Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 71: 2D Materials beyond Graphene -Dynamics and Excitation
(Joint session of DS, DY, HL, MA, O and TT organized by O)
TT 71.2: 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.