Force microscopy experiments: From Nanotribology to Molecular Electronics
Ernst Meyer (Institute of Physics, University of Basel, Switzerland)
Force microscopy is a versatile instrument to investigate physical phenomena on surfaces. The first emphasis is on the study of friction on the nanometer-scale, also called nanotribology. It will be shown that atomic-scale stick-slip is relatively well understood, where the dependence on velocity and normal force is experimentally investigated and interpreted in terms of an extended Tomlinson model. It is essential to include thermal actuation to understand the observed phenomena. Recently, it has been shown that atomic friction can be controlled with rather high accuracy by electrostatic actuation [1]. The second part will be focussed on the imaging of molecules on insulators, which has some relevance for future molecular electronics applications. It will be shown that the controlled immobilization of molecules on insulators is a major issue. Nanometer-sized pits on ionic crystals are found to be effective traps of molecules, which were otherwise mobile on the unmodified, flat surfaces [2].
[1] A. Socoliuc, S. Maier, O. Pfeiffer,E. Gnecco, A. Baratoff, R. Bennewitz and E. Meyer, Atomic-Scale Control of Friction by Actuation of Nanometer-Sized Contacts" Science, 313, 207, July 14 (2006).
[2] L. Nony, E. Gnecco, A. Baratoff, A. Alkauskas, R. Bennewitz, O. Pfeiffer, S. Maier, A. Wetzel, E. Meyer and C. Gerber, Observation of individual molecules trapped on a nanostructured insulator, Nanoletters 4, 2189 (2004).
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