Browsing by Subject "Tip"

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    Construction of a scanning tunneling microscope and first results
    (1990) Oral, Ahmet
    In this thesis, construction of a Scanning Tunneling Microscope in air is explained. A step motor sample approach mechanism and a tripod scanner are used in the construction. Atomic resolution images of graphite samples are obtained in both constant current and constant height modes. Loss of trigonal symmetry in some Graphite images are also observed. This anomaly is attributed to the multiple atom tip or slipped top layer of Graphite.
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    Quantitative atom-resolved force gradient imaging using non contact-AFM/STM
    (American Institute of Physics, 2001) Oral, A.; Grimble, R. A.; Ozer, H. O.; Hoffman, P. M.; Pethica, J. B.
    Quantitative force gradient images are obtained using a sub-angstrom amplitude, off-resonance lever oscillation method during scanning tunneling microscopy imaging. We report the direct observation of short-range bonds, and the measured short-range force interaction agrees well in magnitude and length scale with theoretical predictions for single bonds. Atomic resolution is shown to be associated with the presence of a prominent short-range contribution to the total force interaction. It is shown that the background longer-range interaction, whose relative magnitude depends on the tip structure, has a significant effect on the contrast observed at the atomic scale. (C) 2001 American Institute of Physics.