外电场作用下InP电子结构与光学性质的计算

Calculation of Electronic Structure and Optical Properties of InP Under External Electric Field

摘要:

磷化铟(InP)已成为光电器件和微电子器件不可或缺的重要半导体材料。采用基于密度泛函理论框架下的第一性原理平面波赝势方法,计算了不同外电场作用下InP超胞的电子结构和光学性质。计算结果表明:未加电场时InP的能隙值为0.876eV,随着z轴方向的外电场增大,该值逐渐减小,当电场强度达到1.0×10⁸V/cm时,InP的禁带宽度几乎为0。InP导带区域的总态密度随着外电场增大逐渐向费米面偏移,态密度跨度变小,而价带与导带的情况恰恰相反。外电场对介电函数虚部的影响主要体现在低能量区域(0~7eV),而在较高能量区域内可忽略不计。外电场对InP吸收系数的影响主要集中在近红外波段。

Abstract:

Indium phosphide (InP) has become an indispensable semiconductor material for optoelectronic and microelectronic devices. In this paper, the band structure, state density and optical properties of InP under different electric fields were calculated by the first-principles plane wave pseudopotential method based on density functional theory framework. Calculation results show that the energy gap of InP is 0.876eV when no electric field is applied, and it becomes smaller with the increasing electric field strength in the z-axis, and when the electric field strength reaches 1.0×10⁸V/cm, the band gap of InP is almost 0. The total density of states of InP conduction band region gradually shifts to Fermi surface and the span gradually decrease with the increasing electric field strength, while for the valence band, it is just the opposite situation. The Influence of external electric fields on imaginary part of the dielectric function is mainly in low energy range (0~7eV) and is negligible in higher energy range. The influence of external electric field on absorption coefficient of InP is mainly concentrated in the near-infrared band.