Composite nanostructures based on template-crown boron nitride nanotubules

The fabrication of boron nitride nanotubules and BN-based composite nanostructures within the pores of anodic aluminum oxide is described. Boron nitride nanotubules are produced by pyrolyzing 2,4,6-trichloroborazine over alumina templates at 750 degrees C. The nanotubules are polycrystalline, with crystallites exhibiting an orientational ordering such that the BN (001) planes are tilted 25 degrees with respect to the tube axis. Nanotubules at least 20 mu m long are observed, longer than what is expected for a growth mechanism that assumes a uniform substrate coating. This suggests that tubes grow in the axial direction faster than in the radial direction. As an example of a CVD-fabricated composite nanostructure, we synthesized coaxial C/BN/C nanotubules by the sequential pyrolysis of acetylene and trichloroborazine over alumina templates. BN-insulated copper nanowires were also fabricated by electrochemical deposition of copper into BN-coated templates.