Heterogeneous growth of BCN nanotubes by laser ablation

Multi-wall nanotubes have been synthesized by metal catalyzed laser ablation of a BN and carbon composite target in a tube furnace heated to 1000°C or 1200°C and flowing with nitrogen gas. The products are characterized by scanning transmission electron microscopy and electron energy-loss spectroscopy. No single-wall nanotube has been found in the products. Thinner nanotubes with a few layers are usually composed of pure carbon. CCN layers exist at the outer surface of thicker nanotubes. The layer number and chemical composition vary along the tube axis. The growth mechanism of the heterogeneous nanotubes is discussed.