Growth of Cu2ZnSnS4 thin films using sulfurization of stacked metallic films

We fabricated Cu2ZnSnS4 (CZTS) thin films through sulfurization of stacked metallic films. Three types of Cu–Zn–Sn metallic films, i.e., Cu-rich, Cu-correct and Cu-poor precursor films were sputtered onto Mo-coated glass. The sulfurization of stacked Cu–Zn–Sn alloy films was performed at a relatively high temperature, 570 °C, with S-powder evaporation. CZTS films from Cu-rich and Cu-correct precursors showed a Cu2 − xS phase on the film surface, while CZTS films from Cu-poor precursors didn't show the Cu2 − xS phase. However, all films didn't exhibit any extra secondary phase and exhibited good crystalline textures even with Cu-ratio differences in metallic precursor films. Fabricated CZTS films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman scattering measurements. SEM cross-section images of CZTS films showed that Cu-poor CZTS films were grown with more smooth film surface compared with other types of CZTS films.