On the light absorption in amorphous semiconductors

Recent measurements of optical absorption in doped amorphous semiconductors (a-Si: H and a-Ge : H) have revealed that long-range potential fluctuations play a decisive role in the absorption mechanism. The theory of such effects was initially developed for crystalline semiconductors, and it is usually not applied in the appropriate form for the interpretation of experimental data in amorphous materials. We use this theory in the analysis of optical-absorption data for amorphous semiconductors, and show its quantitative agreement with experimental results. (C) 2003 Kluwer Academic Publishers.