P型Mn掺杂TiO₂纳米薄膜的制备及其光电性能研究

Fabrication and Optical-Electrical Properties of P-Type Manganese-Doped Titanium Dioxide Nano-Films

采用射频磁控溅射法以Mn0.8Ti1.2O3固相陶瓷靶为靶材,在石英衬底上制备了Mn掺杂TiO2纳米薄膜,通过XRD、EDS、AFM、XPS、UV-Vis-IR、两探针法和半导体霍尔效应等测试表征技术研究了Mn掺杂对TiO2薄膜的晶体结构、表面化学态和光电性能的影响。结果表明,Mn掺杂TiO2薄膜为p型半导体,随着溅射功率的增加,薄膜的光吸收向可见光方向移动,电导率增加。过量Mn掺杂会导致Mn元素的析出,光吸收性能和电学性能均变差,说明Mn掺杂是TiO2薄膜光电性能改善的根本原因。

Manganese, as a 3d transition metal element, is considered to be one of the potential dopants for TiO2 to adjust the optical-electrical properties of TiO2, aiming to improve the utilization of sunlight, conductivity and carrier mobility of TiO2. The modified TiO2 could then be widely used in the in-telligent photo-catalytic, semiconductor sensors, solar cells, etc. In this paper, we have prepared p-type Manganese-doped TiO2 rutile nano-film on amorphous silica/quartz substrates by radio frequency magnetron sputtering method with a Mn0.8Ti1.2O3 solid ceramic target. XRD, EDS, AFM, XPS, UV-Vis-IR, Two-Probe and Hall effect measurements were used to investigate the influences of Mn doping on the crystalline structure, surface state, optical and electrical properties of TiO2 nano-film. The results have shown that Mn doping could effectively extend the light absorption re-gion of TiO2 from UV to visible light. The doping ratio was tuned by adjusting the sputtering power, the higher the sputtering power, the bigger ratio Mn was doped into TiO2. Electrical conductivity of the thin films increased with increase of Mn doping ratio. Mn precipitated when the sputtering power for Mn0.8Ti1.2O3 reached 150 W, suggesting that there is incorporation limit for Mn in TiO2 lattice. The P type Mn doped TiO2 could be used in various applications such as solar cell, gas sen-sors and photosplitting of water.