Regensburg 2016 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 47: Focussed Session: Physics and Application of Emergent 2D-semiconductors and their Heterostructures II
(Joint session of DS and HL, organized by DS)

DS 47.3: Topical Talk

Donnerstag, 10. März 2016, 16:00–16:30, H8

Photonics and polaritonics with van der Waals heterostructures — •Alexander Tartakovskii — Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH, UK

Monolayer films of van der Waals crystals of transition metal dichalcogenides (TMDCs) are direct band gap semiconductors exhibiting excitons with very large binding energies and small Bohr radii, leading to a high oscillator strength of the exciton optical transition. Together with graphene as transparent electrode and hexagonal boron nitride (hBN) as an insulator, TMDC monolayers can be used to produce so-called van der Waals heterostructures. Here we use this approach to make electrically pumped light-emitting quantum wells (LEQWs) and single-photon emitters. We combine this new technology with optical microcavities to demonstrate control of the emitter spectral properties and directionality, making first steps towards electrically injected TMDC lasers. By embedding MoSe2/hBN structures in tuneable microcavities, we enter the regime of the strong light-matter interaction and observe formation of exciton-polaritons. We demonstrate that the magnitude of the characteristic anti-crossing between the cavity modes and the TMDC excitons can be enhanced by embedding a multiple-QW structure, containing two TMDC monolayers separated by an hBN barrier. This work opens a new avenue in the use of van der Waals crystals and heterostructures with a potential for polariton devices operating at room temperature.