Search

We present the results of extensive modeling of hydrogenated amorphous silicon (a-Si:H) by combined ab initio molecular dynamics, an improved signal processing technique, and computer visualization, focusing on vibrational properties of a-Si:H. By comparing the theoretical and experimental vibrational spectra we correlate the hydrogen and silicon dynamics with the structural stability, bonding geometry, and diffusion in the a-Si:H material. Microscopic characteristics that cannot be obtained by other techniques, namely, hydrogen migration, bond switching, and silicon dangling bond passivation, are extracted from the atomic dynamics. We also demonstrate that this method offers the possibility of accessing other important macroscopic characteristics of a-Si:H and its stability in general. The approach we have developed can be used as well to model all aspects of a-Si:H dynamics, including the detrimental Staebler–Wronski effect. [ABSTRACT FROM AUTHOR]

Describes a procedure for the derivation of the differential capacitance of the hydrogenated amorphous silicon Schottky barrier (SB) from surface photovoltage measurements. Result of the illumination of amorphous silicon SB with light of appropriate wavelength; Explanation for the variation in junction capacitance in amorphous silicon; Details of experimental techniques used.

Presents information on a study which investigated the properties of the amorphous silicon schottky barrier by surface photovoltage spectroscopy. Methodology of the study; Results and discussion.

Presents a study which examined the ultrasonic attenuation in a dilute chromium alloy by the spin-density wave. Strong peak in the attenuation seen in chromium; Behavior of the attenuation at the spin-flip temperature.

The de Haas-van Alphen (dHvA) effect in the antiferromagnetic compound FeGe2 is studied experimentally. A sharp suppression of the amplitude of the first harmonic of the dHvA oscillations is observed for a number of orbits on the Fermi surface of FeGe2. The change in the conditions for suppression of the amplitude ("spin zeroes") when FeGe2 is doped with cobalt is determined. A method for analyzing the experimental data is proposed in which the g-factors of the conduction electrons are computed on the basis of calculations of the spin-polarized electron structure of the band antiferromagnet taking spin-orbital interactions into account. The exchange enhancement factor for spin paramagnetism in FeGe2 is also calculated. [ABSTRACT FROM AUTHOR]