Synthesis of AlN hexagonal bipyramids by carbothermal reduction nitridation

•Wurtzite-structured aluminum nitride (AlN) hexagonal bipyramids were prepared.•The preferred growth direction of the AlN hexagonal bipyramids is [0001].•The AlN hexagonal bipyramids showed near-band edge emission at 512 nm.

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 Fe2O3, SiO2 and Na2O 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.