Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 16: Scanning probe methods II
O 16.1: Talk
Monday, March 26, 2012, 16:00–16:15, MA 043
ncAFM Force Spectroscopy of Long Range Tip Sample Interaction using FIM Characterized Tip — •Jens Falter1, Daniel-Alexander Braun1, Gernot Langewisch1, Hendrik Hölscher3, Harald Fuchs1, and André Schirmeisen2 — 1Center for Nanotechnology (CeNTech) and Institute of Physics, University of Muenster (WWU) — 2Institute of Applied Physics (IAP), Justus-Liebig-University Giessen — 3Karlsruher Institute for Technology (KIT), Karlsruhe
Beyond imaging, non contact Atomic Force Microscopy (ncAFM) measures interaction forces between the sample surface atoms and the probing tip with atomic precision. Nevertheless, the full interaction geometry is often unknown because of the unknown tip structure. A comparison with theory to understand the underlying contrast mechanism therefore is often not possible. The implementation of the qplus sensor [1] allows combining ncAFM with the Field Ion Microscope (FIM)[2] which provides the tip structure with atomic precision. Here we present ncAFM force spectroscopy experiments with a FIM-characterized tip. Combining these microscopy techniques, the tip structure can be determined and compared with analytical models based on the given tip geometry. A comparison of our distance and voltage dependent force curves with theoretical models is in excellent agreement for the electrostatic force interactions while the van der Waals contribution is underestimated by the models. Furthermore, our approach provides a quantitative value for the absolute distance. [1] F.J. Giessibl, Appl. Phys. Lett. 76, 1470 (2000) [2] E.W. Müller, Z. Physik 131, 136 (1951)