Oxide interfacial layers in Au ohmic contacts to p-type Hg1−xCdxTe

Abstract

Annealed Au contacts to p-type Hg1−xCdxTe with thin interfacial oxide layers exhibit ohmic behavior. These interfacial layers have been produced by plasma oxidizing the Hg1−xCdxTe surface prior to Au evaporation or as a result of electroless Au deposition from AuCl3 which also produces an interfacial layer. We believe this ohmic behavior is primarily a result of the low interface state density at the interfacial layer/Hg1−xCdxTe interface and in addition, a 100 °C anneal promotes a further reduction in the interface state density and thus lowered the contact resistance. In comparison, as-deposited and annealed Au contacts without a thin interfacial layer were rectifying with a large barrier height.