Phosphorescence and Thermoluminescence of UV-Irradiated SrO Powders at Temperatures from 120 K to 350 K

Long-lived phosphorescence and thermoluminescence (TL) from UV-irradiated SrO powders under high vacuum are observed at low temperature. Phosphorescence decays following a t -1 law below 160 K in the time range 10-103 s. The emission spectra of phosphorescence and TL have a peak at 2.7 eV. The luminescence is quenched by O2 gas exposure at low temperatures. On the basis of the phosphorescence decay and TL glow curves, plausible emission mechanisms are discussed in terms of a thermally assisted tunneling recombination model between distant electron and hole traps and a first-order decay model with an energy distribution of trap depth. The observations are well described by the recombination model.