单层SnS的光电效应及应变工程的第一性原理研究  

First-Principles Study on Photogalvanic Effect and Strain Engineering of Monolayer SnS

作　　者：徐中辉[1,2] 许晟源 刘川川 刘国港 XU Zhonghui;XU Shengyuan;LIU Chuanchuan;LIU Guogang(School of Information Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China;Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology,Shanghai 200092,China;MOE Key Laboratory of Microstructured Materials,School of Physics Science and Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]江西理工大学信息工程学院,赣州341000 [2]上海市特种人工微结构材料与技术重点实验室,上海200092 [3]同济大学物理科学与工程学院,微结构材料教育部重点实验室,上海200092

出　　处：《人工晶体学报》2024年第4期676-683,共8页Journal of Synthetic Crystals

基　　金：国家自然科学基金(12364024,11864014);江西省自然科学基金(20224BAB201023);上海市特种人工微结构材料与技术重点实验室开放项目(ammt2021A-3);江西省研究生创新专项基金(203200800337)。

摘　　要：光电探测器在工业制造和军事国防等各领域用途广泛。近年来,研究者在寻找一种兼具极化灵敏度高与光响应强的特点的光电探测器。在可见光范围内,SnS是一种制作具有各向异性光电探测器的半导体材料。本文基于第一性原理,采用非平衡态格林函数(NEGF)与密度泛函理论(DFT)结合的方法对单层SnS两个器件方向(Armchair和Zigzag)的光电性质进行理论计算。研究发现,在零偏压下,两个方向的光电流数值均较小,通过加偏压的方法可以获得稳定的光电流。计算了小偏压0.1~1.0 V(间隔0.1 V)、线性偏振光照射下最大光响应随光子能量的变化,发现单层SnS在光子能量为2.4与3.2 V时最大光响应数值较大且十分稳定,并结合能带图和态密度图分析了光响应产生的微观机制。本文通过计算消光比,发现单层SnS具有极强的偏振灵敏度。最后,通过施加双轴应变的方法,器件的不对称性显著增加,极大增强器件在零偏压下的光电流,其中压缩应力数值为-6%时对光电流的提升十分明显。希望以上结果能为单层SnS设计用于光电探测器提供理论参考。Photodetectors are widely used in various fields,such as industrial manufacturing and military defense.Researchers have recently sought a photodetector that combines high polarization sensitivity and a robust optical response.As an anisotropic semiconductor material,SnS holds potential for photodetection across the visible light spectrum.This study employs first-principles density functional theory(DFT)along with the non-equilibrium Green's function(NEGF)method to theoretically investigate the optoelectronic properties of the SnS monolayer in two device orientations:Armchair and Zigzag.It is found that the maximum photocurrent values between the two orientations are small at zero bias voltage,and stable photocurrent can be obtained by adding bias voltage.We examine the maximum photocurrent variation under linearly polarized light irradiation within a small bias voltage range(0.1 to 1.0 V),found for the maximum photoresponse of monolayer SnS to be large and stable at photon energy of 2.4 and 3.2 eV,and analyze the underlying mechanism of photoresponse,employing energy band and density of state diagrams.Additionally,we have calculated the extinction ratio of the SnS monolayer,confirming its strong polarization sensitivity.Finally,by subjecting the device to biaxial strain,we significantly speculate to enhance its asymmetry,leading to a substantial increase in photocurrent at zero bias.A compressive strain of-6%notably increases the photocurrent.These findings offer valuable theoretical insights for the design of SnS monolayers as photodetectors.

关 键 词：单层SnS 光电探测器 第一性原理 最大光响应 偏振灵敏度 应变工程 

分 类 号：O472[理学—半导体物理] O469[理学—物理]