Mn掺杂GaSb的电子结构和光学性质

采用第一性原理方法,交换关联泛函采用局域密度近似,并对计算体系电子的库仑能进行了修正,即采用LDA+U的方法计算研究了Mn掺杂GaSb半导体材料的能带结构和光学性质.研究结果表明:Mn掺杂GaSb体系(Mn-GaSb)的光学性质得到了有效改善,大大提升了对红外光区、远红外光区光子的吸收幅度,其中Mn替代Ga(Mn@Ga)缺陷对改善GaSb半导体材料的光学性能最为明显.Mn掺杂引入的杂质能级有效降低了掺杂体系的禁带宽度,Mn@Ga缺陷的引入增强了GaSb体系的电极化能力和对红外光区光子的吸收.Mn元素的掺入浓度及Mn元素的掺杂位置对Mn@Ga缺陷体系的光学性能均有影响,最佳Mn原子掺杂摩尔比为12.5%,此时Mn@Ga缺陷体系的光学吸收谱在红外光区的吸收幅度最大,同时均匀掺杂避免了光生电子-空穴对复合中心的形成,有效提高了GaSb半导体材料对红外区、远红外区光子的吸收转换效率和GaSb半导体材料的光催化性能.

Electronic structures and optical properties of Mn doped GaSb

We use the LDA+U method of the first-principles calculation to calculate the band structures and optical properties of Mn doped GaSb semiconductor material. The computed results revealed that Mn can increase the absorption amplitude of Mn doped GaSb(Mn-GaSb)semiconductor system in the infrared and far-infrared region. Moreover, Mn substituted Ga(Mn@Ga)defect can improve the Mn-GaSb’s photocatalytic performances effectively. The impurity level induced by Mn can reduce the band gap of the doped system effectively. Compared with that of undoped GaSb system, the static dielectric constant of the function in the Mn-GaSb system is also heighted. The optical properties of Mn@Ga doped system are not only related to the molar concentration of Mn atoms, but also to the uniform Mn atoms. Our results show that the uniform Mn can prevent the formation of electron-hole pairs recombination centers, and the optical absorption peak and absorption range of the Mn-GaSb system are both the biggest in the infrared region with the Mn molar concentration being 12.5%.