Lotsko O. Transformation of impurity-defect complexes in CdTe:Cl single crystals subjected to technological treatments

The growth technology of СdTe and СdZnTe single crystals has been developed and manufacturing processes of X- and gama-radiation detectors have been optimized. By the low-temperature photoluminescence method the processes of the impurity-defect complexes transformation in high-resistance cadmium telluride single crystals doped with chlorine have been studied under various technological treatments, namely: microwave irradiation, thermal annealing, gamma irradiation. It has been determined, that 2.45 GHz and 24 GHz microwave treatments of CdTe:Cl single crystals lead to activation of ClTe centers. The activation has been detected by a significant increase of (D0, X)-line intensity in the photoluminescence spectra. Under 30 s microwave treatment of the samples the effect of small doses has been observed, which is manifested in significant increase of the exciton PL integral intensity. The radiation-induced ordering of the subsurface region of single crystals have been found at the doses D = 8 кGy for CdTe:Cl with NCl = 5*10^17 cm^(-3) and D = 20 кGy for CdTe:Cl with NCl = 5*10^19 cm^(-3) respectively. Under thermal treatment of CdTe:Cl single crystals (NCl = 5*10^19 cm^(-3)) in the temperature range below 180 °С no significant changes in excitonic PL have been observed. The absence of the changes proves the thermal stability of the material at T <180 °С.