Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 74: Molecular Electronics and Photonics
TT 74.5: Vortrag
Mittwoch, 14. März 2018, 17:00–17:15, H 3005
Characteristic excitations in conduction through Ag-CO molecular junctions — •Atasi Chatterjee1, Jan Philipp Stöckmann1, Christoph Tegenkamp1,2, and Herbert Pfnür1 — 1Leibniz Universität Hannover, Institut für Festkörperphysik, 30167, Hannover, Germany — 2Technische Universität Chemnitz, Institut für Physik, 09126, Chemnitz, Germany
Ag metallic nano-electrodes with an initial centre width of approximately 20 nm were fabricated using a combination of e-beam lithography (EBL) and focused ion beam (FIB) milling. These structures were thinned by electromigration (EM) to generate atomic point contacts. With the help of a 4-tip SEM / STM setup, the visualization of the structural changes as well as conductance measurements were performed at the same time. Conductance histograms exhibit characteristic signatures of atomic point contacts. Conductance of these point contacts was strongly altered by adsorbed CO, which was deposited in-situ after opening the contact. Sub-G0 plateaus were observed as first signatures of the metal molecule interaction. I-V measurements were performed at sub-G0 values when the conductance was stable for at least 15 mins. The I-V curves are asymmetric with a slightly rectifying behavior for negative voltages. This asymmetry can be attributed to the fact that CO molecule binds preferably to one side of the metallic electrode. From the characteristic changes of slope, resonance features, and change of noise levels at different voltages in the IV measurements, we explain the properties of these Ag-CO molecular junctions.