Digital Pulsed Force Mode and Dynamical Friction Measurements

•Alexander Gigler1, Peter Spizig2, Stefan Walheim3, Othmar Marti1 und Thomas Schimmel3
1Experimental Physics, University of Ulm, D-89069 Ulm, Germany
2WITec GmbH, www.WITec.de
3Institute for Nanotechnology, Forschungszentrum-Karlsruhe GmbH, D-76021 Karlsruhe, Germany

As a standard technique force vs. distance plots (FD-plots) allow to acquire local mechanical properties, but they are at least two orders of magnitude too slow when used in a surface imaging mode. In order to measure an entire image at the same scanning speed, the Pulsed-Force-Mode was developed. A recent development is the Digital Pulsed Force Mode, that acquires each force curve for every pixel during a single run of the experiment. Therefore, postprocessing algorithms, i.e. for the calculation of the energy dissipated in each cylce, can be used to analyze the sample in various ways without scanning the sample more often and possibly destroying it.

To access friction parameters and the properties accessible by PFM at thesame time, the system has been extended to the COmbined-DYnamical-Mode and is now also capable of dynamical friction measurements. The concurrent measurement of both friction and adhesion is especially important, since both seem to be closely related.

In this poster, the principles of this measurement system, the implementation on our WITec a-SNOM setup and results on a SAM based on a lift-off technique using m-contact printing will be shown.