Tunable assembly of carbon nanospheres on single-walled carbon nanotubes

We have developed a process for spontaneous assembly of carbon nanospheres on aligned or nonaligned single-walled carbon nanotubes (SWNTs) by virtue of plasma-enhanced chemical vapor deposition (PECVD). The formation of carbon nanospheres with a uniform size of 30-60 nm is a catalyst-free process and strongly dependent on the applied plasma power and other factors. Both co-deposition and post-deposition approaches have been developed for effective assembly of carbon nanospheres on SWNTs. Furthermore, the method developed here also allows us to tailor the density and size of carbon nanospheres along nanotubes in a controllable way. The heterojunction structure based on different types of carbon demonstrated in this study represents a new hybrid manner for building complex systems which are promising for various applications.