Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 38: Poster Session Transport
TT 38.26: Poster
Mittwoch, 16. März 2011, 14:00–18:00, P3
Electronic transport through switchable molecules — •Bernd Briechle1, Nikola Treska1, Dima Sysoiev2, Jannic Wolf2, Youngsang Kim1, Johannes Boneberg1, Thomas Huhn2, Ulrich Groth2, Ulrich Steiner2, Artur Erbe3, and Elke Scheer1 — 1Department of Physics, University of Konstanz, Germany — 2Department of Chemistry, University of Konstanz, Germany — 3Forschungszentrum Dresden-Rossendorf, Dresden, Germany
We investigate transport properties of molecules in liquid solvent at room temperature. For that purpose we use lithographically fabricated Mechanically Controllable Break Junctions (MCBJs) to generate atomic-size contacts and atomically sharp tips to contact the molecules. We study molecular switches for which reversible switching from an opened to a closed conjugated backbone via light irradiation is expected. The molecular switches feature thiol- or nitrogen-based endgroups for a strong bond to the metal. Analysis is based on statistics of conductance traces recorded during opening and closing the junction, and on current-voltage characteristics taken at constant electrode distance. It has been shown that the latter can be described by a simple transport model involving a single broadened molecular orbital. Fitting the experimental current-voltage characteristics to this model, we can extract the strength of the molecule-metal bond as well as the energy of the molecular orbital next to the Fermi level. This analysis enables us to determine promising combinations of metal and molecule endgroup for stable and reproducible contacting which is a crucial requirement for our transport studies.