氮掺杂对TiO_2薄膜光学性能的影响

Influences of nitrogen doping on optical properties of TiO_2 film

目的研究氮掺杂对TiO2薄膜的折射率、透过率、吸收光谱和光学禁带宽度的影响,寻找最佳的掺N量,通过掺N来提高TiO2薄膜对可见光的敏感度。方法用射频磁控溅射方法在玻璃衬底上,控制氩气和氮气的流量比,生长出不同氮含量的TiO2薄膜。结果适量地掺杂可以提高薄膜的折射率;氮掺杂的TiO2薄膜的光学吸收边发生了明显的红移现象;可见光吸收带中存在肩峰的根本原因是出现了新的氮的2p能级。结论通过适量的氮掺杂可以有效地减小TiO2薄膜的光学禁带宽度,从而提高TiO2薄膜对可见光的响应和太阳光的利用效率,拓宽了TiO2薄膜在太阳能电池、光催化降解及建筑材料等方面的应用。

Aim To study influences of nitrogen doping on the refractive index,transmittance,absorption spectra and optical band gap of TiO2 thin film to find the best amount so as to enhance the sensitivity to visible light.Methods TiO2-xNx thin films were prepared on glass substrates by RF magnetron sputtering,controlling the flow ratio of argon and nitrogen.Refractive index of the samples,transmission spectra and absorption spectra of thin films were studied,as well as the calculation of band gap.Results The right amount of doping can increase the refractive index of thin films;nitrogen-doped TiO2 thin films have taken place in the optical absorption edge of the red shift significantly from the transmission spectrum and the absorption spectra;the root causes of the exsiting acromion in the visible range absorption band is the emergence of a new N 2p level.Conclusion The adoption of an appropriate amount of nitrogen doping can effectively change the TiO2 thin film optical band gap,thereby enhancing the TiO2 film on the visible light response and the utilization efficiency of sunlight to broaden the TiO2 thin film solar cells in the photocatalytic degradation and construction materials applications.