Tc-P共掺杂单层MoS_2光电特性的第一性原理计算

First-principles Calculation of Optical-Electrical Properties of Single-layer MoS_2 with Tc-P Doping

采用第一性原理的贋势平面波方法,对比研究了未掺杂和掺杂过渡金属Tc、非金属P及Tc-P共掺杂的单层MoS2的电子结构和光学性质。计算结果表明:掺杂改变了费米面附近的电子结构,使得导带向低能方向偏移,并且带隙由K点转化为Γ点,形成Γ点的直接带隙半导体。掺杂P使带隙值变小,形成p型半导体;掺杂Tc使带隙变宽,形成n型半导体;Tc-P共掺杂,由于p型和n型半导体相互调制,使得单层MoS2转变为性能更优的本征半导体;掺杂使光跃迁强度减小,且向低能方向偏移。

The electronic structures and optical properties of single-layer MoS2 with Tc doping, P doping and Tc-P doping were calculated by density functional theory （DFT） of the first-principles pseudo potential wave method. The calculated results show that element doping can change the electron structures of single-layer MoS2 near the Fermi surface and shift the conduction bands to the direction of low energy. Single-layer MoS2 is a direct-band-gap semiconductor with the band gap from K-point into/＇-point, respectively. The single-layer MoS2 is converted to a p-type semiconductor and the band gap value is reduced by P-doping. The singlelayer MoS2 is converted to a n-type semiconductor and the band gap value is increased by Tc- doping. The sigle-layer MoS2 of Tc-P codoping is modulated to the intrinsic semiconductor of better performance for a n-type and a p-type semiconductor modulation with each other. The transition strength is reduced and moved to the direction of low energy by doping.