In3+-doped CuS thin films: physicochemical characteristics and photocatalytic property

Semiconducting Indium-doped copper sulfide thin films were deposited on glass substrate by a simple and economical chemical bath deposition technique. The depositions were carried out for 40 min. The electrical studies namely resistivity, resistance, and sheet resistance of CuS and CuS: In were carried out using four-point probe apparatus. The structural, optical, and morphological characterization were studied and compared with those of CuS: In with the bare CuS thin films. XRD studies confirmed that all the prepared thin films have the hexagonal structure of copper sulfide without any secondary phase after doping and the crystallite size was found to be decrease from 69 to 53 nm. Optical absorption analysis of samples shows a red-shift in the band edge of In: CuS thin films relative to CuS film so that the bandgap energy was decreased from 1.95 eV to 1.86 eV. The functional groups present in the CuS and In: CuS samples were confirmed by FTIR and FT-Raman frequency assignments. Morphological studies of CuS and CuS: In are interpreted using SEM and constituents present in the prepared thin films are viewed by EDS. Further the photocatalytic properties of the prepared films were studied by degrading methylene blue (MB) and rhodamine B (RhB) textile dyes. Maximum degradation efficiency achieved by the photocatalyst is to be 95% and 93% respectively for MB and RhB.