Cu/TiO2 thin films prepared by reactive RF magnetron sputtering

Abstract

Cu/TiO2 thin films were deposited on glass substrates by reactive RF magnetron sputtering technique. Crystalline structure, surface morphology and electronic structure were studied using X-ray diffraction (XRD), field emission scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy (XPS). Transmittance and absorptance of these films were characterized by UV–Vis spectroscopy. XRD patterns demonstrate that TiO2 films deposited on glass substrate at 300 °C are observed to be in pure anatase phase, whereas Cu/TiO2 films are amorphous in nature at 300 °C substrate temperature. The crystallinity of Cu/TiO2 thin films decreases with increasing the dopant concentrations of Cu in TiO2 films. XPS studies show that Cu is in +2 oxidation state in all films. The optical band gap of Cu/TiO2 films decreases from ~3.3 to ~2.0 eV with the increase in the copper concentration. Further, antimicrobial studies of Cu/TiO2 films with ~3.9 at.% Cu exhibit high transmittance and best antimicrobial activity against E. coli and S. aureus compared to other doped films.