This paper examines the field emission synthesis of multi-walled carbon nanotubes (MWCNTs) grown on various interlayers on carbon cloth (CC) substrates, such as Ni/CC, Ni/Ti/CC, and Ni/Al/CC, by thermal chemical vapor deposition using ethylene (C2H4) as the carbon source and nickel (Ni) as the catalyst. The Al interlayer activates the substrate for MWCNTs growth on carbon cloth with Ni as the active catalyst. Field emission SEM was utilized to study the morphology of the catalyst and MWCNTs, and a Raman spectrometer was used to characterize the quality of CNTs. As a result, catalyst particles initiate the nanotube growth and the tube diameters were found to be governed by the size of the associated particles. In our experiment, the smallest size and highest density of catalyst nanoparticles was formed on Al/CC substrate, so that the MWCNTs have a smaller diameter and higher density on this than on Ni/CC and Ni/Ti/CC substrate. Therefore, MWCNTs grown on flexible carbon cloth with an Al interlayer have the best quality and field emission characteristics of the materials examined in this paper.
Department of Mechanical Engineering, National Kaohsiung University of Applied Science, Kaohsiung, Taiwan.