Preparation Of Ta, N Doped TiO₂ Thin Films By DC Magnetron Sputtering Method And Studies On Hydrophilic Property

TiO2 thin films attract much attention as self-clean materials because of the super-hydrophilicity. However, the application of TiO2 was confined by the UV response. The primary task for high hydrophilic performance is realization visible light response. In this investigation we prepared N-doped TiO2 and Ta, N co-doped TiO2 by DC reactive magnetron sputtering. The cathode was a Ti target (99.99%) and Ta blocks (99.99%), the reaction gases were pure Ar, N2 and O2 respectively. SiO2-coated layer was prepared with SiO2 target (99.99%) by radio-frequency magnetron sputtering under pure Ar and O2. Doped films were prepared in room temperature and annealed in air. Doped TiO2 characterized by the XRD, XPS, AFM, UV-Vis, and hydrophilic measurements.The main research results are as follows:(1) N-doped TiO2 films heated to 400℃ for 1h appear Anatase structure. Higher annealing temperature and longer annealing time have little influence on crystal grain size;(2) UV-Vis absorption of N-doped TiO2 and Ta, N co-doped thin films suggest that N doping improve the visible light response, Ta and N co-doping induce a red shift of the absorption peaks, and the increase of absorption range;(3) XPS measurements show that Ta and N exist in Ta5+ and N3- respectively. A sign of -OH absorption is observed in the co-doped film, which indicate a good hydrophilicity;(4) N-doped and Ta, N co-doped TiO2 films have low initial contact angles. Contact angle of Ta, N-doped TiO2 film decrease more quickly than N-doped TiO2 film, it can reach 4° within 20 minutes;(5) Hydrophilicity holding time is extended by the pre-coating of SiO2.