KINETICS OF LUMINESCENCE DECAY IN ELECTRON-IRRADIATED SAPPHIRE CRYSTALS

The kinetics of luminescence decay in electron-irradiated sapphire (al pha-Al2O3) single crystals have been investigated using time-resolved luminescence spectroscopy. The data, observed over timescales from ten s of nanoseconds to tens of milliseconds, characteristically feature a rapid decay of intensity punctuated by discrete plateau regions. Simp le theoretical models, invoking such theories as first- or second-orde r mechanisms, rate laws or power-law dependences, are unable to explai n these features. A theoretical model comprising bimolecular electron- hole recombination, together with unimolecular electron detrapping fro m two discrete traps, qualitatively accounts for these features.