Modulation of carrier lifetime in MoS2 monolayer by uniaxial strain  

作　　者：Hao Hong Yang Cheng Chunchun Wu Chen Huang Can Liu Wentao Yu Xu Zhou Chaojie Ma Jinhuan Wang Zhihong Zhang Yun Zhao Jie Xiong Kaihui Liu 洪浩;程阳;吴春春;黄琛;刘灿;于文韬;周旭;马超杰;王金焕;张智宏;赵芸;熊杰;刘开辉(State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics,Collaborative Innovation Center of Quantum Matter,School of Physics,Peking University,Beijing 100871,China;State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054,China;School of Chemistry and Chemical Engineering,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics,Collaborative Innovation Center of Quantum Matter,School of Physics,Peking University,Beijing 100871,China [2]State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054,China [3]School of Chemistry and Chemical Engineering,Beijing Institute of Technology,Beijing 100081,China

出　　处：《Chinese Physics B》2020年第7期182-187,共6页中国物理B（英文版）

基　　金：Project supported by the Natural Science Foundation of Beijing,China(Grant No.JQ19004);the Excellent Talents Training Support Fund of Beijing,China(Grant No.2017000026833ZK11);the National Natural Science Foundation of China(Grant Nos.51991340 and 51991342);the National Key Research and Development Program of China(Grant Nos.2016YFA0300903 and 2016YFA0300804);the Key Research and Development Program of Guangdong Province,China(Grant Nos.2019B010931001,2020B010189001,2018B010109009,and 2018B030327001);the Science Fund from the Municipal Science&Technology Commission of Beijing,China(Grant No.Z191100007219005);the Graphene Innovation Program of Beijing,China(Grant No.Z181100004818003);the Fund from the Bureau of Industry and Information Technology of Shenzhen City,China(Graphene platform 201901161512);the Innovative and Entrepreneurial Research Team Program of Guangdong Province,China(Grant No.2016ZT06D348);the Fund from the Science,Technology,and Innovation Commission of Shenzhen Municipality,China(Grant No.KYTDPT20181011104202253).

摘　　要：Carrier lifetime is one of the most fundamental physical parameters that characterizes the average time of carrier recombination in any material.The control of carrier lifetime is the key to optimizing the device function by tuning the electro-optical conversion quantum yield,carrier diffusion length,carrier collection process,etc.Till now,the prevailing modulation methods are mainly by defect engineering and temperature control,which have limitations in the modulation direction and amplitude of the carrier lifetime.Here,we report an effective modulation on the ultrafast dynamics of photoexcited carriers in two-dimensional(2D)MoS2 monolayer by uniaxial tensile strain.The combination of optical ultrafast pump-probe technique and time-resolved photoluminescence(PL)spectroscopy reveals that the carrier dynamics through Auger scattering,carrier-phonon scattering,and radiative recombination keep immune to the strain.But strikingly,the uniaxial tensile strain weakens the trapping of photoexcited carriers by defects and therefore prolongs the corresponding carrier lifetime up to 440%per percent applied strain.Our results open a new avenue to enlarge the carrier lifetime of 2D MoS2,which will facilitate its applications in high-efficient optoelectronic and photovoltaic devices.

关 键 词：two-dimensional materials carrier dynamics STRAIN trap states 

分 类 号：TB34[一般工业技术—材料科学与工程]