Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 43: Poster Session II - MA 141/144 (Surface Spectroscopy on Kondo Systems; Frontiers of Surface Sensitive Electron Microscopy; Methods: Scanning Probe Techniques+Electronic Structure Theory+Other; Time-Resolved Spectroscopy of Surface Dynamics with EUV and XUV Radiation; joined by SYNF posters)

O 43.9: Poster

Dienstag, 26. Februar 2008, 18:30–19:30, Poster F

Self-actuating self-sensing cantilever for dynamic AFM — •Henning von Allwörden, Alexander Schwarz, C. Julian Chen, and Roland Wiesendanger — Institute of Applied Physics, University of Hamburg, Jungiusstraße 11, 20355 Hamburg

Conventional AFM force sensors consist of a flexible cantilever beam made from silicon. For operation in the dynamic mode they are actuated by a driver piezo. Common methods for detection of the cantilever oscillation are optical techniques like beam deflection or interferometry. Hence, force sensor, its actuation and its detection are three separated devices. Combining them into a single device would make AFM instruments much simpler in design and handling. The qPlus sensor [1] is a tuning fork based on z-cut quartz. One arm is glued to a substrate, the other serves as a cantilever. The cantilever oscillation is detected by utilizing the piezoelectric effect of quartz via a pair of electrodes. However, excitation is still done externally. Furthermore, these sensors have large spring constants, resulting in a low force sensitivity. It is not possible to choose from a large variety of spring constants and resonance frequencies. Our idea is to place two pairs of electrodes, one for actuation and one for detection on a cantilever made from a single piece of x-cut quartz. Hence, we would have a self-actuating self-sensing cantilever [2]. Eigenfrequency and spring constant can be adjusted by choosing appropriate dimensions. The general concept of this sensor will be discussed and properties of prototypes will be presented.

[1] Giessibl, Appl. Phys. Lett. 73, 3956 (1998)

[2] patent pending