Behavior of Plasmons in an Amorphous Silicon-Carbon Alloy System Studied by X-Ray Photoelectron Spectroscopy

Abstract

Valence-electron plasmons in an amorphous silicon-carbon alloy system $a\ensuremath{-}{\mathrm{Si}}_{x}{\mathrm{C}}_{1\ensuremath{-}x} :\mathrm{H}$ ($0<~x<~1.0$) are observed as the satellites of core-electron levels in the x-ray photoemission spectra. The atomic density of $a\ensuremath{-}{\mathrm{Si}}_{x}{\mathrm{C}}_{1\ensuremath{-}x} :\mathrm{H}$ as a function of $x$ is determined from the valence-electron density ${n}_{v}$ obtained from observed plasmon energy $\ensuremath{\hbar}{\ensuremath{\omega}}_{p}$ with use of $\ensuremath{\hbar}{\ensuremath{\omega}}_{p}=\ensuremath{\hbar}{[(\frac{4\ensuremath{\pi}{e}^{2}}{m}){n}_{v}]}^{\frac{1}{2}}$ and the results of thermal effusion experiments. The results are discussed in relation to the coordination of carbon atoms in $a\ensuremath{-}{\mathrm{Si}}_{x}{\mathrm{C}}_{1\ensuremath{-}x} :\mathrm{H}$.