A series of CdS/ZnxCd1minus;xTe heterojunctions have been prepared by evaporation of CdS onto singlehyphen;crystalphyphen;type ZnxCd1minus;xTe substrates withx=0, 0.1, and 0.3. The junction properties have been evaluated as a function ofx, the substrate surface preparation, and the substrate temperature during CdS deposition. The junctions with the best quality correspond to those formed on stoichiometric ZnxCd1minus;xTe surfaces. Even with the optimum surface preparation, an increase inxresults in an increase in the reverse saturation current and a decrease in the openhyphen;circuit voltage. Current versus voltage measurements as a function of temperature indicate that the junction transport can be described by thermally assisted tunneling. Illumination increases the junction transport current, an effect that persists for a measurable time after cessation of illumination. Both results can be described in terms of the effects of interface states, controlling tunneling/recombination and the width of the depletion layer in the ZnxCd1minus;xTe.
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