Tightly Bound Excitons in Monolayer WSe2

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Issue Date
2014-07-11Author
He, Keliang
Kumar, Nardeep
Zhao, Liang
Wang, Zefang
Mak, Kin Fai
Zhao, Hui
Shan, Jie
Publisher
American Physical Society
Type
Article
Article Version
Scholarly/refereed, publisher version
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Show full item recordAbstract
Exciton binding energy and excited states in monolayers of tungsten diselenide (WSe2) are investigated using the combined linear absorption and two-photon photoluminescence excitation spectroscopy. The exciton binding energy is determined to be 0.37 eV, which is about an order of magnitude larger than that in III–V semiconductor quantum wells and renders the exciton excited states observable even at room temperature. The exciton excitation spectrum with both experimentally determined one- and two-photon active states is distinct from the simple two-dimensional (2D) hydrogenic model. This result reveals significantly reduced and nonlocal dielectric screening of Coulomb interactions in 2D semiconductors. The observed large exciton binding energy will also have a significant impact on next-generation photonics and optoelectronics applications based on 2D atomic crystals.
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This is the published version. Copyright © 2014 American Physical Society
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Citation
He, Keliang, Nardeep Kumar, Liang Zhao, Zefang Wang, Kin Fai Mak, Hui Zhao, and Jie Shan. "Tightly Bound Excitons in Monolayer WSe 2." Phys. Rev. Lett. Physical Review Letters 113.2 (2014). http://dx.doi.org/10.1103/PhysRevLett.113.026803
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