Te掺杂单层MoS2的电子结构与光电性质

摘要

采用基于密度泛函理论的第一性原理计算，研究了Te掺杂对单层MoS2能带结构、电子态密度和光电性质的影响。结果表明，本征单层MoS2属于直接带隙半导体材料，其禁带宽度为1.64 eV。本征单层MoS2的价带顶主要由S-3p态电子和Mo-4d态电子构成，而其导带底则主要由Mo-4d态电子和S-3p态电子共同决定；Te掺杂单层MoS2为间接带隙半导体材料，其禁带宽度为1.47 eV。同时通过Te掺杂，使单层MoS2的静态介电常数增大，禁带宽度变窄，吸收光谱产生红移，研究结果为单层MoS2在光电器件方面的应用提供了理论基础。%We have performed first-principles calculations based the framework of density-functional theory to determine the effects of Te doping on the band structure, density of state and photoelectric properties of single-layer MoS2 . The calculated results indicate that the direct band-gap of pure sin-gle-layer MoS2 is 1. 64 eV. The top of valence band is fundamentally determined by the S-3p and Mo-4d states, and the bottom of conduction band is occupied by the Mo-4d and S-3p states in the pure single-layer MoS2 . Meanwhile, the indirect band-gap of Te-doped single-layer MoS2 is 1. 47 eV, while the band gap of Te-doped single-layer MoS2 has decreased and the optical absorption has shown a red-shifted observably as compared with the pure single-layer MoS2 , which provides impor-tant theoretical guidance for the applications of single-layer MoS2 in optical detectors.