INFLUENCE OF THE SUBSTRATE TYPES AND TREATMENTS ON CARBON NANOTUBE GROWTH BY CHEMICAL VAPOR DEPOSITION WITH NICKEL CATALYST

Abstract

Our investigation aimed at the development of a process capable of producing well ordered, vertically aligned carbon nanotubes (CNTs) arrays, with reproducible properties, for applications such as a position particle detector and a cold cathode emitter for storage devices. The results on catalyst nanoparticles formation from a thin Ni film evaporated on SiO₂ and Si3N₄ substrates are presented. The substrate-catalyst layers have been processed in several gaseous atmospheres and in the temperature range 700-900°C in order to obtain the most appropriate morphology, size and density of the nanoparticles for the subsequent CNTs growth. The smallest nanoparticles have been obtained on the SiO₂ substrate in H₂ atmosphere and at the lowest temperature 700°C. However, the best vertically aligned and well graphitized CNTs resulted from the NH3 annealing process followed by the deposition of CNTs at 900°C in C₂H₂ and NH₃.