In situ splitting of carbon nanotube bundles with atomic force microscopy

In situ splitting of single-walled carbon nanotube (SWCNT) bundles on the surface of highly oriented pyrolytic graphite was realized using atomic force microscopy (AFM). With an optimal force load of the AFM tip, it was found that the lateral force applied to the nanotube bundle could overcome the adhesive interaction between SWCNTs within the bundle, consequently separating individual nanotubes from the bundle. The threshold of the tip force load for splitting a 'raft' bundle that consists of two SWCNTs was found to be similar to45 nN in our experiments. Our results and analysis show that strong interaction between nanotube bundles and underlying substrate is necessary for the successful splitting of nanotube bundles. This result provides new possibilities for the controllable manipulation of carbon nanotubes.