Green photoluminescence band in γ-irradiated oxygen-surplus silica glass

Previous studies have reported the existence of a green photoluminescence (PL) band in oxygen-deficient silica glass when exposed to ultraviolet (UV) light. Oxygen deficient defects (E-delta') were thought to be the origin of this PL band. In this article, we describe the characteristics of a green PL band in oxygen-surplus silica glass (excited by visible and UV light). At room temperature, we observed the full width at half maximum and lifetime of this PL band to be about 0.2 eV and 300 ns, which differed from the previously reported values of 0.4 eV and 20-30 ns, respectively. We propose that the peroxy radical (O-3=Si-O-O up arrow, up arrow: unpaired electron) or other oxygen surplus defects are the cause of this green PL band rather than oxygen deficient defects. (C) 1999 American Institute of Physics. [S0021-8979(99)03015-7].