Simultaneous synthesis of vertically aligned carbon nanotubes and amorphous carbon thin films on stainless steel

Carbonaceous nanostructures such as carbon nanotubes, graphene and transparent carbon-based thin films are envisioned to be part of the next generation of electronic devices, mechanical structures, and energy-storage systems. To synthesize these nanostructures on a large scale by chemical vapor deposition, large-area, flexible substrates are needed. Here, we studied the role of a metallic foil, stainless steel, as a self-catalytic substrate for carbon nanostructure synthesis. As a result, vertically aligned carbon nanotubes and amorphous carbon thin films were simultaneously obtained. We further showed that the evolution of the stainless steel foil during the different steps of the process played a critical role in carbon nanotubes and carbon thin film growth. A better understanding of how the growth of these carbon nanostructures is affected by stainless steel evolution under chemical vapor deposition conditions will enable the synthesis of hybrid carbon nanotubes/amorphous carbon nanostructures and pave the way to scale-up of their low-cost production.