Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 28: Plasmonics and Nanooptics IV: Light-Matter Interaction
O 28.2: Vortrag
Dienstag, 21. März 2017, 10:45–11:00, TRE Ma
Tip-Enhanced Raman Spectroscopy of a MoS2 / Au Nanoparticle (2D crystal/Plasmonic) Heterostructure — •Mahfujur Rahaman1, Raul D Rodriguez1, Gerd Plechinger2, Stefan Moras1, Christian Schüller2, Tobias Korn2, and Dietrich RT Zahn1 — 1Semiconductor Physics, Technische Universität Chemnitz, Germany — 2Fakultät für Physik, Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Germany
Tip-enhanced Raman spectroscopy (TERS) has been rapidly improved over the last decade and opened up opportunities to study phonon properties of materials on a nanometre scale. We report on TERS of a 4-layer MoS2 flake deposited onto a Au nanostructured surface, thus forming a 2D crystal/plasmonic heterostructure. Au nanotriangles are prepared by nanosphere lithography and then MoS2 is mechanically exfoliated on top of it. The TERS spectra are acquired under resonance conditions at 638 nm excitation using a Xplora/AIST-NT TERS system. We obtain a spatial resolution of 10 nm in TERS imaging. We observe the highest enhancement of the Raman intensity of MoS2 on top of Au nanotriangles due to the strong electromagnetic confinement between the tip and single triangle. Our results enable us to determine the local strain in MoS2 induced after the heterostructure formation. The maximum frequency shift of E2g mode is determined to be 3.2 cm-1 which is equivalent to 1% of biaxial strain induced in the film. Our results will help the understanding of the structural and mechanical degrees of freedom to the nanoscale optoelectronic properties of future MoS2/plasmonic based devices.