Al掺杂SnO2 材料电子结构和光学性质

采用基于第一性原理的线性缀加平面波方法(FP-LAPW),研究Al掺杂SnO₂材料Sn_1-xAl_xO₂ (x= 0,0.0625,0.125,0.1875,0.25)的电子结 构和光学性质,包括能带结构、电子态密度、介电函数和其他一些光学性质.计算结果表明,掺杂Al之后价带上部分折叠态增加,价带宽度发生收缩,对导带底起作用的Sn 5s态减少,使得带隙增宽,且态密度整体向高能方向发生移动.随着Al掺杂量的增加带隙越来越宽,Al杂质能级在导带部分与Sn 5p态电子相互作用逐渐增强,虚部谱中的第一介电峰的强度随掺杂Al浓度增大而减弱.同时,吸收谱及其他光学谱线与介电函数虚部谱线相对应,各谱线均发生蓝移现象,对应带隙增宽,从理论上指出了光学性质与电子结构之间的内在关系.关键词：能带结构态密度光学性质介电函数

Electronic structure and optical properties of Al-doped SnO2

Based on the full-potential linearized augmented plane-wave method (FP-LAPW), we investigated the electronic structures and the optical properties, including dielectric function, absorption spectra, refraction and extinction of Sn_1-xAl_xO₂ (x=0, 0.0625, 0.125, 0.1875, 0.25) via substituting for Sn with Al in SnO₂ supercell. Calculated results show that the introduced Al could induce the band gap widening, and this can be attributed to the increased folded states, which lead to the contraction of the valence band and less Sn 5s states at the bottom of the conduction band. With the increasing of Al concentration, the band gap becomes wider, and the intensity of the first main peaks decreases. All of the optical spectra contain the imaginary part of dielectric function, the absorption spectrum, the refraction, and the extinction show blue shift corresponding to the increasing of the band gaps. Finally, it is expected that our results may inspire the future experimental research.