Fabrication of GaN nanowires by ammoniating Ga2O3/Al2O3 thin films deposited on Si(111) with radio frequency magnetron sputtering

GaN nanowires were synthesized by ammoniating Ga2O3/Al2O3 thin films deposited on Si(111) with radio frequency magnetron sputtering. The cylindrical structures were as long as several micrometres, with diameters ranging between 5 and 40 nm. X-ray diffraction (XRD, Rigaku D/max-rB Cu Kalpha), scanning electronic microscope (SEM, HitachiH-8010) and high-resolution TEM (HRTEM) results show that most of the GaN nanowires have a single-crystal hexagonal wurtzite structure with major axis [001] alignment. A minority of them are polycrystalline, composed of micrograms with different growth orientations.