Eutectic limit for the growth of carbon nanotubes from a thin iron film by chemical vapor deposition of cyclohexane

Carbon nanotubes are grown from a nanometer thin iron film as catalyst by chemical vapor deposition of cyclohexane. We observe growth of carbon nanotubes in a temperature window between 720 and 845 °C. The low synthesis temperature of 720 °C results from the catalyst thickness which lowers the iron–carbon eutectic temperature as compared to bulk iron. At this temperature very little amorphous carbon is deposited on the substrate due to the absence of self pyrolysis of cyclohexane. This points out the importance of the interplay between catalyst thickness and carbon source. The synthesized nanotubes are investigated by resonance Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy.