Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 39: Posters II (Topological insulators; Graphene; Spintronics and spin physics; Quantum information science)

HL 39.10: Poster

Tuesday, March 17, 2015, 14:00–20:00, Poster F

Optical spectroscopy on ultrathin NbSe₂ and NbSe₂-semiconductor heterostructures — •Sven Gelfert¹, Nicola Paradiso¹, Gerd Plechinger¹, Philipp Nagler¹, Philipp Tonndorf², Steffen Michaelis de Vasconcellos², Rudolf Bratschitsch², Christoph Strunk¹, Christian Schüller¹, and Tobias Korn¹ — ¹Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany — ²Physikalisches Institut, Westphälische Wilhelms-Universität Münster, 48149, Münster, Germany

NbSe₂ is a layered transition metal dichalcogenide with a superconducting transition. By applying an exfoliation method, it can be thinned down to a few molecular layers and be transfered onto a Si/SiO₂ substrate. We have produced NbSe₂ flakes with "terraces" of different thickness down to the nanometer scale. In Raman measurements we observed a layer-dependent frequency shift in the characteristic phonon modes.

Furthermore, we have produced heterostructures by combining singlelayer WSe₂ and MoSe₂ with ultrathin NbSe₂. In time-resolved photoluminescence experiments on these heterostructures we observed a dynamic charge transfer between the semiconducting layer and the adjacent NbSe₂. We have analysed the photocarrier dynamics of both, isolated WSe₂/MoSe₂ single layers, and heterostructures, as a function of temperature.