Synthesis and growth mechanism of aluminum nitride nanowires via a chloride-assisted chemical vapor reaction method

We report a large scaled fabrication of AlN nanowires via a chloride-assisted chemical vapor reaction technique at 1100?°C in flowing N₂ atmosphere using aluminum powders as starting materials. The as-obtained hexagonal AlN nanowires had the length of hundreds of microns and diameter of 20–100?nm, and indicated a single crystalline characteristic. The yield production was significantly increased with ammonium chloride and aluminum chloride addition because of the formation of intermediate gaseous AlCl and HCl. The addition of ammonium chloride and aluminum chloride also promoted the formation of ferric chloride, which served as the catalyst and further facilitated the growth of AlN nanowires. The vapor–liquid–solid and vapor–solid growth mechanism are proposed and discussed in details.