Electronic structures of Ag(Cu)–As–Se glasses

Abstract

Fundamental physical properties of Ag(Cu)–As–Se glasses along Ag(Cu)–As 2Se 3 tie lines have been investigated in order to obtain knowledge of electronic structures. Optically, Ag and Cu addition to As 2Se 3 induce red shifts of the absorption edges, in which the shift in the Ag–As–Se system is smaller than that in the Cu–As–Se system. In X-ray photoelectron spectra, Ag 4d and Cu 3d states gradually appear at an upper valence band with increasing Ag(Cu) content. Further, a transient photocurrent study shows that the localized states N t ( E) at E≃0.5 eV from the valence band are distributed exponentially, N t ( E)∝exp(− E/ kT 0), in Ag(Cu)–As–Se glasses, in which the Ag–As–Se system possesses a greater characteristic temperature T 0. On the bases of these observations, electronic structures of Ag(Cu)–As–Se glasses are considered from a unified point-of-view.