Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures
O 37.43: Poster
Dienstag, 1. April 2014, 18:30–22:00, P2
Scanning near-field optical microscopy and nano-FTIR spectroscopy on sub-nanometer MoS2 structures by using synchrotron radiation — •Georg Ulrich1, Piotr Patoka1, Peter Hermann2, Ariana Nguyen3, John Mann3, Arne Hoehl2, Burkhard Beckhoff2, Ludwig Bartels3, Peter Dowben4, Gerhard Ulm2, and Eckart Rühl1 — 1Physikalische und Theoretische Chemie, Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany — 2Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, Berlin, 10587, Berlin, Germany — 3Department of Chemistry, University of California Riverside, 0124 Pierce Hall, Riverside, California, U.S.A. 92521 — 4Department of Physics and Astronomy, University of Nebraska, Lincoln, T. Jorgensen Hall, Lincoln, Nebraska, U.S.A. 68588-0299
We report on IR-spectromicroscopy on MoS2 demonstrating the successful coupling of scattering type scanning near-field optical microscopy (s-SNOM) with a synchrotron radiation infrared source, provided by the electron storage ring Metrology Light Source (MLS). The technique provides high spatial resolution (<50 nm) spectromicroscopy in the infrared regime with chemical selectivity from nano-Fourier-transform-infrared (nano-FTIR) spectroscopy. The used synchrotron radiation has the advantage compared to lasers, that it covers the entire infrared regime, ranging from the near- to the far-infrared. The correlation of topographically well defined islands grown by chemical vapor deposition, as determined by atomic force microscopy, with the IR signature of MoS2 is illustrated by s-SNOM the approach.
We will present the results on optical mapping of MoS2 monolayers on SiO2 gained with a tunable CO2-laser and the influence of such MoS2 islands on SiO2-phonon resonance by means of nano-FTIR measurements with broadband synchrotron-radiation. The results suggest either a significant carrier concentration in MoS2, likely as a result of substrate interactions, or strong MoS2-SiO2 substrate dipole interactions.