Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 76: 2D Materials beyond Graphene: Dynamics and Excitation
O 76.8: Talk
Thursday, March 10, 2016, 12:30–12:45, S054
Optoelectronic properties of sub-nanometer WS2 and TiS3 investigated by scanning near-field optical microscopy and nano-FTIR spectroscopy by using synchrotron radiation — •P. Patoka1, G. Ulrich1, A. Nguyen2, A. Lipatov3, A. Sinitskii3, P. Hermann4, B. Kästner4, A. Hoehl4, L. Bartels2, P. Dowben5, G. Ulm4, and E. Rühl1 — 1Physikalische Chemie, Freie Universität Berlin, Germany — 2Dept. of Chemistry, Univ. of California Riverside, U.S.A. — 3Dept. of Chemistry, Univ. of Nebraska-Lincoln, U.S.A. — 4Physikalisch-Technische Bundesanstalt (PTB), Germany — 5Dept. of Physics and Astronomy, Univ. of Nebraska-Lincoln, U.S.A.
Among the 2D electronic materials that have received increased attention recently are the transition metal dichalcogenides (TMD). These materials, especially below nanometer thickness, exhibit promising optoelectronic properties for applications in low-dimension electronic circuits. The combined use of scattering-type near-field optical microscopy and the broadband synchrotron radiation source MLS (PTB, Berlin) allows for the highly sensitive spectromicroscopic characterization of such 2D semiconductors with a spatial resolution below 30 nm. We will present recent results on near-field imaging and nano-FTIR spectroscopy in mid-infrared regime down to monolayer thick TMD structures. Investigated are optical responses of WS2, such as its interaction with the optical phonon mode of the SiO2 substrate. We will also show evidence for high charge accumulation at the edges of the TiS3 structures revealed by optical mapping using tunable CO2 laser.