Effects of Annealing Temperature on the Properties of Copper Films Prepared by Magnetron Sputtering

Copper oxide thin films were prepared by a direct-current magnetron sputtering method followed by a thermal annealing treatment at 100-500 ℃. The obtained films were characterized by X-ray diffraction, UV-vis absorption spectroscopy, scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. With the increase of the annealing temperature, it was found that the films transformed sequentially from amorphous to single-phase Cu （100℃）, mixed-phase of Cu and Cu2O （150 ℃）, single-phase Cu2O （200 ℃）, then to mixed-phase of Cu2O and CuO （300 ℃）, and finally to single-phase CuO （400 - 500 ℃）. Further analyses indicated that the Cu/Cu2O thin films and the Cu：O thin films presented no further oxidation even on the surface in air atmosphere. Additionally, the visible-light photocatalytic behavior of the copper oxide thin films on the degradation of methylene blue （MB） was also investigated, indicating that the films with pure Cu2O phase or Cu/Cu2O mixed phases have excellent photocatalytic efficiencies.