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By means of STM measurements and fully self-consistent transport calculations we analyze how STM trajectories for the mapping of nanostructures on surfaces are affected by the atomic structure of the tip. For the particular case of carbon nanotubes we show that considerable distortions of the STM trajectory with respect to the actual structure, position and diameter of the nanotube can occur for certain tip geometries. Comparison between theory and experiment can allow to characterize and correct these distortions. [ABSTRACT FROM AUTHOR]

We study the alignment of the lattice structure of single walled carbon-nanotubes (SWNT) produced on a highly oriented pyrolytic graphite (HOPG) surface using controlled growth in ultrahigh vacuum (UHV). With scanning tunnelling microscopy (STM) at low temperature ( T=77 K) the HOPG and the SWNT were imaged in UHV simultaneously with atomic resolution. The lattice structure of the SWNT was compared to the HOPG. For this purpose we present a technique for evaluating the mutual orientation which uses the measured lattice vectors of the HOPG surface as a reference for distortion and drift effects in the STM image. The quantitative evaluation showed an alignment of the SWNT lattice structure to the structure of the substrate. [ABSTRACT FROM AUTHOR]