Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 48: Scanning Probe Methods I

O 48.11: Vortrag

Mittwoch, 2. April 2014, 13:00–13:15, GER 38

Investigations on the imaging dynamics of carbon nanotube based probes in intermittent-contact AFM — •Moid Bhatti — Institut für Experimentalphysik, Universität des Saarlandes, 66041 Saarbrücken, 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) or nanowires (NW) can fulfill this requirement motivating an understanding of their interaction with the sample.

We are studying contact mechanics of the cantilever-sample system in the dynamic mode AFM using: (1) nanowires (NW) grown on a substrate whose dynamic behavior is equivalent to an AFM cantilever with a NW attached to it (AFM-NW), (2) carbon nanotubes (CNT) attached to an AFM cantilever (AFM-CNT), and (3) focused-ion-beam-(FIB)-structured NC (AFM-NC).

Single-walled AFM-CNT have been in use as a super tip. A CNT adds to the complexity of the contact mechanics of the probe-sample system because it can stick, slip, adhere, kink, and buckle as it interacts with the sample surface leading to imaging artifacts. We describe here the imaging dynamics of AFM-NW by using a long and shortened multi-walled CNT and explain the interaction dynamics using cantilever trajectories, distance-dependent resonance curves, and amplitude-distance curves which differ from those of the conventional AFM tips in a marked way.