Regensburg 2007 – scientific programme

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O: Fachverband Oberflächenphysik

O 17: Poster Session I (Nanostructures at Surfaces; Metal Substrates: Epitaxy and Growth; Methods: Scanning Probe Techniques; Phase Transitions)

O 17.40: Poster

Monday, March 26, 2007, 17:30–20:30, Poster C

Material contrast measurement with a multifrequency AFM — •Maximilian Baumann, Alexander M. Gigler, and Robert W. Stark — CeNS and Crystallography, Dep. Earth and Environmental Sci., Ludwig-Maximilians-Universität München, 80333 München, Germany

Mapping topography and material contrast of a surface simultaneously with a scanning probe microscope is influenced by the crosstalk between the two. To avoid this, we present a new measurement technique, the so called multifrequency approach, as proposed by Rodriguez et al.[1]. In this mode of operation, a conventional AFM in non-contact tapping mode is operated with two different mechanical excitation frequencies, the first and second eigenmode of the cantilever. The first eigenmode is used to map the topography and to maintain close contact with the surface. The second eigenmode allows to determine the phase and amplitude signal with minimal topographical crosstalk. A lock-in amplifier is used to demodulate the signal with respect to the second eigenmode.

[1] T.Rodriguez et al.: Compositional mapping by excitation of the second cantilever mode, Appl.Phys.Letters 84 (3), pp.449-451 (2004).