Cascaded emission of single photons from the biexciton in monolayered WSe2
Abstract
Monolayers of transition metal dichalcogenide materials emerged as a new material class to study excitonic effects in solid state, as they benefit from enormous Coulomb correlations between electrons and holes. Especially in WSe2, sharp emission features have been observed at cryogenic temperatures, which act as single photon sources. Tight exciton localization has been assumed to induce an anharmonic excitation spectrum; however, the evidence of the hypothesis, namely the demonstration of a localized biexciton, is elusive. Here we unambiguously demonstrate the existence of a localized biexciton in a monolayer of WSe2, which triggers an emission cascade of single photons. The biexciton is identified by its time-resolved photoluminescence, superlinearity and distinct polarization in micro-photoluminescence experiments. We evidence the cascaded nature of the emission process in a cross-correlation experiment, which yields a strong bunching behaviour. Our work paves the way to a new generation of quantum optics experiments with two-dimensional semiconductors.
Citation
He , Y-M , Iff , O , Baumann , V , Davanco , M , Srinivasan , K , Höfling , S & Schneider , C 2016 , ' Cascaded emission of single photons from the biexciton in monolayered WSe 2 ' , Nature Communications , vol. 7 , 13409 . https://doi.org/10.1038/ncomms13409
Publication
Nature Communications
Status
Peer reviewed
ISSN
2041-1723Type
Journal article
Rights
Copyright the Authors 2016. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
Description
This work has been supported by the State of Bavaria and the European Research Council (Project UnLiMIt-2D).Collections
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