Ag掺杂AlN半导体光电性质的第一性原理研究

First-principles Study of Optical and Electronic Properties of Ag Doped AlN Semiconductors

采用基于密度泛函理论的第一性原理平面波超软赝势法,对Ag掺杂AlN 32原子超晶胞体系进行几何结构优化,计算并分析体系的电子结构、磁性和光学性质.结果表明:Ag掺杂后,Ag4d态电子与其近邻的N2p态电子发生杂化,引入杂质带形成受主能级,实现p型掺杂,使体系的导电能力增强,同时表现出金属性和弱磁性,其净磁矩为1.38μв.掺杂形成的N-Ag键电荷集居数较小,表现出强的离子键性质.掺杂后体系的介电函数虚部和光吸收谱在低能区出现新的峰值,同时复折射率函数在低能区发生变化,吸收边向低能方向延展,体系对长波吸收加强,能量损失明显减小.

Geometrical structure of Ag doped 32-atom super-cell of AlN was optimized with first principle density functional theory based on full potential linearized augumented plane wave method. Electronic structures,magnetic and optical properties were calculated and discussed in detail. It shows that Ag doping makes Ag4 d electrons hybrid with its nearest neighbor N2 p electrons,which introduces impurity bands to form acceptor energy level and realizes p-type doping. The system enhances its conductivity and shows metallic and weak magnetism. Its net magnetic moment is 1. 38 μв. Mulliken charge population of N-Ag bonds through Ag doping is small and bonds show strong ionic bonding properties. Imaginary part of dielectric function and optical absorption spectrum of the doping system show a new peak in low energy region. Complex refractive index function changes in low energy region. And absorption edge extends to low energy. Doping system enhances long-wave absorption and energy loss decreases obviously.