Growth of Carbon Nanotubes on Carbon/Cobalt Films with Different sp 2 /sp 3 Ratios

The need of barrier layer such as SiO 2 for carbon nanotubes (CNTs) growth limits their performance in electronic applications. In this study, conductive carbon/metal (carbon/cobalt—C:Co) composite films with the same metal content, but different sp 2 /sp 3 ratios, were deposited using dual‐source filtered cathodic vacuum arc (FCVA) technique. Three different C:Co composite films were deposited at different temperatures; visible Raman spectroscopy indicates that the sp 2 ‐rich C:Co composite film forms at high temperature (500°C), and high‐resolution transmission electron microscopy (HRTEM) shows the formation of conducting graphitic‐like sp 2 clusters and with Co nanoclusters embedded within them. Electrical measurement shows a significant decrease in film resistivity as sp 2 /sp 3 ratio increases. CNTs were successfully grown on the composite films by plasma‐enhanced vapor deposition (PECVD) approach. Scanning electron microscopy (SEM) shows minor effect on the density of CNTs by varying the sp 2 /sp 3 ratio. The dependence of defect level of the as‐grown CNTs is found to reduce as sp 2 /sp 3 ratio increases.