In the study, metal seed layers (gold and nickel) of different thicknesses were deposited onto a substrate via electron beam evaporation prior to growth. The films de-wet on the surface to form localized seeds at elevated temperatures, and act as preferential nucleation sites for GaN nanowires. The rate of nucleation events and probability of defect formation is governed by the supersaturation and surface energies of the seeds.

The team found that gold-seeded GaN nanowires grow slower compared with nickel-seeded ones, and also contain 2D defects that are seldom found in nickel-seeded GaN nanowires. The optical properties of the final material were also observed to differ as a result of the nanowire growth rate and substrate effects. These phenomena are all closely tied to the fraction of gallium atoms in the seed particles during nanowire growth.

Full details can be found in the journal Nanotechnology.