Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 37: Scanning Probe Techniques

O 37.10: Poster

Tuesday, March 17, 2015, 18:15–21:00, Poster A

Four Tip Scanning Tunneling Potentiometry Facilitating Low Injection Currents — •Felix Lüpke, Stefan Korte, Vasily Cherepanov, and Bert Voigtländer — Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany, and JARA-Fundamentals of Future Information Technology

We present a multi-tip scanning tunneling potentiometry implementation. While two of the four tips are used to inject a current into a sample, the third tip is scanned across the surface, recording topography and local electrochemical potential quasi-simultaneously by an interrupted feedback loop [1]. The fourth tip is used as a voltage reference probe. Choosing a distance in the µm range for the injection tips results in the current to be almost exclusively injected into the nanostructure to be studied. As a result, a small amount of current ∼µA results in a substantial amount of voltage drop ∼mV. The small currents needed and the straightforward measurement procedure make this application easy to implement in similar four tip setups with a minimum of hardware adjustments. The capability of the presented setup is demonstrated by experimental results on Si and Bi surfaces.

[1] T. Druga, et al., Rev. Sci. Instrum. 81, 083704 (2010)