Radiative suppression of exciton-exciton annihilation in a two-dimensional semiconductor.

Two-dimensional (2D) semiconductors possess strongly bound excitons, opening novel opportunities for engineering light-matter interaction at the nanoscale. However, their in-plane confinement leads to large non-radiative exciton-exciton annihilation (EEA) processes, setting a fundamental limit for their photonic applications. In this work, we demonstrate suppression of EEA via enhancement of light-matter interaction in hybrid 2D semiconductor-dielectric nanophotonic platforms, by coupling excitons in WS2 monolayers with optical Mie resonances in dielectric nanoantennas. The hybrid system reaches an intermediate light-matter coupling regime, with photoluminescence enhancement factors up to 102. Probing the exciton ultrafast dynamics reveal suppressed EEA for coupled excitons, even under high exciton densities >1012 cm-2. We extract EEA coefficients in the order of 10-3, compared to 10-2 for uncoupled monolayers, as well as a Purcell factor of 4.5. Our results highlight engineering the photonic environment as a route to achieve higher quantum efficiencies, for low-power hybrid devices, and larger exciton densities, towards strongly correlated excitonic phases in 2D semiconductors. © 2023. Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP), CAS.

Citation

Luca Sortino, Merve Gülmüs, Benjamin Tilmann, Leonardo de S Menezes, Stefan A Maier. Radiative suppression of exciton-exciton annihilation in a two-dimensional semiconductor. Light, science & applications. 2023 Aug 24;12(1):202

PMID: 37620298

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