Preparation and Optical Properties of CuS Nanofilms by a Facile Two-Step Process

CuS nanofilms were prepared by a facile two-step process including chemical bath deposition of Cu nanofilms first and the subsequent thermal sulfuration step. The composition and structure of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Raman spectroscopy. The optical properties of CuS nanofilms were determined by Ultraviolet-visible (UV-Vis) technique. The results show that the nanofilms composed by Cu spherical nanoparticles were completely transformed to the nanofilms composed by CuS nanosheets when the sulfuration temperature was 350∘C. The light absorption edges of CuS nanofilms exhibit red shift when sulfuration occurred at lower temperature. A plausible growth mechanism related with gas phase reaction for formation of CuS nanofilms was also proposed.