Non-contact atomic force microscope in ultra high vacuum using radiation pressure excitation of cantilever with Fabry-Perot interferometer

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2017
Karagöz, Ercan
In this study Non-Contact Atomic Force Microscope (NC-AFM) imaging was performed by excitation of the cantilever via radiation pressure in a custom Ultra-High Vacuum (UHV) system. Both the excitation of the cantilever and the measurement of the deflection of the cantilever were done by employing a fiber Fabry-Pérot interferometer obtained by a TiO2 coating of the fiber end. This coating allows for a several times higher interference slope. The second normal mode of the cantilever oscillation, along with the first mode was clearly observed by excitation via radiation pressure without spurious peaks with Fabry-Pérot interferometer for the first time. By comparing the results of the cantilever spring constant measurements obtained by thermal excitation and radiation pressure excitation amplitude modulation, the reliability of the method of excitation by radiation pressure was shown. In order to test the interferometer a highly ordered pyrolytic graphite (HOPG) sample was imaged by exciting the cantilever with piezo-acoustic excitation. Then imaging experiments were carried out for obtaining atomic resolution image of a clean Si(111) (7x7) surface by exciting the cantilever with radiation pressure. 

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Citation Formats
E. Karagöz, “Non-contact atomic force microscope in ultra high vacuum using radiation pressure excitation of cantilever with Fabry-Perot interferometer,” M.S. - Master of Science, Middle East Technical University, 2017.