Nd掺杂金红石TiO_2的电子结构及光学性质的研究

First-Principles Calculation of Electronic Structure and Optical Properties of Nd-doped Rutile TiO_2

采用密度泛函平面波超软赝势方法,系统研究了Nd掺杂前后金红石相TiO2的电子结构变化,计算结果表明:Nd掺杂使TiO2的电子态发生重新分布,分能带明显增加;在导带的下方出现了一些新的电子态,分波态密度的结果进一步证实,这些新的态归属于Nd 4d轨道;金红石TiO2的带隙引Nd 4f态的引入而明显降低,并导致材料的带隙减小;Nd掺杂前后金红石相TiO2的紫外-可见漫反射光谱的测试结果表明Nd掺杂TiO2的紫外可见吸收光谱发生红移。

The geometric structure, total densities of states and band structures of doped and undoped rutile TiO2 were studied by the plane wave ultra-soft pseudo-potential technique based on the density function theory. The optical properties were investigated by UV-visible reflection spectrum. The calculation shows that N doping results in the redistribution of electron state and increase of energy bands of the rutile TiO2. Some new electron states emerge below the conduction band, which are confirmed to belong to Nd 4d orbit. On the other hand, the conduction band is considerably downward, and the position of valence band changes a little, making the band gap narrow. Red shift occurs in the ultraviolet-visible diffusive reflectance spectra of Nd doped TiO2.