Graphite nanofibers and multi-wall carbon nanotubes were analyzed using a scanning atom probe. Various clusters of carbon and hydrogen were detected in multi-walled carbon nanotubes. These were mainly H+, H2+, C+, CH3+ and C2H5+. Few cluster ions were detected for the mass range of 100 to 300. The largest mass peak was C28H4+, with two satellite mass peaks. The abundance of the satellites agreed well with the expected abundances of 12C2713CH4 and 12C2613C2H4: 28 and 4%, respectively. No H+ mass peak was found for graphite nanofibers, but significant numbers of ions such as C2H5+, C3H7+ and C4H9+ were detected. These ions were detected at the beginning of mass analysis. After removal of the surface layer, the detection rate of the largest cluster, C23H2, increased. The proposed structure of the C28H4 cluster was a rectangle formed of three rows by three rows of hexagonal cells. That of C23H2 was a triangular arrangement of six hexagonal cells. Four carbon atoms of C28H4 and two carbon atoms of C23H2 clusters were terminated by hydrogen.

Scanning Atom Probe Study of Carbon Nanotubes and Graphite Nanofibers with Hydrogen Terminated Defects. O.Nishikawa, M.Taniguchi, M.Ushirozawa: Journal of Physics - Conference Series, 2008, 100[5], 052084