The growth of CuS thin films by Spray Pyrolysis

Thin films of CuS (covellite) were deposited onto TCO (SnO2:F) glass by Spray Pyrolysis (SP) technique. Aqueous and water:alcohol (ethanol, 1-propanol) solutions of copper(II) chloride and thiourea with different Cu/S molar ratio have been used as precursors. The substrate temperature was varied from 185°C to 285°C. The structural and the morphological characterization of the films has been carried out by Raman spectroscopy and Scanning Electron Microscopy. The X-Ray Diffraction analysis of as-grown films showed the single-phase covellite, with hexagonal crystal structure built around three preferred orientations corresponding to (102), (103) and (110) atomic planes. The dense morphology of CuS films with large crystallites/aggregates suggest that crystal growth is the limiting step in the films deposition, at 235 °C and at 285 °C, from precursors’ solution containing water or mixtures of water:alcohol as solvents. The growth of CuS thin films by spray pyrolysis is favored by increasing both the alcohol concentration and the deposition temperature.