Synthesis of Multiwall Boron Nitride (BN) Nanotubes by a PVD Method Based on Vapor-Liquid-Solid Growth.

Multiwall boron nitride (BN) nanotubes were synthesized by a novel physical vapor deposition (PVD) method, in which the BN nanotubes grow on a compact substrate composed of AlN, γ-AlO, YO, and carbon powders. The obtained BN nanotubes assemble in an orderly manner with a typical length of over one millimeter and a diameter of one-hundred nanometers. The hollow multiwall tubes have a spherical tip, which is presumed to be a liquid drop at the synthesis temperature, indicating the vapor-liquid-solid (VLS) growth mechanism.