Field ion microscopy of multiwall carbon nanotubes: observation of pentagons and cap breakage under high electric field

Abstract

Field ion microscopy (FIM) study of multiwall carbon nanotubes (MWCNTs) was carried out, and carbon pentagons located at the tip of a capped MWCNT were observed with atomic resolution. Changes of structures of MWCNT tips, which were brought about by field evaporation of carbon during the FIM experiment, were also observed. A MWCNT emitter initially gave FIM images originating from extruded pentagons on its tip, but finally gave ring patterns. The final ring patterns were the same as those from open MWCNTs obtained by oxidation process.