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Monolayer transition metal dichalcogenides (TMDs) show significant promise as excellent options for optoelectronic applications due to their direct band gap and exceptional quantum yield. However, light-emitting devices based on TMD channels have shown low external quantum efficiencies due to the high contact barrier hindering carrier injection, the inevitable doping of the TMDs, and the non-radiative recombination of charged excitons, thus collectively imposing restrictions on their practical applications. Here, we demonstrate electrically confined electroluminescence of neutral excitons in WSe2 light-emitting transistors (LETs) based on the van der Waals (vdW) heterostructure. The WSe2 channel is doped locally to simultaneously inject electrons and holes to the one-dimensional (1D) pn junction region by a local graphene gate. At balanced concentrations of injected electrons and holes, the WSe2 LETs exhibited strong electroluminescence with a high external quantum efficiency (EQE) of ~8.2% at room temperature. Our calculations show that the neutral excitons are confined electrically in the 1D region of WSe2, and charged excitons are expelled toward corresponding doped regions with low potentials by charge interaction and the in-plane electric field along the edge of the graphene gate. Our work shows a potential way to electrically confine neutral excitons in the 2D light-emitting transistors and modulate the recombination of exciton complexes for excitonic devices.

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• In Copyright
  

  This is the peer reviewed version of the following article: J.-C. Shin, J. H. Jeong, J. Kwon, Y. H. Kim, B. Kim, S.-J. Woo, K. Y. Woo, M. Cho, K. Watanabe, T. Taniguchi, Y. D. Kim, Y.-H. Cho, T.-W. Lee, J. Hone, C.-H. Lee, G.-H. Lee, Electrically Confined Electroluminescence of Neutral Excitons in WSe2 Light-Emitting Transistors. Adv. Mater. 2024, 36, 2310498, which has been published in final form at https://doi.org/10.1002/adma.202310498. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

Keyword: Transition metal dichalcogenides, light-emitting devices, quantum efficiency

Date published: 2024-01-08

Publisher: Wiley

Journal:

• Advanced Materials (ISSN: 15214095) vol. 36 issue. 14 2310498

Funding:

• National Research Foundation of Korea
• Seoul National University
• National Center for Inter-University Research Facilities, Seoul National University
• LG Display 2021R1A2C3014316
• Institute of Engineering Research, Seoul National University

Manuscript type: Author's version (Accepted manuscript)

MDR DOI:

First published URL: https://doi.org/10.1002/adma.202310498

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Updated at: 2025-07-30 16:30:26 +0900

Published on MDR: 2025-07-30 16:18:00 +0900