Ultrafast investigation of room temperature valley polarization in"optical bilayer"WS2

ZHAO LeYi ¹WANG Hai ²LIU TianYu ²LI FangFei ³ZHOU Qiang ³WANG HaiYu²

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作者信息

1. Synergetic Extreme Condition High-Pressure Science Center,State Key Laboratory of Superhard Materials,College of Physics,Jilin University Changchun 130012,China;State Key Laboratory of Integrated Optoelectronics,College of Electronic Science and Engineering,Jilin University,Changchun 130012,China
2. State Key Laboratory of Integrated Optoelectronics,College of Electronic Science and Engineering,Jilin University,Changchun 130012,China
3. Synergetic Extreme Condition High-Pressure Science Center,State Key Laboratory of Superhard Materials,College of Physics,Jilin University Changchun 130012,China
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Abstract

Monolayer transition metal dichalcogenides(TMDCs)have become a promising platform in valleytronics due to possessing the regulatable valley degrees of freedom.While,as a result of the rapid intervalley scattering,it is difficult to measure the PL valley polarization of monolayer TMDCs at room temperature,which limits their application in valleytronics devices.Here,we report a room temperature photoluminescence(PL)valley polarization up to 3.73％in an"optical bilayer"WS2 formed by transferring monolayer WS2 onto flat Ag film.Furthermore,in the transient absorption(TA)measurements,a remarkably long valley depolarization lifetime is found.Thus,we demonstrate the valley properties of such"optical bilayer"WS2 resemble actual bilayer WS2,in which the robust valley polarization can be attributed to the phonons depletion effect and the blocked interlayer hopping processes.These peculiar valley features in"optical bilayer"WS2 provide a particularly simple method to enhance valley control at room temperature.

Key words

valleytronics/optical bilayer/transient absorption/tungsten disulfide

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基金项目

National Natural Science Foundation of China(21903035)

National Natural Science Foundation of China(22073037)

National Natural Science Foundation of China(21773087)

National Natural Science Foundation of China(12074141)

National Natural Science Foundation of China(12274168)

Jilin Provincial Science and Technology Development Project(20210509038RQ)

Jilin Provincial Science and Technology Development Project(20230101059JC)

出版年

2024

中国科学:技术科学(英文版)

中国科学院

中国科学:技术科学(英文版)

CSTPCDEI

影响因子：1.056

ISSN：1674-7321

参考文献量42

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