Emission properties of ZnSe scintillation crystals co-doped by oxygen and aluminum

Photoluminescence properties of ZnSe scintillation crystals co-doped with oxygen and aluminum are studied together with conventional tellurium-doped ZnSe scintillators, for comparison, under continuous-wave and pulsed excitation in the temperature range from 8 to 300 K. A strong enhancement of the low-energy component in the deep-level-related emission is observed as the temperature approaches the room temperature. Fitting of the experimentally observed luminescence decay with calculations of the decay due to donor–acceptor pair recombination revealed that the increased density of recombination centers is responsible for the enhanced low-energy emission component in the co-doped crystals. The significant thermal enhancement of this spectral component is explained by carrier detrapping from the trapping centers abundant in the co-doped crystal due to a large concentration of aluminum impurities.