Abstract
Multiwalled carbon nanotubes were grown vertically on catalytic nanoparticles(Fe、Co、Ni、Fe0.8Co0.2) through the thermal chemical vapor deposition process by pyrolyzing of acetylene and with the mixture of argon(90%)/hydrogen(10%) in the temperature range of 700-900 ℃. The nanoparticles were formed uniformly on the Si/SiO2 substrates after heat treatment of the catalytic films which were pre-deposited by DC sputter on the substrates. High-density aligned carbon nanotubes (CNTs) were synthesized on the iron (Fe) film and the cobalt (Co) film in this work. It was found that the average length and the average diameter of the fabricated CNTs were in the range of 20-50μm and 10-30 nm, respectively. The height of the nanotubes array can be controlled by the deposition period and the processing parameters such as the flow rate of acetylene, pressure, temperature, and the condition of electric field. Images of scanning electron microscopy revealed that the CNT film formed after deposition for 1-5 minutes. This work demonstrated that the area of synthesized CNTs array can extend over several cm2. Moreover, verticality of CNTs on Si and SiO2 substrates are compared and the mechanisms are discussed.