A chemical method has been developed for synthesizing boron nitride nanowires through the reaction of a mixture gas of nitrogen (N2) and ammonia (NH3) over nanoscale a-FeB particles at 1100℃. Boron content in the product comes from the a-FeB catalyst itself. Transmission electron microscopic image indicates an abundant quantity of BN nanowires with diameter about 20nm and length up to several tens of microns. The product has also been characterized by high-resolution electron microscopy and electron energy loss spectrometer. The perfectly straight lattice fringes with an interlayer spacing of about 0.333nm corresponding to d0002 spacing of h-BN indicate that the BN nanowires are well crystallized. Also, a growth mechanism has been speculated.

Gallium phosphide nanotubes with zinc blende structure were synthesized for the first time. The as-prepared GaP nanotubes are polycrystalline with diameters of 30-120nm and occasionally partially filled. The growth has been reasonably proposed to follow vapor-liquid-solid (VLS) mechanism. The integration of the nanotubular structure with the unique intrinsic semiconducting properties of GaP might bring GaP nanotubes some novel optical and electronic properties and applications.

A possible smallest single-walled BN nanotube with the diameter of 0.4nm is proposed. The studied nanotube is of armchair (3,3) and thought to be associated with the BN fullerene, B12N12. We have applied the ab initio MP2/6-31G//HF/6-31G method to investigate the growth mechanisms of this nanotube from B12N12. Our results show that a B12N12 fullerene may react with B2H6 and NH3 to form an armchair (3,3) tubular structure under certain experimental conditions such as high temperature. The armchair (3,3) tube can continuously incorporate B and N atoms to grow and can also disassociate H2 to close into a half-B12N12 cap. The growth of the tube is predicted to be favorable to the capping of the tube in an atmosphere with B2H6 and NH3 in it. And the cap of the tube is relatively easier to be opened by H2 or B2H6 and NH3 to convert to a growing open-ended tube.

Periodic spindle-unit boron nitride (BN) nanotubes with buglelike open-end tips have been found in the product by nitriding Fe-B nanoparticles at 1100℃ with a mixture of nitrogen and ammonia gas. The microstructure was well-characterized by high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDX). The diameter of this BN nanotube shows a decreasing tendency along the growth direction. For each spindle unit, the outer diameter decreases steeply and then increases gradually, accompanied by thinning of the wall thickness along the growth direction. Some spindle units are partially occupied by the iron-containing catalyst particles at the hemispherical-like ends. An improved stress-induced sequential growth model has been reasonably deduced accordingly, with which the formation process of this novel BN nanostructure could be well understood.