ELECTRODEPOSITION OF CU-IN ALLOYS FOR PREPARING CUINS2 THIN-FILMS

Copper-indium alloys were prepared by electroplating from citric acid (C6H8O7·H2O) baths onto Ti substrate. Formation of the alloys was carried out by direct codeposition of the elements and by sequential electrodeposition of copper and indium. Studies of the alloy formation by electrochemical measurements and X-ray diffraction were performed. The presence of Cu7In4 in direct deposit as well as in sequentially electrodeposited material was observed during the alloy formation. The as-deposited layers were heated in H2S. X-ray diffraction showed the annealed layers to be CuInS2 with the chalcopyrite structure, where the CuIn5S8 phase was included during the annealing process. Photoelectrochemical characterization of the samples allowed us to determine the photoconductivity which is related with the Cu/In ratio in the samples. The energy gap for CuInS2 photoelectrodes in polysulphide solution was 1.57 eV. © 1990.