Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 17: Interfaces and surfaces

HL 17.1: Talk

Monday, March 11, 2013, 15:00–15:15, H15

Photoluminescence spectroscopy of singlelayer MoS₂ — •Gerd Plechinger, Stefanie Heydrich, Johannes Schmutzler, Jonathan Eroms, Dieter Weiss, Christian Schüller, and Tobias Korn — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany

Complementary to the gapless material graphene, the transition-metal dichalcogenide MoS₂ is a promising two-dimensional layered semiconductor for future ultrathin nanoelectronic and optoelectronic devices. Subnanometer thickness, large bandgap in the visible range and ultrafast carrier dynamics make it interesting for devices like transistors, ultrafast optical switches or photovoltaic applications.

Our monolayer MoS₂ flakes were prepared by the well-known mechanical cleavage method. With a µPL experimental setup, we can perform photoluminescence spectroscopy at temperatures from 4 K up to room temperature. Under different external influences like temperature, magnetic fields or circular polarisation of the exciting laser light, we investigated the behavior of the A and B excitons, arising from transitions from the spin-orbit split valence band to the conduction band at the K-point of the Brillouin zone. Thereby, we could gather information about charged and neutral excitons and a possible valley polarisation. Furthermore, we could produce monolayer regions out of few-layer flakes via intense focussed laser radiation.

Financial support by Deutsche Bundesstiftung Umwelt is gratefully acknowledged.