Low-temperature photoluminescence analysis of the γ-irradiation effect on the defect structure in Ge-doped CdTe single crystals

An influence of different doses (10-500 kGy) γ-irradiation on the low-temperature photoluminescence (LTPL) of germanium-doped (Ge-doped) CdTe crystals was investigated. The following results were obtained: even at the lowest doses (equal to 10 kGy) γ-irradiation leads to the substantial modification of the LTPL of Ge-doped CdTe crystals namely decrease in the intensities of the bound exciton emission lines-D0X, A0X, VDX and increase in the intensities of impurity-related emission lines-band to double acceptor transitions line edA and donor-acceptor pairs recombination line DA. Such changes in the LTPL spectra can be explained by the radiation-induced changes in the concentration of the corresponding luminescence centers due to their interaction with fast electrons created corresponding to Compton's phenomenon. However at the increase in the dose of γ-irradiation the effect of saturation was observed in the dose dependencies of the intensities and Huang-Rhys factor of the all emission lines. Mentioned feature can indicate that studied luminescence centers are formed by the defects with different nature and some of that have increased radiation stability.