Scanning tunneling microscopy observation of coiled aluminum nitride nanotubes

We report the first observations of AlN nanotubes in twisted and helicoidal arrangements, with clear indications of hexagonal atomic arrangement. The AlN nanotubes, synthesized by gas phase condensation using solid–vapor equilibrium, were dispersed on a highly oriented pyrolitic graphite substrate and analyzed by Scanning Tunneling Microscopy. The origin of the coil formation is thought to arise from the high level of stress, that occurs during growth, which is caused by the high rate of collisions and high temperature. Finally, I–V curves show that, such AlN nanotubes are metallic in character.