Time-dependent photoluminescence fatigue-recovery phenomena in germanium sulfide glasses

Photoluminescence (PL) fatigue-recovery phenomena in germanium sulfide were investigated, and the temperature dependence of the time-dependent PL intensity for several compositions (Ge33.3S66.7, Ge20S80 and Ge10S90) was analyzed. Side-bands were observed and two bands out of them for argon-ion laser excitation, one at 2.25 eV for all compositions and the other extended from 2.15 to 2.45 for Ge10S90 especially at the lower temperatures, were used to fully describe the time-dependence.The functional form which is similar to those in the previous report [T. Nakanishi et al., J. Non-Cryst. Solids 354 (2008) 1627] was used and it is extended to account for the effect of side-band at below 30 K for Ge20S80 and monotonous decrease of background for Ge10S90.