Carbon-nanotubes on graphite: alignment of lattice structure

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.