Optical property analysis of high-resistivity CZT:In single crystals before and after annealing

In-doped CdZnTe:In (CZT:In) single crystals with high resistivity were annealed by an effective method containing Cd/Zn atmosphere annealing and Te atmosphere annealing. They were mainly measured by IR transmittance and Photoluminescence (PL) spectra. The results indicated Te inclusions were eliminated completely after annealing. Both of the resistivity and IR transmittance decreased notably after Cd/Zn atmosphere annealing, and then increased tremendously after Te atmosphere annealing. For PL measurements, (A⁰, X) disappeared, the intensity of (D⁰, X) peak increased, and FWHM was obviously reduced after annealing. These indicated the crystal quality was enhanced. The donor-acceptor pair peak decreased in annealed CZT:In crystal, which might be due to the dissociation of [V _Cd-In_Cd] complex and the remove of the impurities. Moreover, D_complex peak containing two peaks was caused by Cd vacancy-related (D₁) and dislocation-related defects (D₂) in as-grown crystal. However, after annealing, the intensities of D₁ and D₂ peaks decreased because of the compensation of Cd vacancies and the elimination of Te inclusions, respectively.