STM morphology study of ropes of single-wall carbon nanotubes

Abstract

Scanning tunneling microscopy has been performed on ropes of single-wall carbon nanotubes (SWNTs) under ambient conditions. Results show that ropes are generally polycrystalline with grain size ranging from less than 10 nm to more than 100 nm and typical grain size between 10 and 20 nm. Grains remain distinct over the entire rope length. A study of rope shapes reveals that their cross section is not circular. A histogram of the width-to-height ratio presents a marked peak at three with a long tail extending up to twenty. Bundles of SWNTs often have a ribbon-like rather than a rope-like shape.