Abnormal negative thermal quenching of photoluminescence in CdMnTe: In crystals

摘要

Temperature-dependent photoluminescence (PL) properties of indium-doped CdMnTe (CMT:In) crystals were investigated. Four emission peaks of the tip crystal and three emission peaks of the tail crystal from as-grown CMT:In ingot were observed at low-temperature (10 K) PL spectra, respectively. From 20 K to 40 K, PL intensity of the deep defect-related emission peak (D-complex) increased with temperature, showing a negative thermal quenching effect for the tip crystal. Interestingly, from 60 K to 80 K, negative thermal quenching phenomena were found for three emission peaks, the neutral donor-bound exciton (D-0,X), the donor-acceptor pair DAP and D-complex, in PL spectra of the tail crystal. ICP-MS test, IR transmittance, I-V measurement and IR microscope revealed that the CMT:In crystals with many impurities and defects tended to cause abnormal photoluminescence. Specially, impurities mainly resulted in the formation of intermediate states and were responsible for the negative thermal quenching behavior. The abnormal PL behavior can be explained by intermediate states.