Highly ordered nanostructures of single crystalline GaN nanowires in anodic alumina membranes

Synthesis of highly ordered nanostructures of single crystalline GaN nanowires in anodic alumina membranes was achieved through a gas reaction of Ga2O vapor with a constant ammonia atmosphere at 1000°C in the presence of nano-sized metallic indium catalysis. Atomic force microscopy, X-ray diffraction, Raman backscattering spectrum, scanning electron microscopy, and transmission electron microscopy indicate that the ordered nanostructure consists of the single crystalline hexagonal wurtzite GaN nanowires with about 20 nm in diameter and 40∼50 μm in length in the uniform nanochannels of the anodic alumina membrane. The vapor–liquid–solid (VLS) growth mechanism of the ordered nanostructure was discussed in detail.