The morphology, structure, and optical properties of gallium nitride nanowires grown using metal-organic chemical vapour deposition on r-plane sapphire using gold and nickel seed particles were investigated. It was found that different seed particles resulted in different growth rates and densities of structural defects in metal-organic chemical vapour deposition-grown GaN nanowires. Ni-seeded GaN nanowires grew faster than Au-seeded ones, and they did not contain the basal plane stacking faults that were observed in Au-seeded GaN nanowires. It was proposed that stacking-fault formation was related to the supersaturation and surface energies in different types of seed particles. Room temperature photoluminescence studies revealed a blue-shifted peak in Au-seeded GaN nanowires compared to the GaN near-bandgap emission. The blue-shifted peak evolved as a function of the growth time and originated from the nanowire base, likely due to strain and Al diffusion from the substrate. The results demonstrated that the seed-particle composition had a direct impact upon the growth, structure, and optical properties of GaN nanowires and revealed some general requirements for seed particle selection for the growth of compound semiconductor nanowires.

Using Seed Particle Composition to Control Structural and Optical Properties of GaN Nanowires. X.Zhou, J.Chesin, S.Crawford, S.Gradečak: Nanotechnology, 2012, 23[28], 285603