Photoinduced changes in the electronic structure of AS2Se3 glass

In situ irradiation experiments were performed on the oxygen-free surface of bulk As2Se3 glass that was fractured in the UHV environment of the X-ray photoelectron spectroscopy (XPS) chamber. The results are in agreement with theoretical simulations, which predict a large concentration of valence alternation pairs in this glass. Compared to previous experiments conducted in air, we find relatively small photoinduced changes in the XPS spectra. The analysis of high-resolution experimental data describes the nature of the light-induced permanent changes in the structural units of the Se atoms and reversible changes in the structural units of the As atoms. The valence band spectra do not appear affected significantly by laser irradiation. (C) 2003 Elsevier B.V. All rights reserved.