Abstract
We report on the synthesis and elemental mapping of ropes composed of aligned multi-walled B–C–N nanotubes using energy-filtered (Omega filter) high-resolution transmission electron microscopy. The nanotube ropes were synthesized by reacting aligned
CN
x
(x⩽0.1)
nanotubes with B
2O
3 in a N
2 atmosphere at 1985–2113 K. It was found that the overall B–N content within the ropes increases with temperature. Furthermore, BN-rich tubular ropes obtained at higher synthesis temperatures exhibit complex shell assembly: BN-rich, C-rich and B–C–N layers were found to exist. The latter nanostructure represents a unique `nanocable' with either conducting or semiconducting shells shielded with insulating BN-rich layers. We envisage that the novel nanocables will also exhibit high-oxidation resistance at elevated temperatures.