ELECTRONIC-STRUCTURE OF AMORPHOUS-SEMICONDUCTORS STUDIED BY BOTH X-RAY PHOTOELECTRON AND SOFT-X-RAY SPECTROSCOPIES

Complementary information on the valence and conduction states of soli ds can be obtained by using both soft X-ray (SXS) and X-ray photoelect ron (XPS) spectroscopies. From X-ray emission (and absorption) spectra , it is possible to probe local and symmetry-selected valence (and con duction) band states by studying electronic transitions involving a co re level and the outer occupied (or unoccupied) electronic states. The results can thus be compared to the XPS valence band spectra which pr ovide the total VB distribution modulated by photoionisation cross-sec tions. Moreover, the information is quite complementary to that deduce d from the optical spectra. The possibilities of these methods are dis cussed and results obtained for amorphous semiconductors are presented .