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Electrical Characterization (electrical + characterization)
Selected AbstractsThiophene,Benzothiadiazole Co-Oligomers: Synthesis, Optoelectronic Properties, Electrical Characterization, and Thin-Film PatterningADVANCED FUNCTIONAL MATERIALS, Issue 3 2010Manuela Melucci Abstract Newly synthesized thiophene (T) and benzothiadiazole (B) co-oligomers of different size, alternation motifs, and alkyl substitution types are reported. Combined spectroscopic data, electrochemical analysis, and theoretical calculations show that the insertion of a single electron-deficient B unit into the aromatic backbone strongly affects the LUMO energy level. The insertion of additional B units has only a minor effect on the electronic properties. Cast films of oligomers with two alternated B rings (B,T,B inner core) display crystalline order. Bottom-contact FETs based on films cast on bare SiO2 show hole-charge mobilities of 1,×,10,3,5,×,10,3,cm2 V,1s,1 and Ion/Ioff ratios of 105,106. Solution-cast films of cyclohexyl-substituted compounds are amorphous and do not show FET behavior. However, the lack of order observed in these films can be overcome by nanorubbing and unconventional wet lithography, which allow for fine control of structural order in thin deposits. [source] Ni,YSZ Solid Oxide Fuel Cell Anode Behavior Upon Redox Cycling Based on Electrical CharacterizationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2007Trine Klemensø Nickel (Ni),yttria-stabilized zirconia (YSZ) cermets are a prevalent material used for solid oxide fuel cells. The cermet degrades upon redox cycling. The degradation is related to microstructural changes, but knowledge of the mechanisms has been limited. Direct current conductivity measurements were performed on cermets and cermets where the Ni component was removed. Measurements were carried out before, during, and after redox cycling the cermet. The cermet conductivity degraded over time due to sintering of the nickel phase. Following oxidizing events, the conductivity of the cermets improved, whereas the conductivity of the YSZ phase decreased. An improved model of the redox degradation mechanism was established based on the measurements. [source] ChemInform Abstract: Structural and Electrical Characterization of the Novel SrCo0.9Sb0.1O3-, Perovskite: Evaluation as a Solid Oxide Fuel Cell Cathode Material.CHEMINFORM, Issue 10 2008A. Aguadero Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Magnetic and Electrical Characterizations of Half-Metallic Fe3O4 Nanowires,ADVANCED MATERIALS, Issue 17 2007M.-T. Chang The magnetic properties of magnetite (Fe3O4) nanowires are investigated by means of electron holography, which deduces the magnetic information from the phase shift of electrons. The magnetic flux is parallel to the longitudinal axis of the nanowires (see figure). Observations on the magnetization distribution reveal the possibility of regulating the spin current with the half-metallic nanowires, owing to the controlled magnetization distribution in the 1D form. [source] Physical Modeling and Electrodynamic Characterization of Dielectric Slurries by Impedance Spectroscopy (Part II)JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2008Vladimir Petrovsky Electrical characterization of dielectric slurries, as 0,3 composite systems, can provide valuable information on the dielectric properties of suspended particles. A new approach developed in our laboratory is based on impedance spectroscopy measurements of the slurries containing dispersed dielectric powders. Dielectric constants of the particles are determined through analysis of the low-frequency section of the impedance spectra. It was shown previously that this approach allows accurate and reliable measurement of dielectric constant of particles (,: ,100,2000) using host liquids (,: ,10,65). This study addresses the validation of this new method with physical model experiments using millimeter-sized sintered BaTiO3 model samples suspended in the liquid. Impedance spectra of barium titanate powder slurries were compared with the spectra of the model samples containing macroscopic cubes prepared by sintering of the same starting powder. This comparison shows a good agreement between the impedance spectra of powder and bulk BaTiO3 and validates the reliability of the new method to determine the dielectric constant of particulate materials. [source] Self-Assembly of DNA-Templated Polypyrrole Nanowires: Spontaneous Formation of Conductive Nanoropes,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2008Stela Pruneanu Abstract Polypyrrole nanowires formed by polymerization of pyrrole on a DNA template self-assemble into rope-like structures. These ,nanoropes' may be quite smooth (diameters 5,30,nm) or may show frayed ends where individual strands are visible. A combination of electric force microscopy, conductive atomic force microscopy and two-terminal current,voltage measurements show that they are conductive. Nanoropes adhere more weakly to hydrophobic surfaces prepared by silanization of SiO2 than to the clean oxide; this effect can be used to aid the combing of the nanoropes across microelectrode devices for electrical characterization. [source] Disordered lattice networks: general theory and simulationsINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 6 2005Stefano GiordanoArticle first published online: 16 NOV 200 Abstract In this work we develop a theory for describing random networks of resistors of the most general topology. This approach generalizes and unifies several statistical theories available in literature. We consider an n-dimensional anisotropic random lattice where each node of the network is connected to a reference node through a given random resistor. This topology includes many structures of great interest both for theoretical and practical applications. For example, the one-dimensional systems correspond to random ladder networks, two-dimensional structures model films deposited on substrates and three-dimensional lattices describe random heterogeneous materials. Moreover, the theory is able to take into account the anisotropic percolation problem for two- and three-dimensional structures. The analytical results allow us to obtain the average behaviour of such networks, i.e. the electrical characterization of the corresponding physical systems. This effective medium theory is developed starting from the properties of the lattice Green's function of the network and from an ad hoc mean field procedure. An accurate analytical study of the related lattice Green's functions has been conducted obtaining many closed form results expressed in terms of elliptic integrals. All the theoretical results have been verified by means of numerical Monte-Carlo simulations obtaining a remarkably good agreement between numerical and theoretical values. Copyright © 2005 John Wiley & Sons, Ltd. [source] Using finite element method to calculate capacitance, inductance, characteristic impedance of open microstrip linesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2008Sarhan M. Musa Abstract Microstrip transmission lines have received more interest and attention in microwave integrated circuit design. Analysis and electrical characterization of single and coupled microstrip lines have been a major focus for researchers in integrated circuit technology. In this article, we will illustrate modeling of the capacitance, inductance, and characteristic impedance of quasi-TEM for open microstrip lines using finite element method with COMSOL multiphysics package. In this work, we determine the capacitance per unit length, inductance per unit length, and characteristic impedance of open microstrip lines (single-strip, double strip, and three-strip). We compare our results with those obtained by other methods and found them to be in agreement. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 611,614, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23164 [source] Growth and characterization of Sn doped ZnO thin films by pulsed laser depositionPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2006E. López-Ponce Abstract Sn:ZnO thin films with different Sn concentrations were grown by pulsed laser deposition (PLD) onto single-crystal Si(001) substrates at an oxygen pressure of 2 × 10,2 mbar and substrate temperature of 600 °C. The targets used were high density Sn:ZnO pellets with different Sn concentrations produced by mixing ZnO and SnO2 by conventional ceramic routes. A deep structural and electrical characterization was carried out in order to determine the role of an increasing Sn nominal concentration on the ZnO film transport properties. Only films with a nominal 0.1 at% Sn show an improvement of the transport properties, lower resistivity and higher donor concentration, with respect to pure ZnO thin films. For films with larger Sn nominal concentrations segregated SnZnO phases appear that lead to larger film resistivities and no increase in donor concentration. The 0.1 at% Sn film is accordingly a good candidate to study the possible room temperature ferromagnetism when co doping with Mn. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preparation and electrical characterization of amorphous BaO, SrO and Ba0.7Sr0.3O as high-k gate dielectricsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2010D. Müller-Sajak Abstract We report on the measurement of band offsets and electrical characterizations of amorphous BaO, SrO and Ba0.7Sr0.3O as alternative gate oxides grown on n-Si(001) at room temperature without further treatments. These materials provide relative dielectric constants close to those expected from bulk values even for ultra-thin films (equivalent oxide thicknesses below 1 nm) and posess very low rechargeable trap densities. Interface defect densities are comparable to other high-k materials for BaO and SrO films, but an order of magnitude lower for Ba0.7Sr0.3O. This demonstrates the importance of both chemical and structural interface effects (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Defect profiles in semiconductor structuresPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2007P. G. Coleman Abstract Variable-energy positron annihilation spectroscopy (VEPAS) has found applications in structural and electronic analysis of thin films and near-surface layers, nanoporous materials, ion implantation, silicon photonics, and vacancy engineering. In all this applied work it is essential that VEPAS is treated as a normal member of the arsenal of spectroscopies available to the semiconductor research community. Examples are presented of how useful insights into current problems in semiconductor physics and technology have been gained by combinations of VEPAS and other techniques such as secondary ion mass spectrometry, transmission electron microscopy, electrical characterization, and optical techniques such as photoluminescence and optically-detected magnetic resonance. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Structural and electrical characterization of a -plane GaN grown on a -plane SiCPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2003M. D. Craven Abstract Planar nonpolar () a -plane GaN thin films were grown on () a -plane 6H-SiC substrates via metalorganic chemical vapor deposition by depositing a high temperature AlN buffer layer prior to the epitaxial GaN growth. The orientation of the GaN film and AlN buffer layer directly match that of the SiC substrate, as determined by on- and off-axis X-ray diffraction measurements. The morphological evolution of GaN grown on the AlN buffer layers was investigated using atomic force microscopy. Microstructural characterization of the coalesced a -plane GaN films provided by plan-view transmission electron microscopy revealed threading dislocation and stacking fault densities of ,3 × 1010 cm,2 and ,7 × 105 cm,1, respectively. Structural comparisons to a -plane GaN films grown on r -plane sapphire substrates are presented. Si-doped films were grown with a variety of Si/Ga ratios and electrically characterized using Hall effect measurements. A maximum Hall mobility of 109 cm2/Vs was attained at a carrier concentration of 1.8 × 1019 cm,3. [source] Encapsulating Eu3+ complex doped layers to improve Si-based solar cell efficiencyPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 8 2009Alessia Le Donne Abstract This paper reports the electrical characterization of commercially available crystalline silicon solar cells encapsulated with poly-vinylacetate doped with different Eu3+ organic complexes. The inclusion of these complexes in the encapsulating matrix allows down-shifting of the solar spectrum components below 420,nm toward the maximum quantum efficiency of the solar cells. This effect has been proven under Air Mass 1·5 conditions (simulating terrestrial applications) where an increase of the total power delivered by the encapsulated cells has been observed. Moreover, this enhancement has been obtained using very low percentage by weight of organolanthanide dopants, allowing a reduction in the Watt peak price. At higher concentrations a strong quenching of the energy transfer from the organic antenna to the lanthanide ion has been observed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Optical and electrical properties of laser texturing for high-efficiency solar cellsPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 3 2006Malcolm Abbott Abstract A process using laser-ablated pits to texture the front surface of monocrystalline and multicrystalline silicon solar cells is described. Optical and electrical characterization demonstrates that the technique performs as well as upright random pyramid texturing and causes no laser-induced defects or laser shunting. Double-sided buried contact solar cells fabricated with laser texture performed as well as those fabricated with upright random pyramid textures on 1,,,cm, p type float-zoned wafers. Copyright © 2006 John Wiley & Sons, Ltd. [source] Electrical transport properties of aliovalent cation-doped CeO2ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2009Mark C. Pearce Abstract We report the comparative electrical properties of monovalent (Na+), divalent (Ca2+, Sr2+), trivalent (In3+, La3+) and coupled substitution of divalent and trivalent (Ca2+ + Sm3+) cation-doped CeO2. The investigated samples were prepared by solid-state reaction (ceramic) using the corresponding metal oxides and salts in the temperature range 1000,1600 °C in air. Powder X-ray diffraction (PXRD), laser particle size analysis (LPSA), scanning electron microscopy (SEM), and ac impedance spectroscopy measurements were employed for structural, morphology, and electrical characterization. PXRD studies reveal the formation of single-phase cubic fluorite-type structures for all investigated samples except those doped with In3+. The variation of lattice parameters is consistent with ionic radii (IR) of the dopant metal ions, with the exception of Na+ -doped CeO2. Our attempt to substitute In3+ for Ce4+ in CeO2 using both ceramic and wet chemical methods was unsuccessful. Furthermore, diffraction peaks attributed to CeO2 and In2O3 were observed up to sintering conditions of 1600 °C. Among the single-phase compounds investigated, Ce0.85Ca0.05Sm0.1O1.9 exhibits the highest bulk conductivity of 1.3 × 10,3 S/cm at 500 °C with activation energy of 0.64 eV in air. The electrical conductivity data obtained for Ce0.85Ca0.05Sm0.1O1.9 in air and Ar were found to be very similar over the investigated temperature range, indicating the absence of p-electronic conduction in the high oxygen partial pressure (pO2) range which is consistent with literature reported on Sm-doped CeO2. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Growth and characterization of gallium oxide thin films by radiofrequency magnetron sputteringPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2008P. Marie Abstract Undoped and Neodymium-doped gallium oxide (Ga2O3) thin films of about 500 nm thickness were successfully grown at different temperatures ranging from 100 up to 600 °C by radiofrequency magnetron sputtering. Post-annealing treatments were carried out at 900 °C and 1000 °C. The obtained films were (400) textured and a grain size of a few tens of nanometres was found. Optical and electrical characterizations led to a figure of merit of about 1.9 × 10,4. These films were successfully doped with Neodymium by a co-sputtering method. The photoluminescence experiments for the Nd-doped ,-Ga2O3 films clearly showed the rare-earth emitting signature. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Role of interfaces on the direct tunneling and the inelastic tunneling behaviors through metal/alkylsilane/silicon junctionsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2006D. K. Aswal Abstract We studied the influence of the end group of the alkylsilane molecule used in Self Assembled Monolayer (SAM) in Silicon/SAM/Metal junctions. By Inelastic Electron Tunneling spectroscopy (IETS), we showed the formation of a covalent bond between the molecules and the gold electrode in the case of a thiol terminated alkylsilane. By electrical characterizations, we demonstrated that the thiol group at the interface avoids diffusion of gold into the molecule even for a 3 carbons chain. For this short molecule, we observed pure tunnel conduction with barrier height at the monolayer/Si and monolayer/Au interfaces found to be respectively 2.14 and 2.56 eV. These values were obtained using Simmons equation with an effective mass parameter m * = 0.16me (me = mass of the electron). This extends the demonstration of the excellent tunnel dielectric behavior of these organic monolayers down to 3 carbon atoms with a thiol/Au bond at the interface. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preparation and electrical characterization of amorphous BaO, SrO and Ba0.7Sr0.3O as high-k gate dielectricsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2010D. Müller-Sajak Abstract We report on the measurement of band offsets and electrical characterizations of amorphous BaO, SrO and Ba0.7Sr0.3O as alternative gate oxides grown on n-Si(001) at room temperature without further treatments. These materials provide relative dielectric constants close to those expected from bulk values even for ultra-thin films (equivalent oxide thicknesses below 1 nm) and posess very low rechargeable trap densities. Interface defect densities are comparable to other high-k materials for BaO and SrO films, but an order of magnitude lower for Ba0.7Sr0.3O. This demonstrates the importance of both chemical and structural interface effects (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Structural, optical, and electrical characterizations of epitaxial lifted-off InGaAs/InAlAs metamorphic heterostructures bonded on AlN ceramic substratesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2008Y. Jeong Abstract We investigated epitaxial lift-off (ELO) of In0.57Ga0.43As/In0.56Al0.44As metamorphic high electron mobility heterostructures and their van der Waals bonding (VWB) on AlN ceramic substrates. Structural, optical, and electrical characterizations were carried out for samples obtained by ELO and VWB, in comparison with on-wafer counterparts before ELO. We confirmed a strain release after ELO and VWB from xray diffraction, and observed a consequent photoluminescence energy shift. The ELO samples exhibit very high electron mobilities owing to the high indium contents and successful ELO and VWB processes. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||||||||