N掺杂锐钛矿TiO_2电子结构的第一性原理研究

First-principles study of the electronic structure of N-doping anatase TiO_2

为了研究N掺杂对锐钛矿型TiO2电子结构的影响,进而揭示N掺杂导致锐钛矿型TiO2的禁带宽度变小的机理,对N掺杂TiO2进行了基于密度泛函理论的第一性原理研究.通过对能带、态密度及电子分布密度图的分析,发现在N掺杂后,N原子与Ti原子在导带区,发生了强烈的相互关联作用,致使Ti原子3d轨道上的电子向N原子2p轨道发生移动,使得导带降低了,从而使得TiO2导带的禁带宽度变小.理论预测可以发生红移现象,与实验结果对比分析,理论与实验基本相符.

In order to investigate the effect of N-doping on the electronic structure of anatase Ti02, and discover the mechanism of band gap narmwing after N-doping, we have carried out first-principles calculations based on density-functional theory（DFr） for anatase TiO2 system. Studies of band structures and densities of states and densities of electron distributing show that Ti atoms and N atoms at the conduction band（CB） area, happens a kind of strong correlated interaction, which will lead electrons of Ti atom on the 3d orbit to move to 2p orbit of N atom, and the entire conduction band will move to the Fermi level. Band gap will narrow and the Red Shift electmphoresis will happen. Theoretical result has been compared with the experiment result.