Sb掺杂SnO_2的电学性质和光学性质密度泛函理论研究（英文）

Density Functional Theory Study on the Electronic Structure and Optical Properties of Sb-doped SnO_2

基于平面波赝势密度泛函理论,采用局域密度近似(LDA)方法研究了Sb掺杂Sn O2的电子结构和光学性质。计算结果表明,与本征Sn O2比较,Sb掺杂Sn O2的性质,包括能带结构、态密度、电荷密度及光学性质等均随Sb的掺杂浓度变化。Sb掺杂相比本征Sn O2的带隙要窄,带隙随Sb掺杂浓度的增加逐渐变窄,并且浅施主杂质能级逐渐远离导带底。Sb掺杂改变了Sn O2可成键性质,随着掺杂浓度的增加,共价性减弱,金属性增强。光学性质计算结果显示随着掺杂浓度的增加,态密度和介电函数虚部向低能方向移动,发生了明显的红移现象,这从理论上揭示了电子结构和光学性质之间的内在关系。

The electronic structures and optical properties of Sb-doped SnO2 are studied by first principle calculation based on density functional theory （DFT）. The computed results show that, with the increase of Sb doping concentration, the Fermi energy level passes through conduction band, and the band gap is narrower in succession, meanwhile, the energy level of shallow donor impurity is shifted away from the conduction band bottom, which makes the conductivity enhanced. The calculated results of charge density indicate that Sb-doping can change the property of SnO~ bond formation, which makes the covalent weakened and the metallicity enhances with the increase of Sb doping concentration. The calculated results of optical properties show that the imaginary part of the dielectric function has a red shift like the total density of state （TDOS） with the increase of Sb doping concentration, which indicates the internal relationship between electronic structure and optical properties theoretically.