氮掺杂浓度对氮掺杂PbTiO3电子结构和光学性能的影响

用第一性原理计算研究了不同N掺杂浓度的P型N掺杂PbTiO3的电荷密度差分、能带结构、态密度和光学性质。用N原子取代PbTiO3中的O原子后，PbTiO3的价带向高能级发生移动，费米能级进入价带顶部。随着N掺杂浓度的增加，能带带隙值变窄，结构稳定性变差。掺杂浓度2.5 at%时，N掺杂PbTiO3显示最好的P型导电性和最强的可见光吸收。N掺杂PbTiO3在半导体光电器件和光催化领域具有重要的应用价值。

Effects of N concentration on electronic and optical properties of N-doped PbTiO3

The p-type N-doped PbTiO₃ with different doping concentrations have been studied by first-principles calculations. The charge density differences, band structures, density of states and optical properties have been investigated. After an oxygen atom is substituted by a nitrogen atom in the crystals, the valance bands move to high energy levels and the Fermi energy level gets into the top of the valance bands. Results show that the values of the band gaps are decreased and the stability is weakened when the N concentration increases. The 2.5 at% N-doped PbTiO₃ shows the best p-type conductivity and the visible-light absorption can be enhanced most at this doping concentration, which is necessary in semiconductors or photocatalysts.