Growth and microstructure of AlN whiskers and dendrites

AlN whiskers or dendrites were synthesized with asublimation-recrystallization method by using Al, AlN powders and some additives as raw materials.Whiskers with different sizes that featured high purity and good crystallinity were obtained by controlling temperature and gas supersaturation in the reaction container. The whiskers were described as long and straight single crystals of approximately 1-30 μm in diameter by the centimeter range in length. However, AlN dendrites were about 1mm in diameter by 0.5cm in length,and showed an obviously preferential growth orientation, i.e., perpendicular to2111 and1011 planes. It is concluded that the whiskers or dendrites grow via the vapor-solidmechanism.