Investigation on the electrical properties of metal-Cd_0.9Zn_0.1Te contacts

The electrical properties of different metal-cadmium-zinc-telluride (CdZnTe) contacts produced by sputtering deposition method are investigated. The results of current-voltage and SEM analyses show that Au is the most suitable electrical contact material, which forms nearly ideal Ohmicity contact with high resistivity p-CdZnTe:In crystals and a 0.95 ± 0.02 eV barrier height with low resistivity ones. Passivation treatment can decrease the leakage current. XPS analyses show that Au atoms diffused into CdZnTe:In during annealing, meanwhile Cd and Te atoms diffuse into the Au contact. Diffused Au atoms do not form any compound with any element in CdZnTe:In crystal, but subsitute Cd sites or occupy Cd vacancies as acceptors. Thus, a heavy p-type doping layer is formed, and M-p⁺-p Ohmic contact is obtained.