Temperature dependence of photoluminescence properties of In-doped cadmium zinc telluride

Temperature-dependent photoluminescence (PL) spectra were measured to characterize the In-doped cadmium zinc telluride (CdZnTe, or CZT) crystals along the growth direction in the range of 10 to 60 K. High-resistivity CZT samples with 1.2 ppm In dopant at the tip and low-resistivity samples with 60 ppm In dopant at the heel have been assessed. The PL intensity quenching of D⁰X were fitted with two activation energies for high-resistivity CZT sample and only one activation energy for low-resistivity sample, respectively, suggesting different recombination mechanisms. The C-line was observed in the PL spectra of low-resistivity CZT sample and considered to the results of the isoelectronic complexes, In_Cd–V_Cd–In_Cd, while in high-resistivity CZT sample, shallow donor accepted pair (DAP) transition was identified, and thought to be related to In_Cd–V_Cd. The A-center in PL spectra was observed in low-resistivity CZT sample, which is indicative of more cadmium vacancies. It turns out that indium in low-resistivity CZT sample has not been doped as efficiently as in high-resistivity CZT sample because of the self-compensation.