CATHODIC ELECTRODEPOSITION OF CUINSE2 THIN-FILMS

In order to study the preparation process of CuInSe2 thin films by a one-step electrodeposition method, thin films of the compound were prepared from aqueous citric acid (C6H8O7.H2O) plating baths onto titanium substrates. During electrodeposition, the bath composition and deposition potential were changed to obtain stoichiometric thin films. In general, close to stoichiometry, layers rich in selenium were observed, and this excess of selenium was removed after heat treatment. Best quality films were obtained after annealing at 400-degrees-C during 15 min. X-ray diffraction showed the formation of CuInSe2 films, of chalcopyrite structure, at heating treatment temperatures higher than 350-degrees-C. Optical measurements showed that the band gap of the deposited material was 0.99 eV.