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O: Fachverband Oberflächenphysik

O 101: Scanning Probe Techniques: AFM

O 101.1: Vortrag

Freitag, 20. März 2015, 10:30–10:45, MA 144

Probing higher force gradients with Atomic Force Microscopy on the graphene surface — •Daniel Meuer, Thomas Hofmann, Alfred John Weymouth, Andrea Donarini, and Franz Josef Giessibl — Universität Regensburg, D-93053 Regensburg

Graphene is a very important material for applications in the future, because of its outstanding material properties. The atomic structure of graphite, graphene and carbo-nanostructures were investigated by Scanning Tunneling Microscopy [1] and with Atomic Force Microscopy [2] in several studies.

In this contribution we analyze the higher harmonics of the cantilever oscillation. The signal of the nth harmonic of the cantilever deflection connects to the nth force gradient [3]. Our hypothesis is that the strong signal is a signature of the two top carbon layers that abruptly rehybridize from sp2 to sp3 by forming and breaking a covalent bond between the graphene layer and the buffer layer beneath.

[1] G. Binnig, et al., Europhysics Lett. (EPL) 1, S. 31-36 (1986); S.-I. Park et al., App. Phys. Lett. 48, S. 112 (1986); D. Tománek et al., Phys. Rev. B 35, S. 7790-7793 (1987);

[2] H. Hölscher, et al., Phys. Rev. B 62, S. 6967-6970 (2000); S. Hembacher et al., Proc. of the Nat. Academy of Sciences 100, S. 12539-42 (2003);

[3] U. Dürig, N. J. Phys. 2, 5.1-5.12 (2000); S. Hembacher, et al., Science 305, 380 (2004)