Influence of the Nitrogen Concentration on the Photoinduced Hydrophilicity of N-doped Titanium Dioxide Thin Films Deposited by Plasma Sputtering

This work reports the influence of the nitrogen concentration (in the gas discharge) on the hydrophilicity properties of N-TiO2 thin films, deposited at low temperature using DC magnetron sputtering on p-Si [100] substrates at different nitrogen flow rates for a fixed electrical power and working pressure. The photoinduced hydrophilicity effect was evaluated by the surface wettability measured through the contact angle between de-ionized water drop and the film surface. Results show that the photoinduced hydrophilicity effect occurs preferentially in thin films with surfaces more irregular and predominantly anatase [101] crystalline orientation. Moreover, further observed phenomena were analyzed, investigated and discussed.