Effects of high-energy ball milling on the morphology and the field emission property of multi-walled carbon nanotubes

The effects of grinding time in a vibration mill on the morphology and the field emission property of multi-walled carbon nanotubes (MWNTs) were studied using XRD, Raman spectra and high-resolution transmission electron microscopy (HRTEM). The results show that the closed ends of MWNTs are partly broken when ground for 4 h. The number of broken ends increases with grinding time. The field emission measurement results indicate that the presence of Fe particles can improve the field emission property of ground MWNTs. (C) 2004 Elsevier B.V. All rights reserved.