Effect of catalyst on growth behavior of carbon nanotube synthesizing by microwave heating thermal chemical vapor deposition process

Abstract

A modified chemical vapor deposition process, which utilizes a susceptor to absorb the microwave and to self generate the heat, for heating up the Si substrate, was used for growing carbon nanotubes (CNTs). The advantage of such a process is that the deposition chamber can be maintained at around room temperature with only the substrates localized heated, such that the deposition temperature can be more precisely controlled. The influence of the pretreatment process for catalyst-coated Si substrates on growth behavior of CNTs and the related electron field emission properties were systematically examined. Among the form of catalyst used, the Fe(NO3)(3)-ethythersilicate mixture performs much better than the de sputtered Fe films. The higher the concentration of Fe species in the catalyst mixture, the denser the CNTs formed on the subs;rates, resulting in better held emission properties. Thus grown CNTs can be turned on at a very low field (E(0)congruent to0.78 V/mum), achieving a very large emission current density (J(e)congruent to 13 mA/cm(2)) at 5.5 V/mum applied field. (C) 2001 American Vacuum Society.