ANODIC FORMATION OF BINARY AND TERNARY COMPOUND SEMICONDUCTOR-FILMS FOR PHOTOVOLTAIC CELLS

By anodic oxidation of copper sheets in sulfide anion-containing elect rolytes copper chalcogenide semiconductor films suitable for photovolt aic applications can be attained. Anodically chalcopyrite (Cu2S) has b een formed as pure, mechanically stable, homogeneous and adhesive poly crystalline films, consisting of well-developed large crystallites. Cu 2S coated copper sheets were produced with an area of 3 cm x 3 cm. P-n -junctions formed by evaporation of CdS onto the anodically formed Cu2 S films show an energy efficiency of 3.3%. The extension of this proce ss to ternary systems, like copper/indium/sulfur, is likely to be poss ible. A mixture of Cu2S and CuInS2 could be formed by codepositing In2 S3 together with Cu2S. Cu2Se-films with a thickness of up to 1 mu m we re formed by chemical bath deposition.