Evidence of strong nanotube alignment and for iron preferential growth axis in multiwalled carbon nanotube carpets

This letter reports structural results obtained from x-ray scattering measurements performed on individual carbon nanotube carpets. Carpets of aligned multiwalled nanotubes are synthesized by the aerosol pyrolysis method using liquid hydrocarbon/metallocene aerosols. Nanotube alignment of +/-5.5degrees with respect to the average growth axis is obtained. In addition, nanotubes are partially filled with iron, and we demonstrate that the body of the carpet contains mainly one phase (gamma-Fe) encapsulated inside nanotubes which exhibits a preferential crystallographic <110> axis along the nanotubes. (C) 2004 American Institute of Physics.