notes that Schottky diode without an interfacial layer (PSC), all electrical parameters does not change when the measurements were taking in vacuum or in air ambient.
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Ying-Pin Wu, Academia Sinica, Institute of Physics, Taiwan, Province Of China
Chia-Jung Chu, Academia Sinica, Institute of Physics, Taiwan
LiChu Tsai, Institute of Organic and Polymeric materials, National Taipei University of Technology, Taiwan, Province Of China
ChiiDong Chen, Academia Sinica, Institute of Physics, Taiwan
Abstract: We report on a technique that can extend the use of nanowire sensors to the detection of interactions involving nonpolar and neutral molecules. This technique makes use of the fact that molecular interactions result in a change in the permittivity of the involving molecules. For the interactions taking place at the surface of nanowires, this permittivity change can be determined from the analysis of the measured nanowire complex impedance. To demonstrate this technique, histidine with different charge polarities controlled by the solutions pH value was detected, including the detection of electrically neutral histidine at a sensitivity of 1 pM. Furthermore, it is shown that nonpolar molecules, such as hexane, can also be detected. The technique is applicable to the use of nanowires with and without surface insulating oxide. We show that the information about the changes in the amplitude and phase of the complex impedance reveals the fundamental characteristics of the molecular interactions, including the molecular field and the permittivity.
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Chang-Soo Han, Korea University, School of Mechanical Engineering, Korea, Republic Of
Abstract: The creative inspiration from biological ion channels have been much intrigued because of their unique and exquisite operational function in living cells. Specially, their extreme and dynamic sensing ability can be realized by the combination of decoupled receptors and nanopores. Here we demonstrated the artificial ion channels with high sensitivity and selectivity for pressure sensing, which was inspired in nature. Our ion channel for pressure detection was basically consisting of receptors and nanopore membranes, enabling dynamic current response from external force and multiple applications. The ion channel pressure sensors showed the sensitivity of ~ 5.6 kPa-1 and ~11 ms in response time at the frequency of 1 Hz. The power consumption was recorded less than a few μW. Reliability test was accomplished by 10,000 loading-unloading cycles. Also, linear regression was expressed in terms of temperature and there was no significant current signal variation in humidity test. The patchable ion channel pressure sensor was delivered for the detection of human blood pulses, which was recognized with clearly different signals for each person. In addition, the modified pressure ion channels can detect voltage signals for multi-motion like pressing and folding in a high pressure range (10~20 kPa) without power.
105
Chia-Jung Chu, Academia Sinica, Institute of Physics, Taiwan
Ying-Pin Wu, Academia Sinica, Institute of Physics, Taiwan, Province Of China
ChiiDong Chen, Academia Sinica, Institute of Physics, Taiwan
LiChu Tsai, National Taipei University of Technology, Institute of Organic and Polymeric materials, Taiwan
Abstract: Histidine is an amino acid that is commonly used as a tag for binding with Ni-NTA (nickel-nitrilotriacetic acid), which is a linking molecule for protein purification process. Histidine belongs to the family of zwitterion whose net charge varies with solutions pH value. At a specific pH value called the isoelectric point (pI=7.6), which is fairly close to the physiological pH in biology systems, histidine carries no net charge and is electrically neutral. Although silicon-nanowire field-effect-transistor (SiNW-FET) is an excellent candidate for detection of molecular interactions, the FET sensors detect changes in either molecular charge or dipole and are not capable of detecting the probe-target interactions that produce unmeasurable changes in either charge or dipole. Here, we propose and demonstrate a technique to detect the permittivity change due to histidine/Ni-NTA interaction using the alternative current measurement technique (AC technique). A systematic study in phosphate buffer solution (PBS) of various pH values was carried out. A comparison between the results of conventional DC and proposed AC techniques was made, showing capability of detecting interaction-induced permittivity change involving electrically neutral molecules using SiNW-FET based sensors.
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Koji Yamada, Saitama University, , Japan
Abstract: The enhancements of radiations from device surfaces are very important for electric machines and/or electronic devices to prevent from heating up, In this investigation, new applications of micro-scale membrane of Si, SiO2 etc.on the metal surfaces have been developed to cool down the temperature without breaking insulations of the devices. The modified black-body radiations were sensitively detected by the thermisters with sub-second responces. We attained the cooling effect (℃/s) by 20% in an Al-plate of 10cmx10cm with 0.5mmt. We successfully observed the detaching/ataching processes of molecule clusters from the metal surface as a sudden temperature decreases/increases like as noises in the detectors.
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Ingrid Jonak-Auer, ams AG, Technology R&D, Austria
Olesia Synooka, ams AG, Technology R&D, Austria
Andrea Kraxner, ams AG, Technology R&D, Austria
Frederic Roger, ams AG, Technology R&D, Austria
Abstract: With the ongoing miniaturization of CMOS technologies the need for integrated optical sensors on smaller scale CMOS nodes arises. In this paper we report on the development and implementation of different optical sensor concepts in high performance 0.18µm CMOS and HV-CMOS technologies on three different substrate materials. The integration process is such that complete modularity of the CMOS processes remains untouched and no additional masks or ion implantation steps are necessary for the sensor integration. The investigated processes support 1.8V and 3V standard CMOS functionality as well as HV transistors capable of operating voltages of 20V and 50V. These processes intrinsically offer a wide variety of junction combinations, which can be exploited for optical sensing purposes. The availability of junction depths from submicron to several microns enables the selection of spectral range from blue to infrared wavelengths. By appropriate layout the contributions of photo-generated carriers outside the target spectral range can be kept to a minimum. Furthermore by making use of other features intrinsically available in 0.18µm CMOS and HV-CMOS processes dark current rates of optoelectronic devices can be minimized. We present TCAD simulations as well as spectral responsivity, dark current and capacitance data measured for various photodiode layouts and the influence of different EPI and Bulk substrate materials thereon. We show examples of spectral responsivity of junction combinations optimized for peak sensitivity in the ranges of 400-500nm, 500-600nm and 700-900nm. Appropriate junction combination enables good spectral resolution for colour sensing applications even without any additional filter implementation. We also show that by appropriate use of shallow trenches dark current values of photodiodes can be reduced by at least a factor of 2 for bias voltages up to 4V
108
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