Carbon nanofiber or carbon nanotube? - The role of hydrogen during rapid thermal processing

Carbon nanotube coatings were synthesized by rapid thermal processing of nickel doped amorphous carbon films. During sputter deposition of the films, different ratios of hydrogen/argon gas were used to study the effect of hydrogen on carbon nanotube growth. The results showed only amorphous nanofibers were grown on unhydrogenated films, while the hydrogenated films yield multiwalled carbon nanotubes. Hydrogen is believed to promote catalytic life of the nickel catalyst dots as well as gasifying the inner amorphous core of the nanofibers so as to result in the formation of the nano tubular structures.