悬浮双层MoSe_(2)激子的机械和电学调控  

Mechanical and Electrical Control of Excitons in Suspended Bilayer MoSe_(2)

作　　者：高静文 熊志仁 李小茜 张桐耀 GAO Jingwen;XIONG Zhiren;LI Xiaoxi;ZHANG Tongyao(State Key Laboratory of Quantum Optics and Optical Quantum Devices,Institute of Optoelectronics,Shanxi University,Taiyuan 030006,China;Extreme Optics Collaborative Innovation Center,Taiyuan 030006,China)

机构地区：[1]量子光学与光量子器件国家重点实验室,山西大学光电研究所,山西太原030006 [2]极端光学协同创作中心,山西太原030006

出　　处：《山西大学学报（自然科学版）》2024年第4期809-814,共6页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(U21A6004,12004389,62274180,12204287)。

摘　　要：二维过渡金属硫族化合物(Transition metal dichalcogenides,TMDs)如二硒化钼MoSe_(2)等具有优异的电学、光学和机械性能,是研究纳米光机电耦合系统(Nano-opto-electro-mechanical coupling systems,NOEMS)的理想材料。由于二维激子的高效发光,基于通过NOEMS系统可对TMDs激子的吸收和发射特性进行动态调制。本文分别加工了悬浮结构的双层和单层MoSe_(2)纳米光机电器件,通过低温下机械共振测量发现,双层MoSe_(2)的机械共振线宽明显宽于单层MoSe_(2),进而机械品质因子更小,且随栅压增大共振线宽变宽,品质因子随之减小;光致发光(Photoluminescence,PL)光谱表明,尽管悬浮区域双层MoSe_(2)层间激子的PL发射远低于单层MoSe_(2)层内激子的PL发射,但双层MoSe_(2)悬浮区域的层间激子PL强度高于硼氮衬底,并且观测到悬浮双层样品有衬底时淬灭的层内激子,且层内激子不受电压掺杂和应力的调控;此外,根据栅极电压调控的结果,我们发现在该悬浮系统中静电感应诱导的应变调控强于电压掺杂调控。Two-dimensional transition metal chalcogenides(TMDs),such as molybdenum selenide(MoSe_(2)),have excellent electrical,optical and mechanical properties,and are ideal materials for the study of nano-opto-electro-mechanical coupling systems(NOEMS).The absorption and emission characteristics of TMDs excitons can be dynamically modulated based on the NOEMS system.In this paper,bilayer and monolayer MoSe_(2)nano-opto-electro-mechanical devices with suspended structure are fabricated respectively.By measuring mechanical resonance at a cryogenic temperature of 10 K,it is found that the mechanical resonance linewidth of bilayer MoSe_(2)is significantly wider,hence lower mechanical quality factor,than that of monolayer MoSe_(2).PL photoluminescence of the inter-layer exciton in the suspended bilayer MoSe_(2)exhibits enhanced intensity than bilayers supported by a hexagonal boron nitride(h-BN)substrate,yet is far lower than the that of intra-layer exciton in the monolayer case.The intra-layer excitons,seen in the suspended bilayer MoSe_(2),however,are quenched in the h-BN-supported region.In addition,by applying a gate voltage,we find that the electrostatically-induced strain plays a more pronounced role than that of the electric doping in our suspended devices.

关 键 词：双层MoSe_(2) 激子调控 机械共振 光致发光光谱 

分 类 号：O436[机械工程—光学工程]