Deposition mechanism and characterizations of CuInS₂ film prepared by one-step electro-deposition

CuInS₂ films had been prepared on FTO using a one-step deposition method, with sodium citrate complexing agent. The film was deposited from the solution containing 20 mmol L⁻¹ CuSO₄, 7.5 mmol L⁻¹ In₂S₃O₁₂, 75 mmol L⁻¹ Na₂S₂O₃ and 8.5 mmol L⁻¹ Na₃C₆H₅O₇ for 1200 s. The films were characterized by the UV–visible absorption spectroscopy, SEM, AFM, XRD, XPS methods. By the cyclic voltammetry curves of Cu, S, Cu–S, In, In–S, Cu–In–S, the mechanism of CuInS₂ deposition was gotten, that is, the reduction reaction of Cu and In occured, and then S was under potential deposition.