Tl掺杂对InI禁带宽度和吸收边带影响的第一性原理研究

采用基于密度泛函理论框架下的第一性原理平面波超软赝势方法,建立了未掺杂与不同浓度的Tl原子取代In原子的In1-xTlxI超胞模型,分别对模型进行了几何优化、能带分布、态密度分布和吸收光谱的计算.结果表明:Tl掺杂浓度越小,In1-xTlxI形成能越低,晶体结构越稳定;Tl的掺入使得InI体系导带向高能方向移动,而价带顶位置基本没变,导致禁带宽度变宽,InI吸收光谱出现明显蓝移现象.

First-principle study on the effects of Tl doping on the band gap and the band-edge of optical absorption of InI

According to the density functional theory, using first-principles plane-wave ultrasoft pseudopotential method, models for a pure InI and different concentrations of Tl-doped InI are set up, and the geomertry optimizations for the modes are carried out. The total density of states, the band structures and the optical absorption are also calculated. The results show that the smaller the doping concentration of Tl, the smaller the formation energy of InI is, thus the more stable the crystal structure is. The Tl doping causes the bottom of conduction band shift to a higher energy, while the location of the top of valence band has no change. This makes the band gap of InI broadened, and the absorption spectrum obviously blue-shifted.
Keywords： Tl doped InI electronic structure absorption spectrum first-principles