Features of OSL and TL properties of anion-defective corundum crystals exposed to thermo-optical treatment

• Stimulation by light with λ = 460 nm depletes the deep trap and leads to a phototransfer.
• Phototransfer from the deep trap appears as a slow component on the OSL curve.
• Presence of the OSL rise-up or decay depends on the main trap filling degree.
• In phototransferred TL spectra emission at 3.7 eV dominates over 3.0 eV emission.

The results of systematic investigation of the mechanisms and role of phototransfer in TL and OSL processes in α-Al2O3−δ crystals under controlled filling of the main and deep traps depleted at 450 and 720 K, respectively, are presented.Optical depletion spectra of the main and deep traps were measured and compared. It was found that green light stimulation only depletes the main trap, while blue light depletes both the main and deep traps. Optical depletion of the deep trap results in phototransfer of charges that can be realized by 2 mechanisms: either through the main trap to recombination centers or directly to the latter. However, the dominant contribution to the OSL signal is provided by phototransfer through the main trap. It is also found that UV emission at 3.7 eV dominates over F-emission at 3.0 eV in the phototransferred TL spectrum. It is assumed that this UV emission is not related to the F+ centers.