Effect of complexing agent on the morphology and annealing temperature of CZTS kesterite thin films by electrochemical deposition

Cu2ZnSnS4 kesterite thin films have been electrochemically deposited on indium doped tin oxide (ITO) coated glass substrates from an aqueous electrolyte solution containing CuSo4, ZnSo4, SnSo4 and Na2S2O3 precursors in one step deposition. The purpose of this work is to reduce the cost of fabrication of CZTS thin films with good crystallinity by investigated the effect of complexing agent Na2So4 with Na3C6H5O7 on annealing temperature of CZTS thin film. Based on the results it was found that good crystal structure was achieved at temperature 350 °C, that is below the reported annealing temperature in the literature. The electrodeposition process was maintained at room temperature with a working potential set at −1.05 V vs. Ag/AgCl. The annealed CZTS films were characterized by X-ray diffraction revealed the formation of a crystalline phase CZTS with major and intense peaks. Scanning electron microscopy (SEM) analysis stick to EDS show compact and uniform surface morphology with a spherical crystalline geometry and near stoichiometry metal atomic ratio for the different samples prepared. Atomic force microscopy (AFM) analysis confirms these results. From UV–visible spectroscopy, bandgap of around 1.5 eV was estimated for the kesterite thin films.