Berlin 2012 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 21: Transport: Nanoelectronics I - Quantum Dots, Wires, Point Contacts 3
TT 21.8: Talk
Tuesday, March 27, 2012, 11:30–11:45, BH 334
Scanning probe microscopy imaging of metallic nanocontacts prepared by electromigration — •Dominik Stöffler1, Shawn Fostner2, Hilbert v. Löhneysen1,3, Peter Grütter2, and Regina Hoffmann-Vogel1 — 1Karlsruher Institut für Technologie, Physikalisches Institut, 76131 Karlsruhe — 2Department of Physics, McGill University, Montreal, Canada — 3Karlsruher Institut für Technologie, Institut für Festkörperphysik, 76021 Karlsruhe
Controlled electromigration of thin metallic films represents a promising technique for fabricating nanometer-sized gaps for possible applications in molecular electronics. We show scanning force microscopy measurements of metallic nanocontacts that are formed during controlled electromigration cycles. The nanowires used for the thinning process are fabricated by shadow evaporation. During the first few electromigration cycles an overall slit in the nanocontact is formed, with a few grains still maintaining metallic contact. At a later stage the remaining grains disintegrate and their remnants accumulate in regions away from the slit. Resistance measurements during the electromigration cycle suggest that first the whole wire is heated. During the subsequent thinning process the current apparently passes through several smaller contacts and less power is needed for electromigration. We also discuss the influence of the environment (ambient, ultra-high vacuum) on the electromigration process.