An intercepted feedback mode for light sensitive spectroscopic measurements in atomic force microscopy
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Updated: Jul 10, 2026

Force Spectroscopy of Single Protein Molecules Using an Atomic Force Microscope
Published on: February 28, 2019
1Institut für Festkörperelektronik, TU-Wien, Floragasse 7, A-1040 Wien, Austria. juergen.smoliner@tuwien.ac.at
Abstract:
In most atomic force microscopes (AFMs), the motion of the tip is detected by the deflection of a laser beam shining onto the cantilever. AFM applications such as scanning capacitance spectroscopy or photocurrent spectroscopy, however, are severely disturbed by the intense stray light of the AFM laser. For this reason, an intercepted feedback method was developed, which allows to switch off the laser temporarily while the feedback loop keeps running. The versatility of this feedback method is demonstrated by measuring tip-force dependent Schottky barrier heights on GaAs samples.
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