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采用第一性原理超软赝势平面波方法研究了不同浓度N掺杂对锐钛矿相TiO2的晶体结构、电荷布局、能带结构、态密度及光学特性的影响。计算结果表明,N掺杂会引起TiO2晶格畸变,晶体体积、原子间键长及电荷分布随掺杂量发生变化。N掺杂使轨道分裂,在价带顶引入杂质能级,使TiO2的禁带宽度变窄,掺量越大带隙越小。掺杂使TiO2由间接半导体转变为直接半导体,光吸收带边同时出现红移和蓝移。在计算范围内,随着掺杂浓度的增大,可见光吸收强度逐渐增强。
The first-principle ultra-soft pseudopotential plane wave method was used to study the effect of different concentrations of N-doping on the crystal structure, charge distribution, band structure, density of states and optical properties of anatase TiO2. The calculated results show that N doping can cause the lattice distortion of TiO2, and the crystal volume, atomic bond length and charge distribution change with the doping amount. N doping to make orbit splitting, introducing impurity level at the top of the valence band to narrow the forbidden band width of TiO2, the larger the dosage is, the smaller the bandgap is. Doping makes the transition from indirect semiconductors to direct semiconductors, with red-shifted and blue-shifted photons. In the calculation range, with the doping concentration increases, the visible light absorption intensity gradually increased.