Growth of carbon nanotubes using low pressure chemical vapour deposition

A low pressure chemical vapour deposition method is employed to fabricate iron catalysed carbon nanotubes. The iron catalyst is deposited on silicon substrate using a thermal evaporation method. The reactive gas mixture is C2H2/H2 with a flow rate of 50/50 sccm. The chamber pressure and temperature are maintained at 5 torr and 800°C respectively. The growth time is fixed at 15 minutes. It is evident from the SEM images of these carbon nanotubes that their diameter varies from 20 nm to 50 nm and the length of these nanotubes is of the order of several microns. TEM images suggest that these nanotubes are multi-walled and show an ordinary structure of carbon nanotubes. The growth mechanism of these nanotubes is also discussed.