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Dark exciton-exciton annihilation in monolayer WSe2
Physical Review B, Volume: 104, Issue: 24
Swansea University Author:
Roland Gillen
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DOI (Published version): 10.1103/physrevb.104.l241406
Abstract
The exceptionally strong Coulomb interaction in semiconducting transition-metal dichalcogenides (TMDs) gives rise to a rich exciton landscape consisting of bright and dark exciton states. At elevated densities, excitons can interact through exciton-exciton annihilation (EEA), an Auger-like recombina...
Published in: | Physical Review B |
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ISSN: | 2469-9950 2469-9969 |
Published: |
American Physical Society (APS)
2021
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Online Access: |
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URI: | https://cronfa.swan.ac.uk/Record/cronfa66653 |
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Abstract: |
The exceptionally strong Coulomb interaction in semiconducting transition-metal dichalcogenides (TMDs) gives rise to a rich exciton landscape consisting of bright and dark exciton states. At elevated densities, excitons can interact through exciton-exciton annihilation (EEA), an Auger-like recombination process limiting the efficiency of optoelectronic applications. Although EEA is a well-known and particularly important process in atomically thin semiconductors determining exciton lifetimes and affecting transport at elevated densities, its microscopic origin has remained elusive. In this joint theory-experiment study combining microscopic and material-specific theory with time- and temperature-resolved photoluminescence measurements, we demonstrate the key role of dark intervalley states that are found to dominate the EEA rate in monolayer WSe2. We reveal an intriguing, characteristic temperature dependence of Auger scattering in this class of materials with an excellent agreement between theory and experiment. Our study provides microscopic insights into the efficiency of technologically relevant Auger scattering channels within the remarkable exciton landscape of atomically thin semiconductors. |
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College: |
Faculty of Science and Engineering |
Funders: |
Wethank Maja Feierabend (Chalmers) and Paulo Eduardo de Faria Junior and Kai-Qiang Lin (University of Regensburg) for fruitful discussions. This project received funding from Deutsche Forschungsgemeinschaft via CRC 1083 (Project No. B09), Emmy Noether Initiative (CH 1672/1, ProjectID 287022282), CRC 1277 (Project-ID 314695032, Project No. B05), CRC 953 (Project No. B13), the European Unions Horizon 2020 research and innovation program under Grant agreement No. 881603 (Graphene Flagship) and the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter ct.qmat (EXC 2147, Project-ID: 390858490). Furthermore, we are thankful to Vinnova for the support via the 2D-TECH competence center. K.Watanabe and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan (Grant No. JPMXP0112101001) and JSPS KAKENHI (Grants No. JP19H05790 and No. JP20H00354). |
Issue: |
24 |