Effect of passivation of the p-CdTe surface in (NH4)2Sx on the current-voltage characteristics of contacts

The current-voltage ( I–V ) characteristics of contacts to CdTe are studied at 300 and 77 K. The contacts were obtained by chemical deposition of Au on the (111) surface of polycrystalline p -CdTe after etching in bromine methanol and after passivation in (NH 4 ) 2 S x . It is shown that passivation of the surface noticeably linearizes the I–V characteristics at 300 K and only slightly at 77 K. The measurements of the low-temperature photoconductivity of the samples showed that the passivation of the surface in (NH 4 ) 2 S x decreases the surface-state density at the metal-semiconductor interface.