Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 84: Scanning Probe Techniques: Method Developments
O 84.7: Talk
Thursday, March 10, 2016, 16:45–17:00, S054
Imaging of 2D electronic structures with Intermodulation — •Riccardo Borgani1, Erik A. Tholén2, and David B. Haviland1 — 1Nanostructure Physics, KTH Royal Institute of Technology, Stockholm, Sweden — 2Intermodulation Products AB, Segersta, Sweden
We present a Scanning Probe Microscopy (SPM) technique to image the contact potential difference (CPD) between the tip of a conducting cantilever and the sample surface. A multifrequency drive is used to probe the nonlinear electrostatic force and extract the CPD from the intermodulation signals close to the cantilever resonance. This measurement scheme allows for a very high signal to noise ratio and excellent lateral resolution, and it eliminates the DC feedback to null CPD, used on all other types of Kelvin Probe Force Microscopy. The absence of a DC bias is of particular importance with those samples where electrical doping could alter the properties under investigation. We present a theoretical derivation of the technique, as well as it's application for high-resolution imaging of mono- and multi- layer graphene and graphene nano-ribbons, and patterned two-dimensional electron gas devices.
Reference
R. Borgani, D. Forchheimer, J. Bergqvist, P.-A. Thorén, O. Inganäs, and D. B. Haviland, Appl. Phys. Lett. 105, 143113 (2014).