Investigation on the electrical properties of metal–Cd0.9Zn0.1Te 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.