Effects of In doping on the properties of CdZnTe single crystals

An intrinsic CdZnTe ingot and an Indium (In) doped CdZnTe:In ingot were grown by the modified Bridgman (MB) method, respectively. The effects of In-doping on the properties of CdZnTe single crystals have been analyzed in detail. Leakage current-bias voltage (I-V) measurement shows that the resistivity of CdZnTe increases three orders after In is introduced into the crystal, because cadmium (Cd) vacancies are effectively compensated by In. The leakage current in CdZnTe:In is stabilized more quickly compared with that in CdZnTe, revealed by leakage current-time (I-t) measurement. IR transmission spectra of both ingots indicate that In-doping results in remarkable reduction of the IR transmission of CdZnTe crystals. Photoluminescence (PL) measurement shows that a new deep-level emission appears, due to an In-related complex, and the acceptor-bound (A0,X) peak disappears in the case of CdZnTe:In. It confirms that Cd vacancies are completely compensated by the In-related complex, which is consistent with the result of the I-V measurement. In addition, the intensity of the donor-acceptor pair recombination (D, A) peak becomes stronger after In is introduced. It indicates that there still exists excess In in the crystal after Cd vacancies are completely compensated.