Engineering the cap structure of individual carbon nanotubes and corresponding electron field emission characteristics

Electron field emission measurements on individual carbon nanotubes (CNTs) were performed inside a transmission electron microscope. Controlled removal of carbon atoms at the tip of the CNT was realized and various tip structures were fabricated. In particular, a capped CNT was opened and an opened CNT was converted into a capped CNT, and corresponding field emission characteristics were measured. Our results show that the electron field emission properties of CNTs are highly sensitive to the emission tip structures. The ability to modify the tip structure thus provides a way to control the field emission property of the CNT and vice versa.