Irradiation-induced phase transformations in carbon nanostructures

Structural phase transformations from multi-walled carbon nanotubes to amorphous carbon nanowires by carbon ion irradiation are experimentally carried out. A volume expansion effect during the formation of amorphous carbon nanowires is observed by an in situ TEM measurement. Moreover, the transformation of carbon nanotubes to nanocrystalline diamond is performed by hydrogen plasma post-treatment of carbon nanotubes. More importantly, diamond nanorods can be obtained by prolonging the treatment time of hydrogen plasma. Different sputtering yields for different carbon allotropes under hydrogen plasma treatment are responsible for the formation of diamond nanorods. (C) 2004 Elsevier B.V. All rights reserved.