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Excitonic Landscape and Phonon-Mediated Recombination in Moiré-Engineered Twisted WSe2 Bilayers
Memansa Thapa1, Aksa Thomas1, Jayalekshmi U J2,3
1School of Physical Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh 175005, India.
Nano Letters
|July 13, 2026
Summary
Twist-angle engineering in tungsten diselenide (WSe2) bilayers creates moiré superlattices. This tuning enhances interlayer excitonic emission and stabilizes excitons by controlling carrier distribution, opening new avenues in quantum phenomena research.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Optics
Background:
- Two-dimensional (2D) van der Waals (vdW) heterostructures offer tunable optoelectronic properties via twist-angle engineering.
- Moiré superlattices in twisted 2D materials create unique quantum interaction environments.
Purpose of the Study:
- To investigate light emission from moiré superlattices in twisted tungsten diselenide (WSe2) bilayers.
- To understand the role of moiré potential in modulating excitonic properties and recombination pathways.
Main Methods:
- Fabrication of twisted WSe2/WSe2 heterostructures encapsulated in hexagonal boron nitride (hBN).
- Low-temperature photoluminescence (PL) spectroscopy to analyze light emission characteristics.
- Analysis of moiré-potential effects on carrier distribution and exciton dynamics.
Main Results:
- Observed strong interlayer excitonic emission and phonon-assisted recombinations attributed to the moiré potential.
- Demonstrated suppression of defect-bound exciton emission with increasing twist angle.
- Showcased moiré potential's role in redistributing carriers to indirect valleys, enhancing recombination efficiency and stabilizing interlayer excitons.
Conclusions:
- Twist-angle control in WSe2/WSe2 heterostructures enables engineering of moiré superlattices for enhanced light emission.
- The moiré potential significantly influences exciton behavior, favoring interlayer excitons over defect-bound ones.
- This work provides a new pathway for exploring exciton-phonon interactions and quantum phenomena in 2D materials.
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