Synthesis of hexagonal monocrystal AlN microtubes and nanowires at low temperature

This paper reports that pure hexagonal aluminium nitride microtubes and nanowires growing along the 0001 direction have been successfully synthesized by directly reacting AlCl_3 with NaN_3 at low temperature (450℃) under condition of non-solvent system. The grey--white powder of reacting product was characterized by high-resolution transmission electron microscope (HRTEM), which shows that the powder is long straight-wire morphology with outer diameter from 40 nm to 300 nm and length up to several micrometres. The results of both electron diffraction (ED) and x-ray diffraction (XRD) indicate that the AlN microtubes have a pure hexagonal monocrystal tubular structure with the combination of the curled AlN nanobelts. Room-temperature photoluminescence spectrum of the synthesized sample showed an emission peak, which is closely related to the small size of the microtubes.