Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 22: Transport: Poster Session
TT 22.32: Poster
Mittwoch, 27. Februar 2008, 14:00–18:00, Poster B
In-situ fabrication of nanobridges under ultra-high vacuum conditions — •Dominik Stöffler1, Hilbert v. Löhneysen1,2, and Regina Hoffmann1 — 1Physikalisches Institut and DFG Center for Functional Nanostructures (CFN), Universität Karlsruhe, D-76128 Karlsruhe, Germany — 2Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe, Germany
Contacting single molecules with nanostructured metallic leads remain a challenge, in spite of numerous attempts. We investigate nanocontact formation by thermally assisted electromigration of gold nanowires. The nanowires are prepared by electron beam lithography. An automatic feed-back allows to follow a line of constant dissipated power at the nanocontact, which leads to a gradual thinning of the wire until a small gap is formed. The fabricated gaps are smaller than 10 to 20 nm. By following the line of constant power, we estimate an increase of the temperature of the contact from 350 K in the thermal regime at the beginning, to 650 K in the ballistic regime at the end of the overall electromigration process. Due to the lithography process, leftovers such as PMMA remain on the metallic contacts, which eventually affect transport measurements with molecules. We introduce a promising alternative method to fabricate and contact clean metallic nanostructures, using evaporation through a mask under ultra-high vacuum. These structures can eventually be separated by electromigration to accommodate single molecules.