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Electrical Contacts (electrical + contact)
Selected AbstractsEffect of Grain Size Reduction and Geometrical Confinement in Fine Grained Copper: Potential Applications as a Material for Reversible Electrical Contacts,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Yannick Champion The potential of ultrafine grained copper as a material for reversible electrical contact is investigated. The influence of grain size and sample size on strength and electrical properties is discussed. The existence of an optimal grain size and the relevance of size effects for the mechanical properties are analyzed. [source] Semi-insulating (Cd,Mn)Te:V crystals: Electrical contactsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2007M. Witkowska-Baran Abstract The high-resistivity (Cd,Mn)Te is believed to be suitable to succesfully replace the commonly used (Cd,Zn)Te system as a material for manufacturing large-area X- and ,-ray detectors. The purpose of our study was to elaborate a method of preparing high quality (Cd,Mn)Te crystal plates as well as a technique of producing good electrical contacts to that material. (Cd,Mn)Te was grown using the Bridgman method. The crystals were doped with vanadium to the level of 1016 cm,3. The crystals are twinned in the (111) plane, but by slicing the crystal parallel to the twinning plane we obtained monocrystalline plates of large area (e.g. 30 × 30 mm2), which is essential for application purposes. Proper annealing of those plates in cadmium vapours allowed us to reduce the number of cadmium vacancies forming during the growth process. Due to the vanadium dopant acting as a compensating centre we obtained a semi-insulating material. In order to obtain good contacts to the (Cd,Mn)Te plates we used the method proposed initially for CdTe by Rioux et al. The ZnTe:Sb layers (,1 ,m thick) were grown on the epi-ready (Cd,Mn)Te:V plates by the MBE technique. The grown layers were p-type and formed a good electrical contact to the crystal plates. Finally , a standard technique was used to cover the ZnTe layer by a metal layer. The contacts formed on (111) surfaces of (Cd,Mn)Te were studied. We believe that the contacts to the (111) surface are important for applications. In the paper we describe techniques of preparing electrical contacts and results of their characterization. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Development of a Rapid Single-Drop Analysis Biosensor for Screening of Phenanthrene in Water SamplesELECTROANALYSIS, Issue 20 2004Abstract Detection techniques for biosensors often require bulky instruments or cells that are not feasible for in-field analysis. Our single-drop cell design, optimized in this work, comprised a screen-printed three-electrode (SPE), strip in horizontal position onto which a volume of 100,,L of sample or substrate solution was placed to ensure electrical contact (complete circuit). Together with optimized linear sweep voltammetry (LSV), parameters for the detection of the enzyme alkaline phosphatase (AP), the system was applied to a biosensor for the analysis of polycyclic aromatic hydrocarbons (PAHs), in environmental samples. A limit of detection (LOD), of 0.15,ppb was achieved for a model system with an IC50 value of 0.885 ppb and a linear range (LR), of 0.2,10,ppb. Application of the single drop analysis (SDA), format to a PAH biosensor gave a LOD of 1.4,ppb for detection of phenanthrene with an IC50 value of 29.3,ppb and linear range of 2,100,ppb. Proof of concept is shown with spiked sample analysis of phenanthrene in matrices such as sea, river and tap water. [source] Effect of Grain Size Reduction and Geometrical Confinement in Fine Grained Copper: Potential Applications as a Material for Reversible Electrical Contacts,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Yannick Champion The potential of ultrafine grained copper as a material for reversible electrical contact is investigated. The influence of grain size and sample size on strength and electrical properties is discussed. The existence of an optimal grain size and the relevance of size effects for the mechanical properties are analyzed. [source] Electrically Addressable Hybrid Architectures of Zinc Oxide Nanowires Grown on Aligned Carbon NanotubesADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Jong G. Ok Abstract The fabrication and characterization of hybrid architectures of ZnO nanowires (ZNWs) grown on organized carbon nanotubes (CNTs), by a two-step chemical vapor deposition (CVD) process involving CNT growth from a hydrocarbon source followed by ZNW growth using a Zn metal source, is reported. The ZNWs grow uniformly and radially from individual CNTs and CNT bundles, and the aligned morphology of the CNTs is not disturbed by the ZNW growth process. The nucleation and growth of ZnO crystals on CNTs are analyzed in relation to the classical vapor,solid mechanism. Importantly, the CNTs make uniform and distributed electrical contact to the ZNWs, with up to a 1000-fold yield advantage over conventional ZNW growth on a flat substrate. Hybrid ZNW/CNT sheets are fabricated by scalable CVD, rolling, and printing methods; and their electrical properties, which are governed by transport through the anisotropic CNT network, are characterized. Functional interaction between the ZNWs and CNTs is demonstrated by photoconductive behavior and photocurrent generation of the hybrid material under UV illumination. There is significant future opportunity to extend these processing methods to fabricate other functional oxides on CNTs, and to build devices that harness the attractive properties of ZNWs and CNTs with high volumetric efficiency over large areas. [source] Transparent carbon nanotube field emission devices for display and lampPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2007Yousuk Cho Abstract A new, simple method to fabricate transparent carbon nanotube field emission devices is developed. The highly graphitized, single wall carbon nanotubes (SWNTs) are attached to an Sn/ITO glass by the arc discharge method. Post-heat treatments of the sample below the deformation temperature of soda-lime glass form a Sn,SWNT composite, and the nanotubes form good mechanical adhesion and electrical contact with the substrates. When the composite is oxidized in air below 400 °C, the Sn particles change to a transparent oxide form. The emission current density of the heat-treated SWNT,Sn composite is about 1 mA/cm2 at an electric field of 3 V/,m. The emission current density of the SWNT,SnOx composite is similar. However, at a higher oxidation temperature, the emitter shows more stable emission property and longer life time. The transparency of the emitter can be useful in the design of emitter devices. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Semi-insulating (Cd,Mn)Te:V crystals: Electrical contactsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2007M. Witkowska-Baran Abstract The high-resistivity (Cd,Mn)Te is believed to be suitable to succesfully replace the commonly used (Cd,Zn)Te system as a material for manufacturing large-area X- and ,-ray detectors. The purpose of our study was to elaborate a method of preparing high quality (Cd,Mn)Te crystal plates as well as a technique of producing good electrical contacts to that material. (Cd,Mn)Te was grown using the Bridgman method. The crystals were doped with vanadium to the level of 1016 cm,3. The crystals are twinned in the (111) plane, but by slicing the crystal parallel to the twinning plane we obtained monocrystalline plates of large area (e.g. 30 × 30 mm2), which is essential for application purposes. Proper annealing of those plates in cadmium vapours allowed us to reduce the number of cadmium vacancies forming during the growth process. Due to the vanadium dopant acting as a compensating centre we obtained a semi-insulating material. In order to obtain good contacts to the (Cd,Mn)Te plates we used the method proposed initially for CdTe by Rioux et al. The ZnTe:Sb layers (,1 ,m thick) were grown on the epi-ready (Cd,Mn)Te:V plates by the MBE technique. The grown layers were p-type and formed a good electrical contact to the crystal plates. Finally , a standard technique was used to cover the ZnTe layer by a metal layer. The contacts formed on (111) surfaces of (Cd,Mn)Te were studied. We believe that the contacts to the (111) surface are important for applications. In the paper we describe techniques of preparing electrical contacts and results of their characterization. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] CdTe solar cell in a novel configurationPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 1 2004A. N. Tiwari Abstract Polycrystalline thin-film CdTe/CdS solar cells have been developed in a configuration in which a transparent conducting layer of indium tin oxide (ITO) has been used for the first time as a back electrical contact on p-CdTe. Solar cells of 7·9% efficiency were developed on SnOx:F-coated glass substrates with a low-temperature (<450°C) high-vacuum evaporation method. After the CdCl2 annealing treatment of the CdTe/CdS stack, a bromine methanol solution was used for etching the CdTe surface prior to the ITO deposition. The unique features of this solar cell with both front and back contacts being transparent and conducting are that the cell can be illuminated from either or both sides simultaneously like a ,bi-facial' cell, and it can be used in tandem solar cells. The solar cells with transparent conducting oxide back contact show long-term stable performance under accelerated test conditions. Copyright © 2004 John Wiley & Sons, Ltd. [source] Nanoscale Conducting Channels at the Surface of Organic Semiconductors Formed by Decoration of Molecular Steps with Self-Assembled MoleculesADVANCED FUNCTIONAL MATERIALS, Issue 23 2009Bumsu Lee Abstract Under certain conditions, self-assembling molecules preferentially bind to molecular steps at the surface of crystalline organic semiconductors, inducing a strong local doping effect. This creates macroscopically long conducting paths of nanoscale width (a single crystalline analogue of organic nanowires) that can span distances of up to 1,cm between electrical contacts. The observed effect of molecular step decoration opens intriguing possibilities for visualization, passivation, and selective doping of surface and interfacial defects in organic electronic devices and provides a novel system for research on nanoscale charge transport in organic semiconductors. In addition, this effect sheds light on the microscopic origin of nucleation and growth of self-assembled monolayers at organic surfaces. It can also have implications in electronic patterning, nanoscale chemical sensors, integrated interconnects and charge-transfer interfaces in organic transistors and solar cells. [source] Advanced silicon microstructures, sensors, and systemsIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2007Oliver Paul Non-Member Abstract This paper presents the progress in silicon-based biomedical microstructures, material characterization techniques, and mechanical microsystems by the authors' research team. Microneedle and microelectrode arrays with fluidic through-wafer vias and electrical contacts were developed. The structures are designed for dermatological and biological applications such as allergy testing, surface electromyography, and spatially resolved impedance spectroscopy. The characterization of thin films has relied on the bulge test. By the formulation of more powerful models, the application range of the bulge test was extended to elastically supported thin-film multilayers. This enables the mechanical properties of thin films to be determined reliably. Finally, progress in the operation and application of novel stress sensors based on CMOS diffusions and field effect transistors and exploiting the pseudo-Hall effect is reported. Their integration into powerful single-chip microsystems is described. Applications include stress mapping, force and torque measurements, and tactile surface probing of microcomponents. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Spatially Resolved Potential Distribution in Carbon Nanotube Cross-Junction DevicesADVANCED MATERIALS, Issue 25-26 2009Eduardo J. H. Lee Crossed-nanotube junctions, the basic constituents of carbon nanotube networks, are investigated by scanning photocurrent microscopy. The location of the predominant electrostatic potential drop, at the electrical contacts or at the junction, is found to be highly dependent on the transport regime. Also, whereas Schottky barriers are formed at M-S (metal,semiconductor) nanotube crossings, isotype heterojunctions are formed at S-S ones (figure). [source] Optical microscopy imaging method for detection of electromigration: Theory and experimentPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2007L. H. Li Abstract Electromigration is a microscopic phenomenon involving electric field-induced diffusion, which is very relevant to damage in interconnects. A common method to monitor interconnect degradation is through electrical resistance measurements, which requires direct electrical contacts. It is desirable to develop non-contact methods to monitor electromigration damage formation. Recently, we have proposed a novel Optical Microscopy Imaging Method (OMIM). Here we provide theoretical proof and additional experimental results. OMIM provides a new method for studying electromigration-induced damage. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Semi-insulating (Cd,Mn)Te:V crystals: Electrical contactsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2007M. Witkowska-Baran Abstract The high-resistivity (Cd,Mn)Te is believed to be suitable to succesfully replace the commonly used (Cd,Zn)Te system as a material for manufacturing large-area X- and ,-ray detectors. The purpose of our study was to elaborate a method of preparing high quality (Cd,Mn)Te crystal plates as well as a technique of producing good electrical contacts to that material. (Cd,Mn)Te was grown using the Bridgman method. The crystals were doped with vanadium to the level of 1016 cm,3. The crystals are twinned in the (111) plane, but by slicing the crystal parallel to the twinning plane we obtained monocrystalline plates of large area (e.g. 30 × 30 mm2), which is essential for application purposes. Proper annealing of those plates in cadmium vapours allowed us to reduce the number of cadmium vacancies forming during the growth process. Due to the vanadium dopant acting as a compensating centre we obtained a semi-insulating material. In order to obtain good contacts to the (Cd,Mn)Te plates we used the method proposed initially for CdTe by Rioux et al. The ZnTe:Sb layers (,1 ,m thick) were grown on the epi-ready (Cd,Mn)Te:V plates by the MBE technique. The grown layers were p-type and formed a good electrical contact to the crystal plates. Finally , a standard technique was used to cover the ZnTe layer by a metal layer. The contacts formed on (111) surfaces of (Cd,Mn)Te were studied. We believe that the contacts to the (111) surface are important for applications. In the paper we describe techniques of preparing electrical contacts and results of their characterization. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] IR spectroscopy of adsorbates on ultrathin metal filmsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 13 2005Annemarie Pucci Abstract Metal films with thickness in the nanometer range are optically transparent. With IR transmittance spectroscopy the in-plane film conductivity with its correlation to the film-growth process can be studied without electrical contacts and, on metal-island films, adsorbate vibrations can be observed because of surface enhanced IR absorption (SEIRA). Their analysis enables insight into the adsorbate-metal bonding and therefore gives information on the available adsorption sites and the crystalline facets correlated to. As in IR reflection absorption spectra dipole,dipole interaction of molecules on different sites modifies the vibration lines according to the degree of disorder ("atomic roughness"). Depending on that roughness IR spectra of adsorbate vibrations may be further modified because of their interaction with electronic excitations of the film. So, the limited facet size on cold-condensed metal films leads to additional IR activity: Raman lines of certain centrosymmetric adsorbate molecules (C2H4) are observed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Development of thin-film Cu(In,Ga)Se2 and CdTe solar cellsPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 2-3 2004A. Romeo Abstract Cu(In,Ga)Se2 and CdTe heterojunction solar cells grown on rigid (glass) or flexible foil substrates require p -type absorber layers of optimum optoelectronic properties and n -type wide-bandgap partner layers to form the p,n junction. Transparent conducting oxide and specific metal layers are used for front and back electrical contacts. Efficiencies of solar cells depend on various deposition methods as they control the optoelectronic properties of the layers and interfaces. Certain treatments, such as addition of Na in Cu(In,Ga)Se2 and CdCl2 treatment of CdTe have a direct influence on the electronic properties of the absorber layers and efficiency of solar cells. Processes for the development of superstrate and substrate solar cells are reviewed. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||||||||