Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter. Our current focus is on detection and sensing/imaging with an emphasis on the development of integrated photonics. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.


Height anomalies in tapping mode atomic force microscopy in air caused by adhesion

(full pdf)

VanNoort SJT, VanderWerf KO, DeGrooth BG, VanHulst NF, Greve J
vol 69 issue 2: p117-p127 SEP 1997

Height anomalies in tapping mode atomic force microscopy (AFM) in air are shown to be caused by adhesion. Depending o­n the damping of the oscillation the height of a sticking surface is reduced compared to less sticking surfaces. It is shown that the height artefacts result from a modulation of oscillatory movement of the cantilever. Damping and excitation of the cantilever by the driver continuously compete. As a consequence a severe modulation of the cantilever oscillation occurs, depending o­n the phase mismatch between the driver and the cantilever. Phase images of tapping a mode AFM show contrast which correlates with adhesion. Examples of a partially removed gold layer o­n mica, a Langmuir-Blodgett film and DNA show height artefacts ranging up to 10 nm.
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