The CNTs growth by thermal chemical vapor deposition, incorporating a novel plating technique called non-isothermal deposition (NITD) for preparing catalysts on silicon substrate, was investigated in this study. The aim of this research is to examine the effects of particle size and distribution density of Ni catalysts and Ni-Pd co-catalysts on structure morphology of CNTs. The CNTs were grown by thermal chemical vapor deposition (CVD) using C2H2 at various temperatures (ranged from 700 to 900 degrees C). The size and density of Ni catalysts prepared by NITD process were observed to be increased with the increasing deposition time. The diameter and density of the grown CNTs were noted to be increased with the increasing of the Ni catalyst particle size. The results also proved that using Ni-Pd as a co-catalyst had the effect on reducing the growth temperature for the synthesis of CNTs. (c) 2005 Elsevier B.V. All rights reserved.