Nature of Long-Lived Moiré Interlayer Excitons in Electrically Tunable MoS<sub>2</sub>/MoSe<sub>2</sub> Heterobilayers
Interlayer excitons in transition-metal dichalcogenide heterobilayers combine high binding energy and valley-contrasting physics with a long optical lifetime and strong dipolar character. Their permanent electric dipole enables electric-field control of the emission energy, lifetime, and location. Device material and geometry impact the nature of the interlayer excitons via their real- and momentum-space configurations. Here, we show that interlayer excitons in MoS<sub>2</sub>/MoSe<sub>2</sub> heterobilayers are formed by charge carriers residing at the Brillouin zone edges, with negligible interlayer hybridization. We find that the moiré superlattice leads to the reversal of the valley-dependent optical selection rules, yielding a positively valued g-factor and cross-polarized photoluminescence. Time-resolved photoluminescence measurements reveal that the interlayer exciton population retains the optically induced valley polarization throughout its microsecond-long lifetime. The combination of a long optical lifetime and valley polarization retention makes MoS<sub>2</sub>/MoSe<sub>2</sub> heterobilayers a promising platform for studying fundamental bosonic interactions and developing excitonic circuits for optical information processing.
Authors
- Dhiren M. Kara (ORCID: https://orcid.org/0000-0003-1052-5495)
- Carmem M. Gilardoni (ORCID: https://orcid.org/0000-0001-5318-3363)
- Matthew S. G. Feuer (ORCID: https://orcid.org/0000-0002-2404-3721)
- Sefaattin Tongay (ORCID: https://orcid.org/0000-0001-8294-984X)
- Patrick Hays
- Takashi Taniguchi (ORCID: https://orcid.org/0000-0002-1467-3105)
- Kenji Watanabe (ORCID: https://orcid.org/0000-0003-3701-8119)
- Mete Atatüre (ORCID: https://orcid.org/0000-0003-3852-0944)
- Alisson R. Cadore (ORCID: https://orcid.org/0000-0003-1081-0915)
- Bárbara L. T. Rosa (ORCID: https://orcid.org/0000-0001-9433-3532)
- Andrea C. Ferrari (ORCID: https://orcid.org/0000-0003-0907-9993)
- Evgeny M. Alexeev (ORCID: https://orcid.org/0000-0002-8149-6364)
- James Kerfoot (ORCID: https://orcid.org/0000-0002-6041-4833)
- Carola M. Purser (ORCID: https://orcid.org/0000-0002-4754-4414)
- Evans Javary
- Hao Chen (ORCID: https://orcid.org/0000-0003-3296-670X)
Institutions
- National Institute for Materials Science (JP)
- University of Cambridge (GB)
- École Normale Supérieure - PSL (FR)
- Bridge University (SS)
- Brazilian Center for Research in Energy and Materials (BR)
- Arizona State University (US)
Publication Details
- Journal
- Nano Letters
- Published
- 2024-08-30
- DOI
- https://doi.org/10.1021/acs.nanolett.4c02635
- Citations
- 10
- Primary Topic
- 2D Materials and Applications
- Type
- article
- Field-Weighted Citation Impact
- 1.17
Funders
- European Commission
- Ministry of Education, Culture, Sports, Science and Technology
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek
- Engineering and Physical Sciences Research Council
- European Research Council
- Japan Society for the Promotion of Science
- H2020 European Research Council
- FP7 Ideas: European Research Council
- HORIZON EUROPE European Innovation Council