Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 12: Oxides and insulators: Adsorption

O 12.6: Vortrag

Montag, 22. März 2010, 16:15–16:30, H33

Light-induced isomerization of an azobenzene derivate on an insulating surface — •Jörg Henzl and Karina Morgenstern — Universität Hannover, Institut für Festkörperphysik, Abteilung für Atomare und Molekulare Strukturen (ATMOS), Appelstr. 2, 30167 Hannover

Azobenzene molecules and its derivates are highly attractive for switches in molecular electronics and have a high potential in opto-electronic devices as they exhibit a light-induced cis-trans isomerization. Recent studies demonstrated the principle feasibility of isomerization in contact with a metal surface. But circuits on metals are of little technological relevance in contrast to insulators. A model system for an insulating surface is a thin NaCl film grown on metal substrates. Recently, the electron-induced isomerization of amino-nitroazobenzene on NaCl/Ag(111) was shown.[1] In this contribution, we present low temperature scanning tunnelling microscopy measurements of p-hydroxy-azobenzene on thin NaCl films on Ag(111). After depositing at 20 K, single molecules are found on the surface. The reversible isomerization can be triggered either with inelastic tunnelling electrons from the STM tip or with photons from a Hg-arc lamp. We characterize the adsorption geometry of both configurations and discuss the wave-length depend light-induced isomerization. [1] A. Safiei, J. Henzl, and K. Morgenstern, O17.8, DPG conference, Dresden 2009