镍掺杂硅纳米线电子结构和光学性质的第一性原理研究

First-principles study of electronic and optical properties of Ni-doped silicon nanowires

利用基于密度泛函理论的第一性原理计算,对镍掺杂硅纳米线的结构稳定性、电子与光学性质进行了研究.结果表明:Ni容易占据硅纳米线表面的替代位置.镍掺杂后的硅纳米线引入了杂质能级,杂质能级主要来源于Ni的3d电子的贡献.由于Ni的3d态和Si的3p态的耦合作用,使禁带宽度变窄.掺杂后的硅纳米线在低能区出现了一个较强的吸收峰,且吸收带出现宽化现象.

Structural stability,electronic and optical properties of Ni-doped silicon nanowires are investigated by first-principles calculations based on the density functional theory.The results show that Ni can preferentially occupy substitutional sites near the surface of silicon nanowire.The doping of Ni atom in silicon nanowire introduces the impurity levels.The impurity level is mainly contributed by Ni 3d orbital.The decrease of the band gap results from the coupling of Ni 3d and Si 3p states.A strong absorption peak occurs in the low energy region of Ni-doped silicon nanowire,accompanied by the widening of the absorption band.