Ga-Doped Nano-TiO2 Thin Films: Preparation, Optical and Electrical Properties

The gallium-doped TiO2 thin films were deposited on glass substrate by Radio Frequency(RF) magnetron sputtering, and annealing treated in vacuum for 2 h at 550 degrees C. The films were characterized using XRD, SEM, UV-Vis transmission spectraoscopy. XRD results show that the TiO2 thin films change to mixed crystal with sputtering power of 200 W at room temperature, and the grains have grown up trend after annealing. SEM results reveal that Ga-doped thin films have a more uniform and smaller particle size distribution with an average size of 30 nm. The surface morphology is land-like. UV-Vis transmission spectra show that. the absorption edge of the Ga-doped thin films occurs obviously red-shifted, and even a red-shift of 10 similar to 50 nm is found after annealing. The films have good hydrophilicity as evidenced by contact angle measurement and calculation. The samples exibit good photocatalytic activity as shown by the degradation rate of 71.8% for methylene blue solution after 8 h irradiation under low power UV lamp(15 W).