Rahaman, Mahfujur and Rodriguez, Raul D. and Plechinger, Gerd and Moras, Stefan and Schueller, Christian and Korn, Tobias and Zahn, Dietrich R. T. (2017) Highly Localized Strain in a MoS2/Au Heterostructure Revealed by Tip-Enhanced Raman Spectroscopy. NANO LETTERS, 17 (10). pp. 6027-6033. ISSN 1530-6984, 1530-6992
Full text not available from this repository. (Request a copy)Abstract
Tip-enhanced Raman spectroscopy (TERS) has been rapidly improved over the past decade and opened up opportunities to study phonon properties of materials at the nanometer scale. In this Letter, we report on TERS of an ultrathin MoS2 flake on a nanostructured Au on silicon surface forming a two-dimensional (2D) crystal/plasmonic heterostructure. Au nanostructures (shaped in triangles) are prepared by nanosphere lithography, and then MoS2 is mechanically exfoliated on top of them. The TERS spectra acquired under resonance conditions at 638 nm excitation wavelength evidence strain changes spatially localized to regions as small as 25 nm in TERS imaging. We observe the highest Raman intensity enhancement for MoS2 on top of Au nanotriangles due to the strong electromagnetic confinement between the tip and a single triangle. Our results enable us to determine the local strain in MoS2 induced during heterostructure formation. The maximum frequency shift of Egg mode is determined to be (4.2 0.8) cm(-1), corresponding to 1.4% of biaxial strain induced in the MoS2 layer. We find that the regions of maximum local strain correspond to the regions of maximum topographic curvature as extracted from atomic force microscopy measurements. This tip-enhanced Raman spectroscopy study allows us to determine the built-in strain that arises when 2D materials interact with other nanostructures.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SINGLE-LAYER MOS2; TRANSITION-METAL DICHALCOGENIDES; ATOMICALLY THIN MOS2; MONOLAYER MOS2; PHOTOLUMINESCENCE EMISSION; BILAYER MOS2; NANOSCALE; WSE2; MICROSCOPY; GRAPHENE; Tip-enhanced Raman spectroscopy (TERS); transition metal dichalcogenides (TMDC); MoS2; two-dimensional materials; strain; plasmonics |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Chair Professor Lupton > Group Christian Schüller |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 14 Dec 2018 13:19 |
| Last Modified: | 20 Feb 2019 11:01 |
| URI: | https://pred.uni-regensburg.de/id/eprint/2104 |
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