Al掺杂浓度对CrSi_2电子结构及光学性质的影响

Effect of Al Doping Concentration on Electronic and Optical Properties of CrSi_2

采用基于第一性原理的赝势平面波方法,对不同Al掺杂浓度CrSi2的几何结构、能带结构、态密度和光学性质进行了计算和比较。几何结构和电子结构的计算表明:Al掺杂使得CrSi2的晶格常数a和b增大,c变化不大,晶格体积增大;Cr(Si1-xAlx)2仍然是间接带隙半导体,掺杂使得费米面向价带移动,且随着掺杂量的增大而更深地嵌入价带中,费米能级附近的电子态密度主要由Cr的3d态电子贡献。光学性质计算表明,随着掺杂量的增大,Cr(Si1-xAlx)2的静态介电常数、第一介电峰、折射率n0逐渐增大,平均反射效应减弱,表明Al掺杂有效增强了CrSi2对光的吸收,能够提高其光电转换效率。计算结果为CrSi2光电材料的应用和设计提供了理论指导。

By using pseudo-potential plane-wave method of the first principle based on the density function theory,geometrical structure,electronic structure and optical properties of Al-doped CrSi2 are calculated and analyzed.The calculated results on geometrical structure and electronic structure show that the lattice constant a and b increase while c has little change,the volume of lattice expands,the band structure is still indirect and the Fermi energy moves into the valence band deeper and deeper with Al increase from 0 to 0.3333,the density of electronic states near the Fermi energy level is mainly composed of Cr-3d.Optical properties calculation indicates that after doping Al,static dielectric constant,the first peak of ε2（ω） and refractive index n0 increase,the average reflective effect decreases,the light absorption of CrSi2 effectively enhances,and then improves the photoelectric conversion efficiency after doping Al.These results offer theoretical guide for design and application of optoelectronic material of CrSi2.