Preparation of Cu2ZnSnS4 films by electrodeposition using ionic liquids

We report a new technique for the growth of Cu2ZnSnS4 (CZTS) thin films. The CZTS thin films were successfully formed by electrodeposition in ionic liquid and sulfurized in elemental sulfur vapor ambient at 450 °C for 1.5 h using Argon as the carrier gas. Experimental data on X-ray diffraction indicated that the film has a kesterite structure with preferred grain orientation along (1 1 2). It is found that the energy bandgap of the film is about 1.49 eV and the optical absorption coefficient is in the order of 104 cm−1. The results are compared to a control film grown by e-beam deposition of elemental stacked layers followed by the same sulfurization process. The data show that the two films have comparable optoelectronic properties indicating that electrodeposition in ionic liquid is a viable process for the growth of CZTS films for applications in photovoltaic device. The XRD results also indicate an absence of the oxide peak in the material, which is commonly found in films grown by electrodeposition in aqueous solutions.