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Controlling Photoluminescence Enhancement and Energy Transfer in WS 2 :hBN:WS 2 Vertical Stacks by Precise Interlayer Distances
Author(s) -
Xu Wenshuo,
Kozawa Daichi,
Zhou Yingqiu,
Wang Yizhi,
Sheng Yuewen,
Jiang Tian,
Strano Michael S.,
Warner Jamie H.
Publication year - 2020
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201905985
Subject(s) - photoluminescence , materials science , heterojunction , monolayer , photonics , doping , optoelectronics , chemical vapor deposition , stack (abstract data type) , spectroscopy , quantum yield , nanotechnology , optics , physics , computer science , programming language , quantum mechanics , fluorescence
2D semiconducting transition metal dichalcogenides (TMDs) are endowed with fascinating optical properties especially in their monolayer limit. Insulating hBN films possessing customizable thickness can act as a separation barrier to dictate the interactions between TMDs. In this work, vertical layered heterostructures (VLHs) of WS 2 :hBN:WS 2 are fabricated utilizing chemical vapor deposition (CVD)‐grown materials, and the optical performance is evaluated through photoluminescence (PL) spectroscopy. Apart from the prohibited indirect optical transition due to the insertion of hBN spacers, the variation in the doping level of WS 2 drives energy transfer to arise from the layer with lower quantum efficiency to the other layer with higher quantum efficiency, whereby the total PL yield of the heterosystem is increased and the stack exhibits a higher PL intensity compared to the sum of those in the two WS 2 constituents. Such doping effects originate from the interfaces that WS 2 monolayers reside on and interact with. The electron density in the WS 2 is also controlled and subsequent modulation of PL in the heterostructure is demonstrated by applying back‐gated voltages. Other influential factors include the strain in WS 2 and temperature. Being able to tune the energy transfer in the VLHs may expand the development of photonic applications in 2D systems.