Deposition of photocatalytic TiO2 layers by pulse magnetron sputtering and by plasma-activated evaporation

Crystalline TiO2 thin films, especially layers with predominantly anatase phase, exhibit photocatalytic activities resulting in photoinduced hydrophilic, self-cleaning and antifogging properties. In this paper, a comparison of the photocatalytic properties of layers deposited with two different PVD techniques is given. On one hand, a reactive pulse magnetron sputtering (PMS) system has been used to obtain TiO2 films at dynamic deposition rates from 8 to 50 nm m/min. On the other hand, TiO2 layers were deposited by reactive electron beam evaporation at very high deposition rates between 500 and 1000 nm m/min. An additional spotless arc discharge (Spotless arc Activated Deposition-SAD process) was used for plasma activation to improve layer properties. Photoinduced hydrophilicity was investigated by measuring the decrease of the water contact angle during UV-A irradiation.