Microsecond Valley Lifetime of Defect-Bound Excitons in Monolayer WSe^sub 2

In atomically thin two-dimensional semiconductors such as transition metal dichalcogenides (TMDs), controlling the density and type of defects promises to be an effective approach for engineering light-matter interactions. We demonstrate that electron-beam irradiation is a simple tool for selectivel...

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Bibliographic Details
Published in:Physical review letters 2018-08, Vol.121 (5), p.057403
Main Authors: Moody, Galan, Tran, Kha, Lu, Xiaobo, Autry, Travis, Fraser, James M, Mirin, Richard P, Yang, Li, Li, Xiaoqin, Silverman, Kevin L
Format: Article
Language:English
Subjects:
Crystal defects
Crystal lattices
Defects
Electron beams
Electron irradiation
Excitons
First principles
Lattice vacancies
Monolayers
Optical properties
Photonics
Quantum optics
Transition metal compounds
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Summary:In atomically thin two-dimensional semiconductors such as transition metal dichalcogenides (TMDs), controlling the density and type of defects promises to be an effective approach for engineering light-matter interactions. We demonstrate that electron-beam irradiation is a simple tool for selectively introducing defect-bound exciton states associated with chalcogen vacancies in TMDs. Our first-principles calculations and time-resolved spectroscopy measurements of monolayer WSe2 reveal that these defect-bound excitons exhibit exceptional optical properties including a recombination lifetime approaching 200 ns and a valley lifetime longer than 1 μs . The ability to engineer the crystal lattice through electron irradiation provides a new approach for tailoring the optical response of TMDs for photonics, quantum optics, and valleytronics applications.
ISSN:0031-9007
1079-7114