Ni掺杂浓度对硅纳米线光电性质的影响

利用基于密度泛函理论的第一性原理，对不同直径和浓度Ni掺杂硅纳米线的形成能、能带结构、态密度和光学性质进行了计算，结果表明：杂质Ni的形成能随硅纳米线直径的减小和掺杂浓度的降低而下降，这说明直径越大的硅纳米线掺杂越困难，杂质浓度越高的硅纳米线越不稳定. Ni掺杂在费米能级附近及带隙中引入杂质能级，其主要来自Ni的3d轨道,杂质能级扩展成杂质带，改变Ni的掺杂浓度可改变硅纳米线的带隙，改善其导电性. 另外，还发现掺杂浓度明显改变了硅纳米线的吸收强度和宽度.

Effects of Ni-doped concentration on electronic and optical properties of silicon nanowires

The formation energies, band structure, density of states and optical properties for Ni-doped silicon nanowires of different diameters and concentration are calculated by first-principles based on density functional theory. The results show that the formation energies of Ni impurity increase as both the diameters and impurity concentration of Ni-doped silicon nanowires increase. It indicates that doping in bigger diameter silicon nanowires is difficult and higher impurity concentrations in silicon nanowires are unstable. The doping of Ni in silicon nanowires introduces impurity level in near Fermi level and the gap. It is mainly contributed by Ni 3d level. Impurity bands formed at high impurity concentration. The band gap of silicon nanowire can be modified by changing Ni-doped concentration and improve its conductivity. In addition, the strength and widening of absorption are obviously changed.