单层SnS薄膜的光吸收特性及应变调控:基于第一性原理计算的GW-BSE方法  

Strain-tunable optical properties of the monolayer SnS:A first-principles GW-BSE study

作　　者：李文涛 LI Wen-tao(School of Arts and Sciences, Shaanxi University of Science & Technology, Xi′an 710021, China)

机构地区：[1]陕西科技大学文理学院,陕西西安710021

出　　处：《陕西科技大学学报》2021年第3期172-176,186,共6页Journal of Shaanxi University of Science & Technology

基　　金：陕西科技大学博士科研启动基金项目(2016BJ-77)。

摘　　要：单层SnS薄膜作为一种典型的二维材料,由于其电子结构中存在能隙,因此在光电和催化等领域拥有广阔的应用前景.基于第一性原理计算,采用多体格林函数理论的GW近似方法,研究了单层SnS薄膜经过准粒子修正后的能带特征和带隙宽度,并利用描述电子和空穴对的Bethe-Salpeter方程(BSE)给出了这类二维薄膜的介电函数和光吸收特性.以此为基础,还系统研究了施加不同应变对单层SnS薄膜的电子结构和光吸收特性的影响和调控,研究结果表明通过在二维面内施加不同应变,能够实现对单层SnS薄膜的带隙宽度和带隙类型(直接和间接带隙)的有效调控,进而影响其光吸收特性.研究结果可以为将来针对这类二维材料进一步开展人工低维器件的制备以及拓展其在光电等领域的应用提供理论基础.The monolayer SnS,a potential two-dimensional material,is a semiconductor with an indirect band gap.Recently,it has attracted much attention because of its extraordinary physical properties and prospective applications in optoelectronic devices.In the present work,we systematically studied the electronic properties of the two-dimensional SnS under both uniaxial and biaxial strains based on the first-principles GW methods.Combined with the Bethe-Salpeter equation,the optical properties of the monolayer SnS have also been investigated.Our results indicated that the electronic band structure of monolayer SnS can be effectively changed by the applied strain,and a transition from the indirect band gap to direct band gap was observed in the monolayer under the uniaxial strain.The calculated optical spectra of the monolayer SnS indicated a strong anisotropy under the uniaxial strain.According to these results,the monolayer SnS presented abundant opportunities for creating novel high performance nanoelectronic and optoelectronic devices in the future.

关 键 词：SNS 二维材料 光吸收 GW方法 BETHE-SALPETER方程 

分 类 号：O469[理学—凝聚态物理]