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\du) 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.