Al掺杂的Ca2Si的电子结构和光学性质的研究

First principle calculation electronic structure and optical of orthorhombic Al-dope Ca2Si

摘要:

采用基于密度泛函理论的赝势平面波方法对Ca2Si和Al掺杂Ca2Si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；费米能级插入价带中，Al掺杂Ca2Si变为P型半导体，禁带由未掺杂时的0.26eV变为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。

Abstract:

The band structure，density of states and optical properties of Ca2Siand Al-dope Ca2Si were calculated by the first-principles method. Optimized results Showed that local lattice distorted , volume was increased after induced Al. The Fermi energy moved into valence band. Al-doped Ca2Si of is a P-type semiconductor and the band gap decreased from 0.26eV to 0.144eV.The valance bands of orthorhombic Al-dope Ca2Si are mainly composed of 3P of Si，3P off Al，4s of Ca and 3d，3P of Si. The calculation of Optical properties indicated that after induced Al the static dielectric constant ε1 (0) enlarged，ε2 (ω) moved to a low-energy region, absorption and refractive index increased and reflectivity decreased.