Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 76: 2D Materials beyond Graphene: Dynamics and Excitation

O 76.2: Vortrag

Donnerstag, 10. März 2016, 11:00–11:15, S054

Exciton dynamics in two-dimensional materials with strong spin-orbit interaction: MoSe₂ versus WSe₂ — •Daniel Schmidt¹, Tillmann Godde², Johannes Schmutzler¹, Marc Aßmann¹, Jörg Debus¹, Freddie Withers³, Osvaldo Del Pozo-Zamudio², Konstantin S. Novoselov³, Andre Geim³, Manfred Bayer¹, and Alexander Tartakovskii² — ¹Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany — ²Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK — ³School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK

Monolayers of semiconducting transition metal dichalcogenides such as MoS₂, WS₂, MoSe₂ and WSe₂ have attracted considerable attention following the discovery of the indirect-to-direct bandgap transition from bulk to monolayer material and the coupling of spin and valley degrees of freedom in atomically thin layers. An important characteristic of these compounds is the strong spin-orbit interaction, which leads to a splitting between dark and bright exciton sub-bands. A detailed understanding of dark and bright exciton dynamics and non-radiative processes is important for light emitting applications as has been demonstrated in other systems such as phosphorescent organic light emitting diodes. We measure time-integrated and -resolved PL in monolayers of MoSe₂ and WSe₂ in a wide range of temperatures from 10 to 300K and gain insights into the exciton and trion dynamics. Our study reveals similar carrier dynamics for both materials, whereas pronounced differences have been observed for the overall PL intensities.