CuInSe2 thin films formed by selenization of Cu–In precursors

CuInSe2 (CIS) thin films were grown by selenization of electro-deposited or electroless-deposited Cu–In precursors. Cu–In precursors were formed by layer-by-layer electro-deposition of Cu and In as well as by electroless co-deposition of Cu and In. The major phases in the precursors were found to be Cu11In9 and elemental In. It was found that the stoichiometric CIS phase (CuInSe2) may be formed by selenization of the precursors at temperatures higher than 500°C. The Cu–In precursors as well as CIS films were characterized by X-ray diffraction and scanning electron microscopy. The cubic CIS phase was formed when electroless-deposited Cu–In precursor was selenized, whereas the chalcopyrite CIS or the In-rich phase (CuIn2Se3.5) was formed when the layered precursors were selenized at a high temperature.