第一性原理计算Ti掺杂CrSi2的光电特性简

采用第一性原理方法对Ti掺杂CrSi2的几何结构、电子结构、复介电函数、吸收系数、反射谱、折射率和光电导率进行了计算,对Ti置换Cr原子后的光电特性变化进行了分析.结果表明:Ti置换Cr原子后,晶格常数a,b和c均增大,体积变大;Ti的掺入引入了新的杂质能级,导致费米能级插入价带中,Cr11TiSi24变为p型半导体,带隙宽度由未掺杂时的0.38eV变为0.082eV,价带顶和导带底的态密度主要由Cr-d和Ti-d层电子贡献;与未掺杂CrSi2相比,Cr11TiSi24的介电峰发生了红移,仅在1.33eV处有一个峰,而原位于4.53eV处的峰消失;吸收系数,反射率和光电导率明显降低.

First principle calculation of optical-electrical characteristics of Ti-doped CrSi2

A detailed theoretical study on geometric structure, electronic structure, complex dielectric function of Ti-doped CrSi2 was performed based on the first -principles method. The results show that after doping Ti, the lattice constants a, b, c and volume are all increased. New impurity energy levels are induced in the forbidden band, and the Fermi energy moved into valence band. Cr11TiSi24 is a p-type semiconductor and the band gap decreased from 0.38eV to 0.082eV. Density of states of the valence band top and conduction band bottom are mainly composed of Cr-d and Ti-d. Compared with pure CrSi2, the dielectric peak of Cr11TiSi24 makes red shift and only a peak appears at 1.33eV, while the peak at 4.53eV is disappeared. Absorption, reflectivity and conductivity of Cr11TiSi24 are obviously decreased.