Cascaded emission of single photons from the biexciton in monolayered WSe2

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 WSe 2 , sharp emission features have been observed at cryogenic temperature...

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Published inNature communications Vol. 7; no. 1; p. 13409
Main Authors He, Yu-Ming, Iff, Oliver, Lundt, Nils, Baumann, Vasilij, Davanco, Marcelo, Srinivasan, Kartik, Höfling, Sven, Schneider, Christian
Format Journal Article
LanguageEnglish
Published London Nature Publishing Group UK 10.11.2016
Nature Publishing Group
Nature Portfolio
Subjects
639/624/1020
639/624/399/1017
Electrons
Humanities and Social Sciences
Molecular beam epitaxy
multidisciplinary
Optical properties
Physics
Science
Science (multidisciplinary)
Semiconductors
Spectrum analysis
China
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Summary: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 WSe 2 , 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 WSe 2 , 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. Atomically thin transition metal dichalcogenides constitute an ideal platform to investigate solid state excitonic effects. Here, the authors provide experimental evidence of a localized biexciton in a monolayer of WSe 2 , which induces an emission cascade of single photons.
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ISSN:2041-1723
2041-1723
DOI:10.1038/ncomms13409