Low temperature, non-isothermal growth of carbon nanotubes

Non-isothermal growth of carbon nanotubes (CNTs) was studied in order to obtain the activation energy. CNTs were grown on an Fe–Si catalyst using microwave plasma-enhanced chemical vapor deposition of CH4. During the growth, the substrate was heated by the plasma such that its temperature increased with the growth until equilibrium was reached. In other words, the CNT growth took place under simultaneously increased time and temperature. This has resulted in different growth kinetics from previously published studies. We have therefore examined the growth kinetics using an empirical function for CNTs grown on three different substrates and derived the relevant activation energies based on the empirical function.