Deposition of carbon nanotubes by capillary-type atmospheric pressure PECVD

In this study, the growth behavior of carbon nanotubes(CNT) deposited from C2H2 by an atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD) method was investigated. The deposition was performed at 400 °C using a modified dielectric barrier discharge using He/C2H2 with additive gases such as N2 and NH3. The effect of the pretreatment on the surface morphology of the Ni catalyst was also investigated. Treatment of the Ni catalyst surface with a He (6 slm)/NH3 (90 sccm) atmospheric pressure plasma for 5 min at 400 °C transformed the Ni surface into more uniformly agglomerated small Ni particles required for the enhanced carbon diffusion during the CNT formation. The CNTs grown by using He (6 slm)/C2H2 (90 sccm) AP-PECVD with additive gases (NH3, N2) for 5 min at 400 °C after the pretreatment showed uniform 1.5–2 μm long and 20–50 nm diameter multi-layer CNTs. By the application of − 1.2 kV of dc bias to the substrate during the growth CNTs by the AP-PECVD, more vertical CNTs could be obtained. FT-Raman data showed the grown CNTs are muti-wall CNTs and have the intensity ratio of D-band/G-band was 0.8–0.9, so defects were involved in the grown CNTs. This study provides a new method growing CNTs at atmospheric pressure and at low temperature, which has special advantages for large scale applications using conventional glass substrates.