Electroplated CuInS₂ and CuInSe₂ layers: Preparation and physical and photovoltaic characterization

CuInS₂ films prepared by electrodeposition from an aqueous solution of Cu⁺ and In³⁺ ions and thiourea, with subsequent annealing in an H₂S atmosphere, were characterized by photoelectrochemical measurements in a polysulfide electrolyte and by scanning electron microscopy and microprobe analyses. Laser scanning of the photocurrent together with microprobe analyses correlated n- and p-type behavior with indium-rich and copper-rich areas respectively. For n-type layers, performance appeared to be determined largely by the morphology of the layers. CuInS₂ layers were also prepared by electrodeposition of a CuIn alloy and subsequent sulfurization in H₂S. The above methods were extended to the preparation of CuIn₅S₈ (by adjustment of the copper-to-indium ratio in the bath) and CuInSe₂ (by heating CuIn films in H₂Se).