Results 1 - 10 of 13742
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[en] We report on the characterization of mercury cadmium telluride (Hg1-xCdxTe) film grown by the isothermal vapor phase epitaxial method (ISOVPE) and on the surface conversion of bulk Hg1-xCdxTe to larger bandgap material. The crystal perfection is evaluated using defect etching, electron beam and electrolyte electroreflectance (EBER and EER), and Rutherford backscattering spectrometry (RBS). Hall measurements are used to measure carrier densities and mobilities. Surface concentrations and concentration profiles are measured for the ISOVPE grown layers by transmission Fourier transform infrared spectroscopy (FTIR) and electron-probe microanalysis (EPMA) to establish quantitative informations about composition control. Metal--insulator-semiconductor (MIS) structures were made and the properties important to device performance such as compositional uniformity, storage time, and carrier concentration are measured. The ISOVPE layers are compared in quality to films grown by other methods and show promise for MIS devices
[en] Tunneling measurements were made on thin films (700--1400 A) of GeTe to determine the dependence of the superconducting energy gap on carrier concentration. Temperatures as low as approx.25 mK were used and perpendicular magnetic fields were applied to measure the critical fields. The energy gap Δ was found to vary from 30 to 42 μeV for carrier concentrations from 1.5 to 2.4 x 1021/cm3
[en] It is shown that transformation of photoelectric characteristics of sensors based on Cd1−xZnxTe (x = 0.05–0.15) crystals into parametric spectral I(λ)-dI/dλ, kinetic I(t)-dI/dt, and dynamic U-I(Δy)f,λ signatures (I(λ) is the photocurrent, U is the voltage, f is the frequency, t is the time, and y is the coordinate) makes it possible to reveal integrative photoresponse features caused by the photoresponse asymmetry and nonlinearity. Indices of asymmetry and balance of dynamic and energy photoinduced states are suggested; these indices represent systematically the effect of multiscale fields on photoelectronic processes. Using these indices, the ranges of external effects at which systematic features of photoresponse of sensors are minimal or maximal are determined, which makes it possible to increase the efficiency of purposeful selection and treatment of sensors.
[en] A new method of crystallization of cadmium telluride is described. The growth is carried out, by normal freezing of a tellurium-rich solution, in a vertical Bridgman furnace. Crystals of high purity (45mm in diameter-150mm in length) are obtained with this process
[en] Diantimony-tellurium, Sb2Te, Mr=371.1, trigonal, Panti 3m1, a=4.272 (1), c=17.633 (3) A, V=278.6 (2) A3, Z=3 Dx=6.63 Mg m-3, λ(MoK anti α)=0.7107 A, μ=22.11 mm-1, F(000)=462, T=294 K, final R=0.035 for 245 independent observed reflections. The structure of Sb2Te consists of nine layers stacked along the c axis and presents the combination of five-layer stacks of Sb2Te3 and two-layer stacks of Sb2. (orig.)
[en] Bismuth tellurite is a photorefractive material for holographic data storage offering unique fixing capabilities. Important material and electro-optic properties obtained by four-wave-mixing and data storage experiments are reviewed and recent results concerning the applicability of bismuth tellurite for holographic data storage, including dynamic range, multiplexing capabilities and bit-error evaluations, are presented. Furthermore, it is demonstrated how the latest progress in growing Bi2TeO5 made this crystal a candidate for durable holographic recording media.
[en] According to the energy band model for the Al-CdTe-Ag sandwich structure, we have investigate to the mechanism of the current limited transport(CLT). As the bias voltage applied to the Alsup(+) and Agsup(+) electrode, the potential barrier difference for this structure was found 0.2eV. From what this results, we conclude that the mechanism of the current limited transport due to the potential barrier of the contact limited current. Not only this phenomena but also the annealing effect of thin film was shown that the distingushable for virgin film. (Author)