P掺杂正交相Ca_2Si电子结构及光学性质的第一性原理计算

Electronic Structure and Optical Properties of Orthorhombic P-doped Ca_2Si Calculated by the First-principles

采用基于密度泛函理论第一性原理超软贋势平面波方法系统计算了Ca2Si及P掺杂Ca2Si的电子结构、光学性质,分析了P掺杂对Ca2Si的能带结构、电子态密度、光学性质的影响.计算结果表明:掺入P后Ca2Si的能带向低能方向偏移,禁带宽带为0.557 95eV,价带主要由Si的3p,P的3p以及Ca的4s、3d电子构成,导带主要由Ca的3d电子贡献.通过能带结构和态密度分析了P掺杂正交相Ca2Si的复介电函数、折射率、反射谱、吸收谱和能量损失函数,结果表明P掺杂增强了Ca2Si的光利用率,说明掺杂能够有效改变材料电子结构和光电性能,为Ca2Si材料光电性能的开发、应用提供理论依据.

The energy band structures, density of states and optical properties of Ca2 Si and P-doped Ca2 Si were calculated systemically by density functional theory of the first-principles pseudo potential wave method. The results show that the energy bands of P-doped Ca2 Si move to lower energy but it＇s still a direct semiconductor with the band gap of 0. 557 95 eV. The valance bands of orthorhombic P-doped Ca2Si are mainly composed of 3p of Si, 3p of P and 4s, 3d of Ca. The conduction bands mainly composed of 3d of Ca. Furthermore the static dielectric constant, refractive index, the reflectivity, the absorption and the loss function of orthorhombic of P-doped Ca2Si were analyzed in terms of the calculated band structure and densities of states. The results show that the electronic structure and optical properties of Caz Si can be effectively modulated by P-doped.