Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 75: Nanotribology II
O 75.5: Vortrag
Donnerstag, 25. März 2010, 16:00–16:15, H36
Frictional properties of a mesoscopic contact with engineered surface roughness — •Johannes Sondhauß1,2, Harald Fuchs1,2, and André Schirmeisen1,2 — 1Institute of Physics, University of Münster, Münster, Germany — 2Center for Nanotechnology (CeNTech), University of Münster, Münster, Germany
Friction force microscopy (FFM) is a standard tool to perform friction experiments on the nanoscale. However, with a conventional tip used in FFM, only contact areas of a few nm2 are realizable. To get access to friction experiments with larger contact geometries typical for, e.g., MEMS, new concepts to prepare mesoscale tip-sample contacts are necessary. In this work, we used a focused ion beam (FIB) to engineer both sliding partners, i.e. tip and sample. Cantilever with spherical apexes with diameters of 5 and 16 µm were fabricated by attaching a titanium microparticle to the modified tips. To investigate the influence of interface roughness of the contact, a silicon surface was patterned with arrays of grooves with a lattice periodicity ranging from 1 to 9 µm and a depth of 26 nm. The average friction coefficient was determined systematically for the two tips as a function of the lattice periodicity of the sample grooves. For both tips the maximum friction force was found where the geometry of the spherical tip and the lattice are commensurate. These findings highlight the importance of surface structure on tribological properties of mesoscale contacts.