Impact of temperature on the brightening of neutral and charged dark excitons in WSe <sub>2</sub> monolayer
Abstract Optically dark states play an important role in the electronic and optical properties of monolayers (MLs) of semiconducting transition metal dichalcogenides. The effect of temperature on the in‐plane‐field activation of the neutral and charged dark excitons is investigated in a WSe 2 ML encapsulated in hexagonal BN flakes. The brightening rates of the neutral dark ( X D ) and grey ( X G ) excitons and the negative dark trion ( T D ) differ substantially at particular temperature. More importantly, they weaken considerably by about 3–4 orders of magnitude with temperature increased from 4.2 K to 100 K. The quenching of the dark‐related emissions is accompanied by the two‐order‐of‐magnitude increase in the emissions of their neutral bright counterparts, i . e . neutral bright exciton ( X B ) and spin‐singlet ( T S ) and spin‐triplet ( T T ) negative trions, due to the thermal activations of dark states. Furthermore, the energy splittings between the dark X D and T D complexes and the corresponding bright X B , T S , and T T ones vary with temperature rises from 4.2 K to 100 K. This is explained in terms of the different exciton–phonon coupling for the bright and dark excitons stemming from their distinct symmetry properties.
Authors
- Dipankar Jana (ORCID: https://orcid.org/0000-0001-9935-4885)
- A. Babiński (ORCID: https://orcid.org/0000-0002-5591-4825)
- Igor Antoniazzi (ORCID: https://orcid.org/0000-0002-0803-6011)
- Takashi Taniguchi (ORCID: https://orcid.org/0000-0002-1467-3105)
- Kenji Watanabe (ORCID: https://orcid.org/0000-0003-3701-8119)
- Łucja Kipczak (ORCID: https://orcid.org/0000-0003-1266-0201)
- Natalia Zawadzka (ORCID: https://orcid.org/0000-0002-3282-9513)
- Małgorzata Zinkiewicz (ORCID: https://orcid.org/0000-0002-7472-5501)
- Magdalena Grzeszczyk (ORCID: https://orcid.org/0000-0001-6861-3098)
- Maciej R. Molas (ORCID: https://orcid.org/0000-0002-5516-9415)
- C. Faugeras (ORCID: https://orcid.org/0000-0002-9615-8739)
- M. Potemski (ORCID: https://orcid.org/0000-0001-8881-6618)
Institutions
- Warsaw University of Technology (PL)
- Centre National de la Recherche Scientifique (FR)
- National University of Singapore (SG)
- National Institute for Materials Science (JP)
- Laboratoire National des Champs Magnétiques Intenses (FR)
- University of Warsaw (PL)
- Université Grenoble Alpes (FR)
Publication Details
- Journal
- Nanophotonics
- Published
- 2024-11-18
- DOI
- https://doi.org/10.1515/nanoph-2024-0385
- Citations
- 2
- Primary Topic
- 2D Materials and Applications
- Type
- article
- Field-Weighted Citation Impact
- 0.23
Funders
- Ministry of Education, Culture, Sports, Science and Technology
- Fundacja na rzecz Nauki Polskiej
- Narodowe Centrum Nauki
- Narodowym Centrum Nauki
- Centre National de la Recherche Scientifique
- Japan Society for the Promotion of Science