Recombination processes in the Y3Al5O12:Ce3+ scintillator

The roentgenoluminescence spectra, temperature-dependent activator luminescence, optically stimulated luminescence, and the effect of IR irradiation on the yield and spectral composition of the low-temperature roentgenoluminescence and thermoluminescence curves of the Y3Al5O12:Ce3+ scintillator have been studied in the temperature range 85-295 K. The results, coupled with earlier data, suggest that the Ce3+ ions in the garnet crystal studied form Ce(3+)p hole centers and increase the concentration of electronic F--centers responsible for the IR stimulation band at 940 nm. The reduction in roentgenoluminescence yield on cooling Y3Al5O12:Ce3+ to below 230 K is due to the significant localization of excited carriers at defects, which show up in thermoluminescence peaks and optical stimulation spectra. The low-temperature Ce3+ luminescence in Y3Al5O12:Ce3+ seems to result from the recombination of activator-bound excitons.