Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 99: 2D materials beyond graphene: TMDCs, silicene and relatives IV
O 99.5: Talk
Thursday, March 15, 2018, 16:00–16:15, MA 043
Coupling mechanisms of transition metal dichalcogenides to plasmonic gold nanoparticle arrays — •Jonas Kiemle1,2, Sandra Diefenbach1,2, Sebastian Funke3, Peter Thiesen3, Ursula Wurstbauer1,2, and Alexander W. Holleitner1,2 — 1Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany — 2Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 Munich, Germany — 3Accurion GmbH, Stresemannstr. 30, 87079 Göttingen, Germany
We reveal the manifold interaction mechanisms between monolayers of MoS2 and single layers of plasmon-active gold nanoparticles. The MoS2 shows a ten- to twenty-fold enhanced photoluminescence when it is decorated with the gold nanoparticles. Surprisingly, we detect this enhancement also for excitation energies, which are not resonant to the surface plasmon polaritons of the nanoparticles. Complementary Kelvin probe force measurements indicate a lowering of the work function, when the MoS2 is decorated with the gold nanoparticles. This is in agreement with a reduced band gap for the decorated MoS2 as determined from absorbance measurements. We furthermore demonstrate a dielectric coupling between the two layers by spectroscopic imaging ellipsometry as well as Raman spectroscopy. Combining the various results, we discuss the enhanced photoluminescence in terms of a modified emission pattern of the radiative dipole in the MoS2 monolayers at the presence of the gold nanoparticles.