The Effect of Pressure on the Dimensions of Carbon Nanotubes Obtained by the Chemical Vapour Deposition

Carbon nanotubes were synthesized by decomposing ferrocene at 800 °C while investigating the effect of the pressure and flow rate of argon gas on their yield. Thermal decomposition of ferrocene provides both catalytic particles and a carbon source for carbon nanotubes growth. Results showed that a pressure up to 1 bar in conjunction with a temperature higher than 800 °C was favourable for obtaining nanotubes up to ∼40 μm long with diameter ∼20–25 nm. The X ray diffraction pattern shows that they are well crystallized, having hexagonal graphitic nature and showed no evidence of amorphous carbon. Raman spectroscopy was used for the determination of the type of carbon nanotubes, as well as the presence of the defects in the collected soot. Radial breathing mode in Raman spectroscopy clearly indicates the presence of single wall carbon nanotubes in the collected soot. The surface morphology and structure of these carbon nanotubes was revealed by scanning and transmission electron microscopy.