CuInSe2 precursor films electro-deposited directly onto MoSe2

Mo/MoSe2 thin film electrodes formed by selenisation of molybdenum are investigated as chemically robust substrates for the electro-deposition of InCu precursor layers for CuInSe2 (CISe) solar cell absorber films. Exposure of molybdenum films to selenium vapour at 550 °C produces thin and chemically robust heterostructures of Mo/MoSe2. These films exhibit the characteristics of a degenerate semi-conductor and provide close to metallic electrical conductivity for electro-deposition processes in both acidic and alkaline aqueous media. The Mo/MoSe2 films are characterised by cyclic voltammetry for the reduction of in aqueous 0.1 M KCl, for the reduction of 0.1 M In3+ in aqueous 0.5 M LiCl pH 3, and for the reduction of 0.1 M Cu2+ in aqueous 3 M NaOH with 0.2 M d-sorbitol. In all three cases well-defined and reversible voltammetric responses are observed. For the formation of CISe films initially In3+ is deposited potentiostatically followed by electro-deposition of Cu2+ and selenisation at 550 °C in selenium vapour. Mechanically stable CISe films are produced and preliminary photo-electrochemical data demonstrate the effects of changing the stoichiometry.