Carbon nanotubes have been grown on alumina-supported iron compound catalysts by 2.45 GHz microwave plasma chemical vapour deposition, without additional substrate heating, using methane/argon gas mixtures with no added hydrogen, and with microwave powers typically up to 100 W. The conditions that produced a stable plasma were investigated by statistical selection of the values of power, pressure and gas flow rates. The conditions for abundant multi-walled nanotube formation were determined within this parameter space by SEM and TEM observations of the deposited material. The temperatures of the plasma and of the substrate in the reactor were investigated by optical emission spectroscopy and melting point samples, respectively. © 2002 Elsevier Science B.V. All rights reserved.
- Chemical vapour deposition