Regensburg 2007 – scientific programme

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SYOE: Symposium Organic Thin Film Electronics: From Molecular Contacts to Devices

SYOE 8: Poster Session SYOE

SYOE 8.1: Poster

Tuesday, March 27, 2007, 18:00–20:00, Poster B

Controlling the shape of Nanogaps for single molecular contacts manufactured by directed Electromigration — •Victor Marinov, Arne Hoppe, and Veit Wagner — School of Engineering and Science, International University Bremen, Campus Ring 8, 28759 Bremen, Germany

Controlled fabrication of nanogaps separating two metal electrodes are of crucial importance for single molecule electronics. Among others, electromigration is a well-known technique to form such nanogaps with the inherent advantage to allow for an additional gate electrode. We report on a study to control the shape and the geometry of nanogaps in gold nano-wires on silicon oxide, which also serves as an insulator to the third electrode. We present a new approach, which allows forming of well-defined self-centered nanogaps by using an AC current source as well as asymmetric gap-formation in case a DC current source is applied. Combining both techniques with an intelligent active feed-back loop for the applied voltage in dependence of the measured conductivity allows to get control over a wide range of different shapes of the junction as well as on the height profile of the resulting pair of electrodes. This approach has proven to be extremely robust against initial wire width and yields nanogaps of very well defined mesoscopic shape at room temperature.