单层MoS_2的电子结构及光学性质

Electronic Structure and Optical Properties of Monolayer MoS_2

基于密度泛函理论框架下的第一性原理,采用平面波赝势方法计算和分析了单层MoS2的电子结构及其光学性质,得到了单层MoS2的能带结构、电子态密度、光吸收谱、反射谱、能量损失谱、光学常数谱和介电函数谱。计算结果显示:单层MoS2具有直接带隙能带结构,禁带宽度为1.726 eV;同时发现,单层MoS2对可见到紫外区域的光子具有很强的吸收,最大吸收系数为1.98 105cm-1。分析表明,单层MoS2适合被用于制作微电子和光电子器件,尤其是在紫外探测器应用方面具有潜在的应用前景。

In order to further understand the electronic structure and the optical properties of MoS2, using the first-principle and based on density functional theory, the electronic structure and the optical properties of single-layer MoS2 were calculated and analyzed by the plane wave pseudo-potential method. Band structure, density of states, and optical absorption, reflection, energy loss, optics constants and dielectric function spectra of monolayer MoS2 were obtained. The calculation results show that the single-layer MoS2 has a direct band structure, the band gap width is 1.726 eV. It is found that MoS2 monolayer has a strong absorption of photons from visible light to the ultraviolet region, the maximum absorption coefficient of 1.98x10^5 cm^-1. The analysis indicates that the single-layer MoS2 is suitable for the fabrication of microelectronic and optoelectronic devices, especially in the ultraviolet （UV） detector applications.