Metal–CdZnTe contact and its annealing behaviors

The electrical properties of different metal–CdZnTe contacts by sputtering deposition method are investigated by current–voltage. The results show that Au is the most suitable electrical contact materials, which forms the nearly ideal Ohmic contact with high resistivity p-CdZnTe crystals. Ohmicity coefficient b is the closest to 1 after 10 min annealing at 333 K, which is analyzed by current–voltage characteristics. XPS analyses show that Au atoms diffuse into CdZnTe during annealing process and Cd and Te atoms diffuse into Au contact. Diffused Au atoms do not form any compound with any element in CdZnTe crystal. PL spectra results of Au deposition on CdZnTe crystals at 10 K show that the inter-diffused donors [Au]3+ recombine with acceptors [VCd]2 during sputtering process. Meanwhile, the intensity of (Dcomplex) peak of with Au contact increases sharply in comparison with un-deposited CdZnTe crystal and donor [Au]3+ and ½Au3þ V2 Cd þcan compensate Cd vacancy [VCd]2 wholly.