Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 15: Postersitzung (Adsorption an Oberfl
ächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Rastersondentechniken, Zeitaufgelöste Spektroskopie, Methoden)

O 15.55: Poster

Freitag, 4. März 2005, 17:00–20:00, Poster TU D

Testing SFM-Cantilevers in the Ultra-High Vacuum — •Heiner Lindemann, Lutz Tröger, Sebastian Gritschneder, and Michael Reichling — Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, D-49076 Osnabrück

For taking high-resolution images with a dynamic scanning force microscope (SFM) operated in the so-called non-contact mode, cantilevers with a high Q-factor (about 100.000) are required, i.e. the response function should exhibit a very narrow peak. When detecting the oscillation with a light source operating in the infrared (λ ∼ 800nm or higher), it is essential to use reflex-coated cantilevers as in this wavelength region the material of the cantilever (silicon) is nearly transparent. The reflex-coating, however, decreases the effective Q of the cantilever.
To determine the Q-factor before installing the cantilever into the SFM, cantilevers are tested in a separate ultra-high vacuum (UHV). We designed a setup where cantilevers of different SFM types can be fixed to measure the response function. We describe the design of the test station including a laser light source, a four-quadrants-photodiode and electronics to detect the oscillation of the cantilever that is exited by a piezo ceramic and present testing results obtained with various types of cantilevers.