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

Valence-electron plasmons in an amorphous silicon-carbon alloy system a-SiₓC_1-x :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-SiₓC_1-x :H as a function of x is determined from the valence-electron density nᵥ obtained from observed plasmon energy ωₚ with use of ωₚ=[(4πe²m)nᵥ]1/2 and the results of thermal effusion experiments. The results are discussed in relation to the coordination of carbon atoms in a-SiₓC_1-x :H.