Self-organised hybrid nanostructures composed of the array of vertically aligned carbon nanotubes and planar graphene multi-layer

The hybrid carbon nanostructures composed of an array of vertically aligned carbon nanotubes (CNTs) and a self-organised planar graphene multi-layer (PGL) located at the top of the array (CNT-PGL nanostructures) have been obtained by the floating catalyst CVD method. The growth mechanism of CNT-PGL nanostructures is analysed. The fundamental characteristics (morphology, elemental composition and structure) of these nanostructures were characterised by Scanning and Transmission Electron Microscopy, Atomic Force Microscopy, Energy-Dispersive X-ray (EDX), Auger and Raman spectroscopy. It has been established that PGL grows by the typical epitaxial growth of multi-layer films and CNTs grow simultaneously both via root-growth mechanism (attached to the substrate) and tip-growth mechanism (attached to the planar layer). This planar layer is a layered-graphitic structure 'graphene multi-layer' and is connected with CNTs through the catalyst nanoparticles. It consists of disordered graphitic flakes with a size of several tens of nanometres randomly oriented and overlapping one another. These flakes have a crystallite grain of about 5.2 nm in size.