Eu、N掺杂锐钛矿相TiO_2电子结构及光学性能的第一性原理研究

First-principles Study on the Electronic and Optical Property of N and Eu Doped Anatase TiO_2

利用第一性原理赝势方法计算了纯TiO_2及TiO_2掺杂N、Eu元素后的电子能带结构、态密度和光学性质.基于计算结果的分析发现：随着N、Eu元素的掺杂,TiO_2的能带结构发生了较大的变化,带隙宽度减小,产生杂质能级,费米能级越过价带,显现出明显的p型半导体特征;纯TiO_2在2.127 e V附近时,有吸收谱的出现,因此其对可见光吸收的能力很微弱;N元素掺杂后,体系在0.937e V附近有吸收谱的出现;Eu元素掺杂后,体系在1.64～3.19 e V（对应波长为390～770 nm）的可见光区域内,出现吸收峰,有效地改善了锐钛矿相TiO_2晶体对可见光的响应.

The use of first-principles pseudo-potential method calculated anatase TiO2 before and after N and Eu doped of the electronic band structure, density of state and optical properties. The calculation results show that, as the N and Eu doped, the band structure of TiO2 occurred big changes, the width of the band structure decreased, impurity energy levels appeared, Fermi level crossed valence band, which showing significant p-type semiconduc- tor characteristics; after N and Eu doped, around 2.127 eV, anatase Ti02 has found absorption spectrum, so its abili- ty of absorb visible light was very weak. After N doped, around 0.937 eV, anatase TiO2 has found absorption spec- trum, after Eu doped, anatase TiO2 at 1.64-3.19 eV （corresponding to a wavelength of 390-770 nm）, within the visi- ble light region has found absorption peak, which effectively improved the anatase TiO2 crystals corresponding tovisible light.