Dongmei Zeng

Photoluminescence analysis on the indium doped Cd0.9Zn0.1Te crystal

Photoluminescence spectra are used to characterize high resistivity of In-doped CdZnTe crystal. Shallow level donor-acceptor pair (DAPs) peak at 1.6014eV is found due to shallow donor and acceptor compensation related defects, which forms the [VCd–InCd]− singly negative complex and the neutral complex [VCd–2InCd]. Cd vacancy acceptors are compensated dominantly due to indium doped [InCd]+ donor and Te antisite [TeCd]4+ donor, which improves the resistivity of CdZnTe:In crystal. Energy level model diagram of CdZnTe:In crystal is discussed. Current-voltage measurement results confirm that Cd vacancy compensation by doped indium improves the resisitivity of CdZnTe crystal.

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 D 0 X 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.