Room-temperature diluted magnetic semiconductors p-(Ga,Ni)N

High concentration (5at.%) Ni was incorporated into a chemical vapor deposition-grown GaN film by using a thin protecting Ni layer on top of the GaN film during ion implantation. After etching off the protecting layer, subsequent annealing up to 800°C under flowing N₂ resulted in a p-type GaN with  apparent ferromagnetic behavior up to ∼320K. In addition, the ferromagnetic behavior became more manifest with increasing annealing temperature that increases hole concentration. No presence of any other second phases nor clusters in the Ni-implanted region was identifiable, at least to the 0.2nm0.2nm point-to-point resolution of high resolution transmission electron microscopy. This novel indirect implatation process that being easy to implement appears promising for attaining room-temperature diluted magnetic semiconductors which are applicable to magnetotransport, magneto-optical and spintronics devices, among others.