Temperature programmed desorption (TPD) studies in ultra high vacuum revealed that diethyltellurium (DETe) and dimethylcadmium (DMCd) adsorb weakly on clean Si(100) and desorb upon heating without decomposing. These p...
Temperature programmed desorption (TPD) studies in ultra high vacuum revealed that diethyltellurium (DETe) and dimethylcadmium (DMCd) adsorb weakly on clean Si(100) and desorb upon heating without decomposing. These precursors adsorb both weakly and strongly on CdTe(111)A, with DMCd exhibiting the stronger interaction with the surface than DETe. Dimethylcadmium partially decomposes to produce Cd adatoms; a large fraction of the excess Cd atoms desorb upon heating. In contrast, DETe desorbs without decomposing, suggesting that the rate limiting step in CdTe MOCVD on CdTe(111)A is surface decomposition of the tellurium alkyl.
Changes in dynamic processes of relaxors due to a dc bias electric field have been studied in the reduced poly(vinylidene fluoride-trifluoroethylene), a copolymer system where relaxor-like behavior in the crystalline ...
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Changes in dynamic processes of relaxors due to a dc bias electric field have been studied in the reduced poly(vinylidene fluoride-trifluoroethylene), a copolymer system where relaxor-like behavior in the crystalline part can be separated from the glassy processes in the amorphous matrix. Strong electric field dependence of the Vogel-Fulcher temperature and the activation energy has been detected. Comparison of the results with those obtained in a classical inorganic relaxor, lanthanum-modified lead zirconate titanate ceramics, reveals that the nonlinear dielectric susceptibility dominantly influences the dielectric dynamics of relaxors in dc bias electric fields. We have additionally found that even low bias voltage effectively blocks the ac electrical conductivity of the studied copolymer.
Fundamental study was carried out for provision for acidification of soil due to acid rain. The influence of weight of the additive slag on elution behavior of the slag into water was studied in this study. Elution ex...
Fundamental study was carried out for provision for acidification of soil due to acid rain. The influence of weight of the additive slag on elution behavior of the slag into water was studied in this study. Elution experiment was carried out on a basis of JIS K 0058-1. Generally, the pH in the aqueous solution increased with an increase in weight of the additive slag. The pH converged to approximately eight. Calcium, magnesium and manganese, which were essential elements for plants, were eluted from the slag irrespective to elution condition. The eluted concentrations of Ca and Mg increased with an increase in weight of the additive slag. Silicon and zinc were also eluted depending on the conditions. Aluminum that was harmful for plants was not eluted from the used slag.
A major limitation of the current technology for GaN epitaxy is the availability of suitable substrates matched in both lattice constant and thermal expansion coefficient. One alternative for the development of GaN su...
A major limitation of the current technology for GaN epitaxy is the availability of suitable substrates matched in both lattice constant and thermal expansion coefficient. One alternative for the development of GaN substrates rests in the application of halide vapor phase epitaxy (HVPE) to produce GaN films at high growth rates. In this paper, we describe the growth of thick GaN films via the HVPE technique on (0001) sapphire and (111) Si substrates. At a temperature of 1030°C, films are grown at rates between 70 and 90 μm/hr, yielding total thicknesses exceeding 200 μm on sapphire. DCXRD measurements of GaN/sapphire indicate FWHM values less than 220 arcsec on 180 μm thick films. Room temperature PL measurements of GaN/sapphire indicate strong emission at 3.41 eV, with a FWHM value of 65 meV. Moreover, no detectable deep level emission was found in room temperature PL measurement. Under optimized conditions, films are morphologically smooth and optically clear. The GaN morphology appears to be a strong function of the initial nucleation conditions, which in turn are strongly affected by the partial pressure of GaCl. HVPE growth on (111) Si substrates is accomplished using an AlN MOVPE buffer layer.
In this article, nano-zinc oxide (ZnO) filled ethylene propylene diene monomer (EPDM) composites are prepared, and the mechanical (static and dynamic) properties and thermal conductivity are investigated respectively,...
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The N-doped hollow TiO2 nanoparticles were prepared by a simple method. The PS nanoparticles, ammonia and triethanolamine were used as templates, catalyst and inhibitor, respectively, the PS/TiO2 (core/shell) nanocomp...
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The N-doped hollow TiO2 nanoparticles were prepared by a simple method. The PS nanoparticles, ammonia and triethanolamine were used as templates, catalyst and inhibitor, respectively, the PS/TiO2 (core/shell) nanocomposite particles were synthesized by sol-gel process. The effect of the amounts of ammonia, triethanolamine and tetrabutyl titanate on surface morphology and thickness of TiO2 shell were investigated, respectively. The surface of TiO2 shell at ammonia amounts of 6.00g was rougher than that of TiO2 shell at ammonia amounts of 3.00g. The surface of TiO2 shell under triethanolamine amounts of 0.20g was smoother than that of TiO2 shell under ammonia amounts of 0.10g. The thicknesses of TiO2 shell were 25 and 43 nm when amounts of tetrabutyl titanate were 1.00 and 3.00 g, respectively. In this study, the triethanolamine was again used as N resource to prepare N-doped hollow TiO2 nanoparticles through cacination process of the PS/TiO2 nanocomposite particles, and it had visible light response.
CdTe/PEDOT-PSS microspheres were fabricated by seed polymerization. The morphology, structure, optical absorption and emission properties were characterized by using SEM, FT-IR, XPS, UV-Vis and fluorescent spectra. Th...
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CdTe/PEDOT-PSS microspheres were fabricated by seed polymerization. The morphology, structure, optical absorption and emission properties were characterized by using SEM, FT-IR, XPS, UV-Vis and fluorescent spectra. The results suggest that: the CdTe/PEDOT-PSS hybrids synthesized by seed polymerization exhibit uniform microsphere structure. The absorption spectrum for hybrids is the sum of the two components, and the peak at 550nm in emission spectrum is a result of charge transfer, which indicates the potential application of the microspheres optoelectronic and photovoltaic devices.
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