第一性原理计算Al掺杂的正交相Ca_2Si的电子结构及光学性质  

First-principles calculations on the electronic structure and optical properties of Al-doped orthorhombic Ca_2Si

作　　者：邓永荣[1] 张春红[1] 闫万珺[1] 覃信茂[1] 周士芸[1] 陈少波[1] 

机构地区：[1]安顺学院贵州省高等学校航空电子电气与信息网络工程中心,安顺561000

出　　处：《四川大学学报（自然科学版）》2018年第1期135-140,共6页Journal of Sichuan University(Natural Science Edition)

基　　金：贵州省科学技术厅;安顺市人民政府;安顺学院联合科技基金(黔科合[LH字[2014]7507]);贵州省高等学校航空电子电气与信息网络工程中心资助

摘　　要：采用基于第一性原理方法对Ca_2Si和Al掺杂Ca_2Si的能带结构、态密度和光学性质进行计算.结果表明Al掺杂引起了晶格结构畸变,晶胞体积增大;Al掺杂Ca_2Si使得费米能级插入价带中,Ca_2Si导电类型变为P型半导体,禁带宽度由未掺杂时的0.26减小到0.144eV,价带主要由Si的3p,Al的3p以及Ca的4s和3d共同贡献,导带主要由Si的3p态贡献;光学性质的结果显示,由于Al掺入,ε1(0)值增大,ε2(ω)向低能端移动,吸收系数、复折射率增大,反射率减小.By using the first-principles method, band structure, density of states and optical properties of Ca2 Si and Al-doped Ca2 Si were calculated in this paper. The results show that, after doping A1, the lat- tice structure distorted and the volume of lattice expands. The Fermi energy moved into the valence band, and the conduction type changed into P-type semiconductor, and the band gap decreased from 0.26 to 0. 144 eV. The density of states of valance band near the Fermi energy is mainly composes of Si- 3p, A1-3p, Ca-3d and Ca-4s, and the conduction band near the Fermi energy is mainly composes of Si- 3p. Optical properties calculation indicates that after doping A1, ε1 （0） of Ca2Si increased, ε2 （ω） moved to lower-energy, the absorption and the refractive index increased, while the reflectivity decreased.

关 键 词：Al掺杂Ca2Si 电子结构 光学特性 第一性原理 

分 类 号：O474[理学—半导体物理] O881.1[理学—物理]