Evaluating the quantum confinement effects modulating exciton and electronic band structures of two-dimensional layered MoSSe films and their photodetection potentials  

量子约束效应调制的二维层状MoSSe薄膜激子和电子能带结构及其光探测潜力

作　　者：Yifan Ding Xudan Zhu Hongyu Tang Weiming Liu Shuwen Shen Jiajie Fan Yi Luo Yuxiang Zheng Chunxiao Cong Siyuan Luo Rongjun Zhang 丁依凡;朱绪丹;唐红雨;刘未名;申淑雯;樊嘉杰;罗毅;郑玉祥;丛春晓;罗思源;张荣君(Department of Optical Science and Engineering,Key Laboratory of Micro and Nano Photonic Structures(MOE),Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing,Fudan University,Shanghai 200433,China;Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and Proception,Institute of Optoelectronics,Fudan University,Shanghai 200433,China;Academy for Engineering and Technology,Fudan University,Shanghai 200433,China;School of Information Science and Engineering,Fudan University,Shanghai 200433,China;Microsystem and Terahertz Research Center,Chengdu 610200,China;Shanghai Institute of Intelligent Electronics&Systems,Shanghai 200433,China)

机构地区：[1]Department of Optical Science and Engineering,Key Laboratory of Micro and Nano Photonic Structures(MOE),Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing,Fudan University,Shanghai 200433,China [2]Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and Proception,Institute of Optoelectronics,Fudan University,Shanghai 200433,China [3]Academy for Engineering and Technology,Fudan University,Shanghai 200433,China [4]School of Information Science and Engineering,Fudan University,Shanghai 200433,China [5]Microsystem and Terahertz Research Center,Chengdu 610200,China [6]Shanghai Institute of Intelligent Electronics&Systems,Shanghai 200433,China

出　　处：《Science China Materials》2024年第10期3087-3095,共9页中国科学（材料科学）（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(U2230108,62275053);the National Key R&D Program of China(2021YFB2012601).

摘　　要：Emerging two-dimensional ternary transition metal dichalcogenide alloys have attracted much attention for their unique optical and optoelectronic properties,making them ideal candidates for optoelectronic applications.However,a comprehensive understanding of their quantum confinement effects and photoelectronic response characteristics remains crucial for device optimization and performance enhancement.In this study,we employed various spectroscopic techniques to investigate the optical properties and electronic band structures of molybdenum sulfide selenide(MoSSe)films with different layer numbers(4–11 layers).Our results revealed the splitting of Raman modes and shifting of phonon vibrational frequencies with increasing thickness,suggesting that MoSSe has strong interactions within the lattice.The A1g and E2g 1 modes were mainly shifted by internal strain and dielectric screening effect versus thickness,respectively.The redshift phenomenon of A and B excitons with increasing thickness was attributed to the leading effect of quantum confinement on exciton properties and optical band gaps.We observed a strong decrease in the direct bandgap spectral weight in photoluminescence(PL)when the layer number increased from 4 to 5.In addition,we have fabricated MoSSe photodetectors that exhibit a broadband response in the visible wavelength band of 350–800 nm.Furthermore,the observed enhancement in photocurrent and responsivity with increasing film thickness underscored the potential of MoSSebased devices for practical optoelectronic applications.This research contributes to advancing our fundamental understanding of MoSSe materials and paves the way for the design and development of high-performance optoelectronic devices.三元过渡金属硫族化合物(TMDs)合金因其独特的光学和光电性能而备受关注,是光电子应用的理想候选者.目前对其量子约束效应和光电子响应特性还未全面了解.本项研究利用多种光谱测试分析方法来研究不同层数(4~11层)的MoSSe薄膜的光学性质和电子能带结构.研究结果揭示了拉曼模式的分裂及声子振动频率随着厚度的增加的移动,表明MoSSe在晶格内具有强烈的相互作用.A、B激子随层数增加的红移现象,证明了量子约束对激子性质和光学带隙的主导作用.制备的MoSSe光电探测器展现出了在350–800 nm范围内的宽光谱探测能力.其光电流和响应度随着薄膜厚度的增加而增强,极大凸显了基于MoSSe薄膜的光电探测器件在实际光电应用中的潜力.

关 键 词：MoSSe alloy quantum confinement effects EXCITON electronic band structure PHOTODETECTION 

分 类 号：TB383.2[一般工业技术—材料科学与工程] TN15[电子电信—物理电子学]