Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: Scanning Probe Methods I

O 44.3: Vortrag

Mittwoch, 13. März 2013, 11:00–11:15, H33

Investigations on nanocantilever dynamics in intermittent-contact AFM — •Moid Bhatti, Ivo Knittel, Uwe Schmitt, Andreas Englisch, and Uwe Hartmann — Institute of Experimental Physics, Saarland University, 66041 Saarbruecken, Germany

High speed (video rate and beyond) atomic force microscopy (AFM) requires not only fast feedback with a bandwidth exceeding 100 kHz - for which solutions are emerging - but also cantilever resonant frequencies in the MHz range. Nanocantilevers (NC) can fulfill this requirement motivating an understanding of the NC-sample interaction.

We are studying contact mechanics of the cantilever-sample system in the dynamic mode AFM using NC of various types: (1) nanowires (NW) grown on a substrate (the dynamic behavior of which is equivalent to a cantilever with a NW attached to it), (2) carbon nanotubes attached to an AFM cantilever, (3) focused-ion-beam-(FIB)-structured NC, (4) a FIB-structured NC at the tip of an optical fiber, whereby the light transmission capability of the fiber can be utilized for the integrated detection of the NC oscillation.

We will present different NC, FEM simulations of NC resonances, a detection mechanism and AFM imaging with NC. The contact stiffness with NC can be very low resulting in a characteristic tip-sample force-distance relation. Distance-dependent resonance curves of an AFM cantilever interacting with a static NW and of a NC tapping on a sample showing the existence of a third state of cantilever dynamics besides the well-known "low- and high-amplitude" states will be presented including the effect of adhesion and dissipation.