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O: Oberflächenphysik

O 18: Nanostructures II

O 18.3: Vortrag

Dienstag, 28. März 2006, 11:45–12:00, PHY C213

Controllable molecular Ag contacts on Si(100) and Si(111) via electromigration — •Gernot Gardinowski, Jedrzej Schmeidel, Christoph Tegenkamp, and Herbert Pfnür — Institut für Festkörperphysik, Universität Hannover, Appelstrasse 2, 30167 Hannover, Germany

In order to characterize single molecules and nanostructures electrically, contacts with a well-defined geometry and size are essential. We present a electromigration method, that leads to thin vertical and small lateral contacts of high yield, which are particularly interesting for STM/AFM investigations. In a first step, we are using electron beam lithography on a two-resist combination (PMMA/LOR3B) on Si(100) and Si(111). We demonstrate, that it is possible to create nanobridges due to underetching. The latter can be used for a three dimensional stairs-like growth by evaporating of Ag at different angles. Film-thicknesses down to ≈ 4nm and lateral dimensions below 100 nm has been realised so far. This is important for heat dissipation during the planar breakjunction process and also for thin contacts for further investigations via STM/AFM. Contactpads have been tested by SEM/AFM/AES. In a second step, we are using a computer-based controlled electromigration method at ≈ 80 K. First measurements indicates gaps around 1 nm, which has been characterized electrically.