Twist Angle-Dependent Exciton Mobility in WS<sub>2</sub> Bilayers
Bilayer WS<sub>2</sub> shows exceptional promise for excitonic devices due to its defect tolerance, high carrier density, and angle-tunable electronic properties. However, fundamental understanding of twist angle-dependent exciton transport remains limited due to challenges in sample preparation and interplays between interlayer coupling and moiré potential. Using transient reflection microscopy (TRM), we systematically studied exciton mobility in chemical vapor deposition-grown (CVD-grown) bilayer WS<sub>2</sub> with different twist angles. At 0°, strong interlayer coupling without moiré potential effects yielded the highest exciton mobility (87.3 cm<sup>2</sup>/V s)- 10-fold greater than monolayer WS<sub>2</sub>-with a 1.06 μm diffusion length, while the 25° sample showed reduced mobility (44.5 cm<sup>2</sup>/(V s)) and shorter diffusion length (0.88 μm) due to weakened coupling and moiré potential effects, and the 60° case exhibited intermediate characteristics. This work demonstrates that interlayer coupling and moiré potential modulation critically determine exciton transport dynamics in layered two-dimensional semiconductors, providing essential guidelines for device engineering.
Authors
- Wenna Du (ORCID: https://orcid.org/0000-0003-0023-0183)
- Yubo Tian (ORCID: https://orcid.org/0000-0002-1077-9308)
- Long Yuan (ORCID: https://orcid.org/0000-0001-5591-9311)
- Yuexing Xia
- Jieyuan Liang
- Shula Chen (ORCID: https://orcid.org/0000-0001-9421-8411)
- Anlian Pan (ORCID: https://orcid.org/0000-0003-3335-3067)
- Shuai Yue (ORCID: https://orcid.org/0000-0003-3613-7271)
- Dong Li (ORCID: https://orcid.org/0000-0003-0391-7060)
- Yuyang Zhang (ORCID: https://orcid.org/0000-0002-9548-0021)
- Xinfeng Liu (ORCID: https://orcid.org/0000-0002-7662-7171)
- Zheng Yuanyuan (ORCID: https://orcid.org/0009-0006-6044-9442)
- Yangguang Zhong (ORCID: https://orcid.org/0000-0002-0871-5321)
Institutions
- University of Science and Technology of China (CN)
- Hunan University (CN)
- Hunan Normal University (CN)
- Center for NanoScience (DE)
- Guangdong University of Petrochemical Technology (CN)
- Division of Materials Science and Engineering (AU)
- National Center for Nanoscience and Technology (CN)
- University of Chinese Academy of Sciences (CN)
- State Key Laboratory of Chemobiosensing and Chemometrics (CN)
Publication Details
- Journal
- Nano Letters
- Published
- 2025-03-04
- DOI
- https://doi.org/10.1021/acs.nanolett.5c00027
- Citations
- 9
- Primary Topic
- Perovskite Materials and Applications
- Type
- article
- Field-Weighted Citation Impact
- 6.57
Funders
- National Natural Science Foundation of China
- Chinese Academy of Sciences
- Natural Science Foundation of Hunan Province
- Youth Innovation Promotion Association of the Chinese Academy of Sciences
- National Key Research and Development Program of China
- National Science Fund for Distinguished Young Scholars