Ni-catalysed carbon nanotubes and nanofibers assemblies grown on TiN/Si(100) substrates using hot-filaments combined with d.c. plasma CVD

Different carbon nanotubes or nanofibers (CNTs or CNFs) assemblies were obtained using Ni catalyst deposited by Pulsed Laser Deposition (PLD) on TiN/Si(1 0 0) substrate from a H-2/C2H2 mixture using plasma emerging from triode configured electrodes with two pairs of intercalated incandescent filaments at 1 kPa and 700 degrees C. In the presence of a relative intense plasma (54W power), a dense CNT carpet was grown. The TEM images revealed the presence of elongated yet contorted 10-15 nm diameter CNTs with encapsulated Ni particles at their tips. Using a low plasma power (8 W) in similar conditions and from the same catalyst, a different morphology resulted: few self-sustained long fibrils (diameter around 1 mu m) which are curved under the action of their own weight containing compacted CNTs/CNFs and (only in the confined zones near the lateral edges) 50-200 nm thick filaments presenting bud-like structures and Y-shape junctions. (C) 2012 Elsevier B.V. All rights reserved.