高氧空位浓度对金红石TiO_2导电性能影响的第一性原理研究

Effects of the concentration of heavily oxygen vacancy of rutile TiO_2 on electric conductivity performance from first principles study

采用基于密度泛函理论的平面波超软赝势方法研究了纯的和不同高氧空位浓度金红石型TiO2-x(x=0,0.083,0.125,0.167,0.25)超胞的能带结构分布、态密度分布.同时,采用局域密度近似+U方法调准了带隙.结果表明,高氧空位浓度越高,金红石型TiO2的最小带隙越变窄、电子有效质量越减小,自由电子浓度越高,电子迁移率越低、电导率越低.计算结果与实验结果的变化趋势相符合.

The band structures and the total densities of states of pure and the different concentrations of heavily oxygen vacancy of rutile TiO2-x （x = 0, 0.125, 0.25） supercell are studied by using the plane-wave ultrasoft pseudopotential method based on the the density functional theory. Local density approximation ＋U is used to correct band gaps. The results show that the higher the concentration of heavy oxygen vacancy, the narrower the gap of rutile TiO2 is, the smaller the effective mass of electron is, the lower the electron mobility is, and the lower the electron conductivity is. The calculation results are in agreement with the experimental results.