3C-SiC材料p型掺杂的第一性原理研究

A first principle study on p-type doped 3C-SiC

采用基于第一性原理的密度泛函理论平面波超软赝势法,研究了SiC材料p型掺杂的晶体结构和电子结构性质,得到了优化后体系的结构参数,掺杂形成能,能带结构和电子态密度,计算得到掺杂B,Al,Ga在不同浓度下的禁带宽度.结果表明:随着掺杂B原子浓度的增大,禁带宽度随之减小;而随着掺杂Al,Ga原子浓度的增大,禁带宽度随之增大;在相同浓度下,掺杂Ga的禁带宽度大于掺杂Al,掺Al禁带宽度大于掺B.

The geometrical and electronic structures,the dopant formation energies,lattice constants,band structure and density of states of p-type SiC are calculated by the first principles of plane wave ultra-soft pseudo-potential method based on density functional theory. The band structures of different concentrations of B,Al and Ga are calculated. The results of the electronic structure show that the band gap narrows with the increase of doping concentration of B and the band gap widens with the increase of doping concentration of Al and Ga. At the same concentration the band gap of Ga doped SiC is wider than that of Al doped SiC,the band gap of Al doped SiC is wider than B doped SiC.