Improvement of the quality of indium-doped CdZnTe single crystals by post-growth annealing for radiation detectors

A method of appropriate post-growth annealing was successfully developed to improve the crystalline quality of indium-doped CdZnTe (CZT:In). Pure Te and Cd/Zn alloy were used as the annealing sources to reduce Cd and Te inclusions, respectively. Characterizations revealed that the inclusions in both low-resistivity and high-resistivity CZT:In crystals were completely eliminated after annealing. The EPD of dislocations and the full width at half maximum (FWHM) of the X-ray rocking curve for both annealed low-resistivity and high-resistivity CZT:In crystals were decreased. Meanwhile, the average IR transmittances of both crystals were increased. In addition, the (D0,X) peak representing crystalline quality appeared in PL spectra of annealed low-resistivity CZT:In crystal, whereas the intensity and sharpness of this peak were better in annealed high-resistivity crystal. Therefore, the annealed CZT:In crystals can meet the requirements of fabricating room temperature nuclear radiation detectors.

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