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HL: Fachverband Halbleiterphysik
HL 24: Poster Session II
HL 24.39: Poster
Dienstag, 13. März 2018, 18:30–20:30, Poster F
Helium Ion Modified Luminescence and Robust Valley Polarization of Atomically Thin MoS2 — •Fabian Merbeler1, Julian Klein1,2, Agnieszka-Beata Kuc3,4, Anna Noliner1, Marcus Altzschner1, Jakob Wierzbowski1, Florian Sigger1, Franz Kreupl5, Jonathan Finley1,2, Ursula Wurstbauer1,2, Alexander Holleitner1,2, and Michael Kaniber1,2 — 1Walter Schottky Institut and Physics-Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany — 2Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 München, Germany — 3Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, University of Leipzig, Linnéstr. 2, D-04103 Leipzig, Germany — 4Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany — 5Department of Hybrid Electronic Systems, Technische Universtität München, Arcisstr. 21, 80333 Munich, Germany
We show a systematic study of the impact of focused helium ions on the optical, vibrational, and valleytronic properties of atomically thin MoS2. The shifting of the first-order Raman modes are explained by a phonon confinement model introducing an effective interdefect distance. We perform ab-initio density functional theory calculations on a variety of defect related morphologies to explain an additional luminescence peak by O2 molecules chemisorbed at monosulphur vacancies. We further observe that an interdefect distance of the size of the free exciton Bohr radius results in a significant reduction of valley polarization, most likely caused by strong intervalley scattering.