The Study Of Struture And Properties In V And V/N Codoped TiO₂ Thin Films

Titanium dioxide?TiO₂?is a wide band gap semiconductor.It is widely used in the electronics and photocatalysis industry due to its stable chemical properties,non-toxicity and low cost.Numerous experimental investigations have been performed on TiO₂-based dilute magnetic semiconductors doped with transition metal,which exhibit the ferromagnetic property.In addition,many attempts have been made to optimize the band gap of TiO₂ by doping transition metal in TiO₂,in order to enhance visible light absorption in TiO₂.In this paper,a series of doped TiO₂ films were prepared by pulsed laser deposition with V and N as dopants.The structure,magnetic properties,transport properties and optical properties of thin films were studied.The results are summarized as follows:?1?The Ti_1-xV_xO₂?x=0,0.03,0.05?films were prepared in a high vacuum environment by pulsed laser deposition.Under the high vacuum environment,the introduction of V dopant makes the TiO₂ film transform from anatase to rutile,and the high oxygen partial pressure facilitates the stabilization of anatase TiO₂ film.The V³⁺dominates in the TiO₂ films,which are ferromagnetic at room temperature.With the increase of the film thickness,the saturation magnetic moment of the films is decreased.In addition,all Ti_1-xV_xO₂ films are metallic,and the carrier concentration of films are increased with the decrease of the film thickness.?2?A series of V-doped,N-doped and V/N co-doped TiO₂ films were prepared on a SrTiO₃?100?single crystal substrate by pulsed laser deposition.The structure,magnetic and optical properties of the films were studied.The results show that the films are single crystal anatase structure with good crystallinity,and the solubility of N is enhanced in the V/N co-doped TiO₂ films.The room temperature ferromagnetism is observed in the V-doped and V/N co-doped TiO₂ films,and the saturation magnetic moment of V/N codoped TiO₂ film is higher than V doped TiO₂ film.The greatly enhancement of absorption in visible region and a strongly reduced band gap are observed in V/N co-doped TiO₂ films,which enhances the performance of TiO₂ in photoelectrochemical energy conversion.