Influence of sputtering power on microstructures of TiO2 films

Microstructures and properties of TiO2 films, grown by magnetron sputtering on soda-lime glass substrates, were characterized with X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), Raman spectroscopy, photoluminescence spectroscopy (PL) and ultraviolet visible (UV-Vis) transmission spectroscopy. The results show that the sputtering power significantly affects the microstructures and deposition rate of the films. For instance, at a sputtering power lower than 100 W, fhe film is amorphous, whereas at a power higher than 150 W, the film has an anatase phase. As the power increases, the deposition rate linearly increases, the crystallinity improves, and the grains grow with (101) preferential growth orientation. After annealing in O2 at 500°C for 2 hours, its anatase-phased grain size increases by 17% and the film displays good photo-catalytic ability in degradation of methyl blue solution.