Cd、Sr掺杂Mg2Ge电子结构和光学性质的第一性原理研究

此文用基于密度泛函理论(DFT)的第一性原理计算方法,分别研究了本征、掺Cd、掺Sr的Mg₂Ge的能带结构、电子态密度和光学性质.研究结果表明,本征Mg₂Ge是一种间接带隙半导体,带隙值为0.228eV.Sr的掺入使其变成带隙为0.591 eV的直接带隙半导体,Cd掺杂Mg₂Ge后表现出半金属性质.掺杂后的主要吸收峰减小,吸收谱范围增加.在可见光能量范围内,掺杂的Mg₂Ge有更低的反射率,对可见光的利用率增强.此外,掺杂还提高了高能区的光电导率.

First principles calculations on the electronic structures and optical properties of Cd and Sr doped Mg2Ge

Using the first-principles method based on density functional theory (DFT), the electronic structures, electronic densities of states and optical properties of intrinsic Mg2Ge, Cd-doped and Sr-doped Mg2Ge were calculated. The research results indicate that intrinsic Mg2Ge is an indirect band gap semiconductor with band gap value of 0.228 eV. The value becomes 0.591 eV with band gap turned to direct after Sr doped. Cd-doped Mg2Ge exhibits the feature of semimetal. The predominate absorption peak is decreased, whereas the scope of optical absorption spectra is increased after doped. In the visible light range doped Mg2Ge has lower reflectivity than intrinsic Mg2Ge, which enhances the utilization rate of visible light. In addition, the optical conductivity in high energy region has improved after doped.