One-step fabrication of high quality double-walled carbon nanotube thin films by a chemical vapor deposition process

High-quality double-walled carbon nanotubes (DWCNTs) thin-films have been fabricated in one-step by the catalytic chemical vapor deposition gas-flow reaction process with acetone as a carbon source in an argon flow. The DWCNTs film is formed through the self-assembly of the DWCNTs in the gas flow, which is achieved by controlling the gas rates in the synthesis reaction. The DWCNT film is self-supported and consists of preferentially aligned high-quality DWCNT bundles. Raman spectral analysis shows a low intensity ratio of the D band and the G band with I_D/I_G being 0.025 indicating a high-quality of DWCNTs at a macroscopic scale. Property measurements show that the DWCNT film is mechanically robust and highly electrically conductive. The formation of high-quality DWCNTs can be attributed to the reaction in the argon environment that is inert and does not attack the DWCNTs at the high synthesis temperature (1170 °C). This one-step fabrication process is feasible for large-scale productions of high-quality DWCNTs films with promising structural and functional applications.