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Journal of Nanomaterials
Volume 2009 (2009), Article ID 762016, 5 pages
http://dx.doi.org/10.1155/2009/762016
Research Article

Intermittent-Contact Heterodyne Force Microscopy

Laboratory of Nanotechnology, University of Castilla-La Mancha, Plaza Manuel de Meca 1, 13400 Almadén, Spain

Received 9 December 2008; Accepted 26 January 2009

Academic Editor: Min Xu

Copyright © 2009 M. Teresa Cuberes. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Heterodyne Force Microscopy opens up a way to monitor nanoscale events with high temporal sensitivity from the quasistatic cantilever mechanical-diode response taking advantage of the beat effect. Here, a novel heterodyne ultrasonic force method is proposed, in which the cantilever is driven in amplitude-modulation mode, at its fundamental flexural eigenmode. Ultrasonic vibration in the megahertz range is additionally input at the tip-sample contact from the cantilever base and from the back of the sample. The ultrasonic frequencies are chosen in such a way that their difference is coincident with the second cantilever eigenmode. In the presence of ultrasound, cantilever vibration at the difference frequency is detected. Similarly as in heterodyne force microscopy, it is expected that the phase response yields information with increased sensitivity due to the beat effect.