The effect of sputtering power on the structure and photocatalytic activity of TiO2 films prepared by magnetron sputtering

TiO2 films were fabricated by direct current reactive magnetron sputtering. The effect of the sputtering power on the film structures, morphologies, and properties was investigated in detail. It is found that the concentration of oxygen impurities increased with increasing sputtering power accompanied by the bandgap (Eg) narrowing and broadening of photoluminescence (PL) peaks. The oxygen impurities were found to mainly play the role of recombination centers, leading to the decrease of photocatalytic activity. Furthermore, the photoconductivity to dark conductivity ratio could be used to evaluate and even predict photocatalytic activity to some extent.