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 e...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>10^(12)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.展开更多
基金S.A.M.acknowledges the Lee Lucas chair in physics and funding by the EPSRC(EP/WO1707511)the Australian Research Council(Centre of Excellence in Future Low-Energy Electronics Technologies-CE 170100039)+1 种基金L.S.further acknowledges funding support through a Humboldt Research Fellowship from the Alexander von Humboldt FoundationOur studies were partially supported by the Center for NanoScience(CeNS)-Faculty of Physics,Ludwig-Maximilians University Munich.
文摘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>10^(12)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.
