Synthesis of AlN hexagonal bipyramids by carbothermal reduction nitridation

Wurtzite-structured aluminum nitride (AlN) hexagonal bipyramids were prepared via a carbothermal reduction nitridation method using alumina and carbon as the raw materials. The growth of the AlN hexagonal bipyramids is dominated by the vapor-solid (VS) mechanism with Fe 2 O 3 , SiO 2 and Na 2 O acting as mineralizers under alternate gas pressures. The preferred growth direction of the AlN hexagonal bipyramids is [0001]. Photoluminescence spectra of the AlN hexagonal bipyramids showed near-band edge emission at 512   nm at room temperature. The AlN hexagonal bipyramids might be useful for optical micro-devices.