Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 64: Scanning Probe Techniques: Method development
O 64.12: Poster
Dienstag, 21. März 2017, 18:30–20:30, P2-OG3
A Scanning Tunneling Microscope with femtosecond optical near-field excitation — •Benjamin Schröder, Katharina Kaiser, Steffen Bornemann, Claus Ropers, and Martin Wenderoth — IV. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen
Photochemical reactions on metal oxide surfaces are governed by the site-specific surface structure, including defect concentration and distribution. To investigate these highly-localized optical excitation mechanisms, we implemented a low-temperature Scanning Tunneling Microscope operating under ultra high vacuum conditions. Our setup features stable imaging conditions with atomic resolution under pulsed optical excitation of the tip-sample gap at peak intensities up to 1 GW/cm2.
Using this setup, we are able to desorb hydrogen adatoms and move oxygen vacancies from TiO2 surfaces by applying current or voltage pulses [1,2]. Currently, we are investigating the possibility of stimulated desorption and diffusion processes by optical near-field excitation.
This project is financially supported by the DFG in the SFB 1073 (project C4).
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Minato et al., ACS Nano 9, 6837 (2015)