Synthesis Of Aligned Carbon Nanotube Films By CVD Method

Growth of aligned carbon nanotube films were studied by the catalytic pyrolysis of C₂H₂ over the iron salt coated quartz and ceramic substrates and by chemical vapor pyrolysis reactions via the solvent injection of liquid hydrocarbons dispersed with ferrocene. By using xylene as the carbon source and optimizing the reaction conditions, including the growth temperature, the concentration of catalyst, the flow rate of carry gases, aligned multi-wall carbon nanotube (MWNT) films of 150μm in thickness were grown on quartz substrates in H₂ and Ar/H₂ flow by the single injection of xylene dispersed with ferrocene. The double injection process, comparing to the other processes, are technically simple, avoiding the use of the toxic gases (ammonia) and the hydrocarbons (pyridine), which provides a safer and controllable way to synthesize well aligned CNTs arrays. By using ethanol as the carbon source and using ethylenediamine as the nitrogen source, the bamboo nanotube arrays were obtained in a wide synthesis window between 850°C and 950°C, and at the ratio ethylenediamine/ethanol in the range of 0.1 and 0.5 at 1000 sccm Ar.