Electrically Confined Electroluminescence of Neutral Excitons in WSe2 Light-Emitting Transistors

June Chul Shin, Jae Hwan Jeong, Junyoung Kwon, Yeon Ho Kim, Bumho Kim, Seung Je Woo, Kie Young Woo, Minhyun Cho, Kenji Watanabe, Takashi Taniguchi, Young Duck Kim, Yong Hoon Cho, Tae Woo Lee, James Hone, Chul Ho Lee, Gwan Hyoung Lee

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Monolayer transition metal dichalcogenides (TMDs) have drawn significant attention for their potential in optoelectronic applications due to their direct band gap and exceptional quantum yield. However, TMD-based light-emitting devices have shown low external quantum efficiencies as imbalanced free carrier injection often leads to the formation of non-radiative charged excitons, limiting practical applications. Here, electrically confined electroluminescence (EL) of neutral excitons in tungsten diselenide (WSe2) light-emitting transistors (LETs) based on the van der Waals heterostructure is demonstrated. The WSe2 channel is locally doped to simultaneously inject electrons and holes to the 1D region by a local graphene gate. At balanced concentrations of injected electrons and holes, the WSe2 LETs exhibit strong EL with a high external quantum efficiency (EQE) of ≈8.2 % at room temperature. These experimental and theoretical results consistently show that the enhanced EQE could be attributed to dominant exciton emission confined at the 1D region while expelling charged excitons from the active area by precise control of external electric fields. This work shows a promising approach to enhancing the EQE of 2D light-emitting transistors and modulating the recombination of exciton complexes for excitonic devices.

Original languageEnglish
Article number2310498
JournalAdvanced Materials
Volume36
Issue number14
DOIs
Publication statusPublished - 2024 Apr 4
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2024 Wiley-VCH GmbH.

Keywords

  • electrical confinement
  • electroluminescence
  • light-emitting transistor
  • neutral exciton
  • van der Waals heterostructure

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering

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