Influence of processing parameters on the preparation of CuInS2 thin film by one-step electrodeposition as the solar cell absorber

With the application of a potential of − 0.8 V, CuInS2 thin film was electrodeposited on stainless steel substrate by one step method in sulfurate bath, consisting of 10 mM CuSO4·5H2O, 10 mM In2(SO4)3 and 200 mM Na2S2O3 with the pH value of 2.0. The influence of bath aging conditions, deposition time and the heat treatment on the morphology, stoichiometric proportion and structure of the film were studied by scanning electronic microscopy and X-ray diffraction. Also, the photoelectric performance of the as-received film was characterized by electrochemical approach and ultraviolet–visible spectrophotometer. A highly (112)-oriented chalcopyrite structure was achieved in as-deposited samples. It was proved that there existed a critical bath aging time of 10.5 h, an optimal deposition time of 40 min at 50 °C and an annealing temperature of 400 °C, which were favorable to produce a chalcopyrite thin film. Based on the Mott–Schottky curve, the flat band potential of 0.89 V and the acceptor density of 1.01 × 1019 cm− 3 were obtained. The band gap of the as-deposited film was determined with the value of about 1.50 eV.