Atomic structure and field evaporation of carbon nanotube studied by atom probe field ion microscopy

Using atom probe field ion microscopy (APFIM), the structure of the apex of single-walled carbon nanotube (SWCNT) and multi-walled carbon nanotube (MWCNT) has been studied. By analyzing the FIM image, it became possible to identify the chirality and conductivity of SWCNT. However, a clear FIM image was not successfully obtained for MWCNT due possibly to the difference in heights of each graphene wall. AP of FIM images showed that ions of carbon clusters, such as C₁₄+, C₁₅+, C₁₈+ and C₂₀+, were field evaporated from SWCNT and MWCNT. Since all of these carbon clusters may include a pentagonal plane, it is considered that, under high electric field, a hexagonal plane of graphene reconstructed into pentagonal plane and consequently these clusters field evaporated by the local concentration of electric field at the protruded pentagonal plane.