走査トンネル顕微鏡の分析化学的応用に関する研究

概要

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A new analytical technique which can discriminate surface individual molecules or functional groups within a molecule by a combination of spectroscopic methods such as tunneling spectroscopy or tunneling barrier height (TBH) measurement with scanning tunneling microscopy (STM), was proposed. Development of the measurement system and its application to some sample systems was carried out ; some preliminary results are described. Atomic resolution was achieved as confirmed by STM observation of graphite surface atoms. Atomic-scale molecular images of a liquid crystal 4-cyano-4'-n-heptylbiphenyl (7CB) adsorbed on graphite were also obtained. Spatially resolved current-voltage measurement within a molecule was performed for the first time. The data revealed site dependence within the 7CB molecule. This is the first demonstration of discrimination between functional groups within a molecule based on spectroscopic information. TBH is also expected to be useful for discrimination of molecules or functional groups since it depends on the electronic property of the adsorbed molecule. TBH is also of interest from the viewpoint of the imaging mechanism of adsorbed molecules. TBH imaging revealed atomic-scale spatial distribution at the surface of 7CB/graphite. A comparative study of the profile with STM topography experimentally suggested the possibility of a close relation between them.
社団法人日本分析化学会の論文
1995-01-05