Dresden 2017 – scientific programme

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O: Fachverband Oberflächenphysik

O 32: Focus Session: Charge Transport at Surfaces and Nanostructures with Multi-probe Techniques I

O 32.4: Talk

Tuesday, March 21, 2017, 11:30–11:45, WIL C307

In-situ electro-migration studies on silver(Ag) contacts for nanogap fabrication — •Atasi Chatterjee¹, Ejvind Olsen¹, Frederik Edler¹, Torsten Heidenblut², Christoph Tegenkamp¹, and Herbert Pfnür¹ — ¹Leibniz Universität Hannover,Institut für Festkörperphysik, 30167, Hannover, Germany — ²Leibniz Universität Hannover, Institut für Werkstoffkunde, 30823, Hannover,Germany

With the aim to create nanometer-spaced silver( Ag) electrodes as test-beds for molecular electronic studies, the process of electro-migration is adopted amongst the different methods available for fabricating atomic contacts. With the help of a 4-tip SEM/STM setup, the lithographically patterned silver (Ag) structures are probed efficiently with an in-situ monitoring of the electro-migration process using the SEM and STM. The step-by-step morphological changes are observed close to the atomic scale, which is an important pre-requisite for the understanding of the phenomena at nanoscale. Temperature dependent and geometry dependent measurements are performed to separate thermal diffusion from electro-migration. All measurements are done using a feedback controlled lab-view program. The well-defined conductance plateaus obtained as a function of time are the characteristic to atomic scale gaps. Tunneling characteristics were analyzed using I-V curves in Fowler-Nordheim representation. In order to better locate these gaps, a focused ion beam (FIB) is used to reduce the cross-section of these wires. With the reduced cross-section, we characterize the gaps of nearly atomic size with an STM and SEM.