Berlin 2018 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 2: 2D Materials: Session I (joint session DS/CPP/HL)
DS 2.14: Vortrag
Montag, 12. März 2018, 13:00–13:15, H 2032
Suppression of inhomogeneous broadening of excitons and trions in encapsulated MoSe2 monolayers — •Max Waldherr1, Jacob Goddard1, Nils Lundt1, Sefaattin Tongay2, Kenji Watanabe3, Takashi Taniguchi3, Sven Höfling1,4, and Christian Schneider1 — 1Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — 2School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, USA — 3National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan — 4SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, United Kingdom
Two-dimensional transition metal dichalcogenides offer a rich platform for the investigation of light-matter coupling effects due to unique effects such as spin-valley locking. In the monolayer limit the optical properties of these materials are highly sensitive to surface effects, hence the exciton and trion resonances undergo inhomogeneous broadening by surface impurities. We present a method to reduce the linewidth of these resonances involving encapsulation between two ultra-thin hexagonal boron nitride layers and thermal annealing in an argon-hydrogen atmosphere. With this technique inhomogeneous broadening is suppressed effectively which manifests in a Lorentzian line shape and improved optical quality. Moreover, the spectral weight of the exciton increases and the linewidths of the exciton and trion reduce to 2.9 and 2.4 meV, respectively.