FSEC Photovoltaic Materials Laboratory has developed a photoelectrochemical (PEC) cell using multiple band gap tandem of thin-film photovoltaic (PV) cells and a photocatalyst for hydrogen production by water splitting. CdS/CdTe solar cell, a promising candidate for low-cost, thin-film PV cell, is used as one of the thin-film solar cells in a PEC cell. The back contact has been developed for a CdS/CdTe solar cell which involves the deposition of a primary p-type ZnTe:Cu back contact interface layer followed by the deposition of transparent and conducting ZnO:AI and Ni-Al outer metallization layer. This article presents preparation and characterization of ZnTe:Cu back contact interface layer deposited by hot wall vacuum evaporation (HWVE) technique. HWVE technique has produced highly stoichiometric ZnTe:Cu thin films with cubic phase having {111} texture orientation and produced better transparency in the near infrared region on a glass substrate. (c) 2006 American Vacuum Society.