Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 15: Methods: Scanning Probe Techniques II
O 15.4: Vortrag
Montag, 26. März 2007, 15:00–15:15, H41
Optimum excitation and detection of cantilever oscillations in vacuum — •Jannis Lübbe1, Stefan Torbrügge1, Sebastian Gritschneder1, Lutz Tröger1, Holger Schnieder1, Toyoaki Eguchi2, Yukio Hasegawa2, and Michael Reichling1 — 1Fachbereich Physik, Universität Osnabrück, 49076 Osnabrück, Barbarastraße 7, Germany — 2Institute for Solid State Physics, Tokyo University, 5-1-5, Kashiwa, Chiba 277-8581, Japan
The atomic resolution imaging performance of a dynamic scanning force microscope in the ultra-high vacuum critically depends on several technical parameters related to the excitation and detection of the cantilever oscillation. We designed a testing stage allowing the easy insertion and removal of a set of twelve commercial standard cantilevers for quality control prior to measurements. Resonance curves are taken by excitation of a piezo stage with a variable frequency oscillator and detection with a Lock-In amplifier. The Detection of the cantilever motion is based on a deflected laser beam coupled into the vacuum by an optical fibre and focused by an in-vacuo lens. As a laser source we use a current and temperature stabilised low noise laser diode. For low noise detection of the cantilever deflection signal, an in-vacuum quadrant detector connected to a home-built pre-amplifier was used. The detection sensitivity of this set-up and commercially available SFM set-ups used in our group are measured by analysing the thermally excited vibration of the cantilever and noise in the vicinity of the cantilever with a Fourier analyser.