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O: Fachverband Oberflächenphysik

O 40: Methods: Scanning probe techniques I

O 40.1: Vortrag

Mittwoch, 25. März 2009, 15:00–15:15, SCH A316

Detection of charges using scanning force microscopy in contact mode* — •Florian Johann, Akos Hoffmann, and Elisabeth Soergel — Institute of Physics, University of Bonn, Wegelerstr. 8, 53115 Bonn, Germany

Electrostatic force microscopy is the standard technique to detect surface charges using a scanning force microscope (SFM). Therefore the SFM is operated in non-contact mode with an alternating voltage applied to the tip. The electrostatic interaction between the tip and the charges to be measured lead to oscillations of the cantilever that can be read-out using a lock-in amplifier. Now, operating the SFM in contact-mode results in the same electrostatic interaction between tip and surface charges. However, in this case, the tip can not move freely due to its being in contact with the sample surface. To still allow for charge detection in contact-mode, e.g. a deformation of the sample surface underneath the tip caused by the electrostatic forces must occur. To reveal the limits of charge detection in contact-mode SFM we performed a detailed analysis of the relevant parameters such as cantilever stiffness, tip load, and elastic properties of the sample.

*Financial support from the Deutsche Telekom AG is gratefully acknowledged.