Zn掺杂锐钛矿相TiO_2电子结构的第一性原理计算

First-principle Calculation of Electronic Structure of Zn-doped Anatase TiO_2

采用基于密度泛函理论的第一性原理,计算了Zn掺杂及O空位存在时锐钛矿相TiO2的能带结构、电子态密度、电荷布居和吸收光谱。结果表明:Zn掺杂锐钛矿相TiO2为间接带隙半导体,O空位的存在会引起导带和价带底下移;Zn原子的3d轨道主要对TiO2的价带底有贡献;Zn掺杂使锐钛矿相TiO2在大部分可见光区的光吸收能力增强,并使其在紫外光区发生蓝移;而O空位的存在削弱了其在可见光区的光吸收能力,并增大了其在紫外光区的蓝移程度。

The band structures,electronic density of states, charge population and absorption spectra of Zn- doped anatase TiO2 with and without O vacancy were calculated using first-principles based on density functional theory. The results indicate that Zn-doped anatase TiO2 is indirect band gap semiconductor and O vacancy results in the downward shift of its conduction band and valence band bottom. The 3d orbit of Zn mainly contributes to the valence band bottom. Zn doping enhances the absorption ability of anatase TiO2 in most of visible light region and leads to its blue shift in ultraviolet light region. Meanwhile, O va- cancy impairs the absorption ability of Zn-doped anatase TiO2 in visible light region and strengthens its blue shift in ultraviolet light region.