Photobleaching of sol-gel-derived germanium oxide glass thin films

Abstract

Photobleaching of the optical absorption band in the 5-eV region of sol-gel-derived germanium oxide glass thin films was examined with the irradiation of the 5-eV light. The photobleaching represented by the saturated absorption coefficient change (-Delta alpha) and the ratio of the neutral oxygen monovacancies to neutral oxygen divacancies concentrations for the germanium oxide were 175 cm(-1) and 0.113, respectively. These values are larger than those of the pure germanium oxide bulk glass as well as germanosilicate thin films. The changes in bonding configuration around Ge atom by ultraviolet illumination were analyzed using x-ray photoelectron spectroscopy.