Effects of temperature oscillations on the growth of carbon nanotubes by chemical vapor deposition

We have grown carbon nanotubes at oscillatory growth temperature by chemica l vapor deposition. The high-resolution transmission electron microscopy (H RTEM) images show that they contain a number of incomplete carbon layers bo th on the outer and inner periphery and dislocations in the middle part of the carbon nanotubes walls. The defect structure of these nanotubes depends on the period of the T oscillation. In addition, HRTEM examinations of the se carbon nanotubes from end-on reveal that some have polyhedral sections a nd contain dislocations. These features make them more active chemically an d might have significant influence on the properties and applications of th e carbon nanotubes. (C) 2000 American Institute of Physics. [S0003-6951(00) 01007-X].