Growth of carbon nanotubes on carbon/cobalt films with different sp2/sp3 ratios

• Main Authors: Xu, Naiyun, Tsang, Siu Hong, Tay, Beng Kang, Teo, Edwin Hang Tong, Ng, Chee Mang
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Materials::Nanostructured materials
• Online Access: https://hdl.handle.net/10356/101533; http://hdl.handle.net/10220/18663
• Institution: Nanyang Technological University

The need of barrier layer such as SiO2 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 sp2/sp3 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 sp2-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 sp2 clusters and with Co nanoclusters embedded within them. Electrical measurement shows a significant decrease in film resistivity as sp2/sp3 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 sp2/sp3 ratio. The dependence of defect level of the as-grown CNTs is found to reduce as sp2/sp3 ratio increases.