Theoretical studies on one-dimensional AlN nanostructures have been performed. A faceted instead of cylindric model is proposed to reasonably understand the synthesized hexagonal AlN nanotubes. The close correlation is established that the nanotube structure should possess similar symmetry to that of the corresponding bulk crystal. This is also suitable for the few other faceted nanotubes and could be used to predict the morphology for the increasing nanotubes from nonlayered materials.
