Felix Loske , Philipp Rahe and Angelika Kühnle
Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49076 Osnabrück, Germany
Felix Loske et al 2009 Nanotechnology 20 264010
Non-contact atomic force microscopy (NC-AFM) was applied to study C60 molecules on rutile TiO2(110). Depending on the tip–sample distance, distinctly different molecular contrasts are observed. Systematically decreasing the tip–sample distance results in contrast inversion that is obtained reproducibly on the C60 islands. This change in contrast can be related to frequency shift versus distance (df(z)) curves at different sample sites, unraveling crossing points in the df(z) curves in the attractive regime. We have performed simulations based on a simple Morse potential, which reproduce the experimental results. This combined experimental and simulation study provides insight into the mechanisms responsible for molecular contrast in NC-AFM imaging. Moreover, this work demonstrates the importance of distance-dependent measurements for unambiguously identifying molecular positions within a molecular island using NC-AFM.
68.37.Ps Atomic force microscopy (AFM)
61.48.-c Structure of fullerenes and related hollow molecular clusters
Issue 26 (1 July 2009)
Received 4 December 2008
,
in final form 16 January 2009
Published 10 June 2009
Felix Loske et al 2009 Nanotechnology 20 264010
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