Of catalyst supporting layer on carbon nanotubes growth

Due to their extraordinary electrical, thermal and mechanical properties, carbon nanotubes have been foreseen as potential materials for electronics devices in the future. To integrate carbon nanotubes in electronic applications, carbon nanotubes would need to be grown on different metal layer. In this study, carbon nanotubes growth with Ni as catalyst on three different support layers, Cu, Al and Cr, by hot filament chemical vapor deposition (HFCVD) is reported. The nanotubes were grown using C ₂H ₂ acetylene as carbon feedstock, in a hydrogen and nitrogen atmosphere. The catalyst layers and their support layers were deposited by magnetron sputtering technique. Deposited films were annealed at 600°C for 10 minutes before exposing to C ₂H ₂ for the growth of nanotubes at same temperature for another 10 minutes. The effects of the support layer have been investigated with reference to nanotubes formation. The morphology and microstructure of the films were measured and analyzed by scanning electron microscopy (SEM) and Raman spectrometer. It was found that reaction of the catalyst with its supporting layer has significant effects on the growth of nanotubes. For Cu or Cr as support layer, its effect on the nanotubes growth was minimal. However Al support layer prevented the growth of carbon nanotubes. The possible mechanisms for the observed results are proposed.