Room-Temperature, Strong Emission of Momentum-Forbidden Interlayer Excitons in Nanocavity-Coupled Twisted van der Waals Heterostructures

Bin Feng, Shixuan Zhao, Ilya Razdolski, Feihong Liu, Zhiwei Peng, Yaorong Wang, Zhedong Zhang, Zhenhua Ni, Jianbin Xu, Dangyuan Lei*

*Corresponding author for this work

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

1 Citation (Scopus)
7 Downloads (CityUHK Scholars)

Abstract

The emission efficiency of interlayer excitons (IEs) in twisted 2D heterostructures has long suffered from momentum mismatch, limiting their applications in ultracompact excitonic devices. Here, we report strong room-temperature emission of momentum-forbidden IE in 30°-twisted MoS2/WS2 heterobilayers. Utilizing a plasmonic nanocavity, the Purcell effect boosts the IE emission intensity in the cavity by over 2 orders of magnitude. We further study the interplay of this Purcell enhancement and phonon assistance in 30°- and 0°-twisted heterostructures. Temperature-dependent and time-resolved spectroscopy reveal that the IE enhancement in 30°-twisted cases involves competition between IEs and intralayer excitonic emission, which is remarkably distinct from the 0°-twisted cases. We propose a comprehensive exciton decay model capturing the features of the phonon-assisted momentum compensation and the Purcell enhancement of the IE emission, showing consistency with the experimental measurements. Our results enrich the understanding of the nanocavity-assisted light-matter interaction for momentum-indirect excitonic transitions. © 2025 American Chemical Society.
Original languageEnglish
Pages (from-to)1609–1616
JournalNano Letters
Volume25
Issue number4
Online published8 Jan 2025
DOIs
Publication statusPublished - 29 Jan 2025

Funding

We acknowledge the financial support from the Research Grants Council of Hong Kong through a General Research Fund Grant (11309623) and an Area of Excellence Grant (AoE/P-701/20). B.F. appreciates Tsz Wing Lo for his fruitful discussions.

Research Keywords

  • heterostructure
  • interlayer exciton
  • momentum mismatch
  • Purcell effect
  • twist angle

Publisher's Copyright Statement

  • This full text is made available under CC-BY 4.0. https://creativecommons.org/licenses/by/4.0/

Fingerprint

Dive into the research topics of 'Room-Temperature, Strong Emission of Momentum-Forbidden Interlayer Excitons in Nanocavity-Coupled Twisted van der Waals Heterostructures'. Together they form a unique fingerprint.

Cite this