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Material Exhibits (material + exhibit)

Distribution by Scientific Domains
Polymers and Materials Science50%
Physics and Astronomy50%

Selected Abstracts

Defects and structure of µc-SiOx:H deposited by PECVD

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010
Lihong Xiao
Abstract Electronic transport and paramagnetic defects detected by Electron Spin Resonance (ESR) in both intrinsic and -type silicon oxide prepared by PECVD were investigated. The structure and alloy composition of the material were varied all the way from microcrystalline silicon (µc-Si:H) to amorphous silicon oxide (a-SiOX:H). The transition-phase-mixture material is called "microcrystalline silicon oxide" (µc-SiOX:H). In undoped samples we find a strong reduction of the dark conductivity from 10 -3to 10 -12 S/cm and an increase of the spin density from1017 to 3×1019 cm -3 as the crystallinity decreases from 80% to 0%. The variation of the dark conductivity in phosphorous doped samples was even higher from 101 to 10 -12 S/cm. ESR spectra of intrinsic material consist of a single featureless line with g-values in the range of 2.0043,2.005 depending on the structure and alloying. The spectra of -type material exhibit a broader range of g-values of 1.998,2.0043 due to strong variations of the Fermi level over the entire crystallinity range. The results are discussed within the frame of current understanding of µc-SiOX:H as a phase mixture of µc-Si:H crystallites embedded in a-SiOX:H matrix (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Studies on the structural, thermal and optical behaviour of solution grown organic NLO material: 8-hydroxyquinoline

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2007
N. Vijayan
Abstract Single crystal of 8-hydroxyquinoline (8HQ) having chemical formula C9H7NO, an organic nonlinear optical (NLO) material has been successfully grown by slow evaporation solution growth technique at room temperature. The crystal system has been confirmed from the powder X-ray diffraction (PXRD) analysis. The crystalline perfection was evaluated by high resolution X-ray diffractometry (HRXRD). From this analysis we found that the quality of the crystal is quite good. However, a very low angle (tilt angle 14 arc sec) boundary was observed which might be due to entrapping of solvent molecules in the crystal during growth. Its optical behavior has been examined by UV-Vis. analysis, which shows the absence of absorbance between the wavelengths ranging from 400 to 1200 nm. From the thermal analysis it was observed that the material exhibits single sharp weight loss starting at 113°C without any degradation. The laser damage threshold was measured at single shot mode and the SHG behavior has been tested using Nd:YAG laser as a source. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Enhancement of Piezoelectric Response in Scandium Aluminum Nitride Alloy Thin Films Prepared by Dual Reactive Cosputtering

ADVANCED MATERIALS, Issue 5 2009
Morito Akiyama
A high-temperature piezoelectric material exhibits a good balance between high maximum use temperature and large piezoelectricity. This is achieved by the combination of the discovery of a phase transition in scandium aluminum nitride (ScxAl1,,,xN) alloy thin films, and the use of dual cosputtering, which leads to nonequilibrium alloy thin films. [source]

A Silicon Carbonitride Ceramic with Anomalously High Piezoresistivity

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2008
Ligong Zhang
The piezoresistive behavior of a silicon carbonitride ceramic derived from a polymer precursor is investigated under a uniaxial compressive loading condition. The electric conductivity has been measured as a function of the applied stress along both longitudinal and transverse directions. The gauge factor of the materials was then calculated from the data at different stress levels. The results show that the material exhibits an extremely high piezoresistive coefficient along both directions, ranging from 1000 to 4000, which are much higher than any existing ceramic material. The results also reveal that the gauge factor decreases significantly with increasing applied stress. A theoretical model based on the tunneling,percolation mechanism has been developed to explain the stress dependence of the gauge factor. The unique piezoresistive behavior is attributed to the unique self-assembled nanodomain structure of the material. [source]