Thermo-stimulated luminescence of x-ray- and alpha-irradiated yttria-stabilized zirconia

Abstract : Yttria-stabilized zirconia single crystals (with 9.5 mol% Y2O3) were irradiated with x-rays and particles. Thermally stimulated luminescence (TSL) data show a main broad peak centred at 500-550 K in the glow curves of all irradiated samples. The TSL peak maximum temperature is consistent with the characteristic recovery temperature (450 K) of colour centres (T centres) deduced from isochronal annealing curves measured by electron paramagnetic resonance (EPR) spectroscopy. However, the trap-depth energies (ranging between 0.8 and 1.2 eV) deduced from the initial rise of partially cleaned TSL peaks (and from a rough approximation using Urbach's formula) are much larger than the activation energies for defect recovery of 0.3 eV deduced from the EPR data. A second TSL peak centred at 350-450 K found in freshly irradiated samples is seen to decay substantially in aged samples. The processes involved in TSL are discussed in relation to the defect annealing processes, and available defect-level energy and TSL data