Catalytic hydride vapour phase epitaxy growth of GaN nanowires

Catalytic growth of GaN nanowires by hydride vapour phase epitaxy is demonstrated. Nickel-gold was used as a catalyst. Nanowire growth was limited to areas patterned with catalyst. Characterization of the nanowires with transmission electron microscopy, x-ray diffraction, and low temperature photoluminescence shows that the nanowires are stoichiometric 2H-GaN single crystals growing in the [0001] orientation when grown on sapphire, with occasional stacking faults along the c-axis as the only defect type observed in most of the wires. A red shift observed in the photoluminescence was too large to be explained by the minor strain observed alone, and was only marginally affected by temperature, suggesting a superposition of several factors.