Synthesis, structure and optical properties of GaN nanocrystals prepared by sequential ion implantation in dielectrics

GaN nanocrystals (in the wurtzite phase) were synthesized by sequential implantation of Ga and N ions, either crystalline or amorphous dielectrics, followed by annealing of the samples in flowing NH3 gas at 900 degreesC. A blue shift of the near band-edge photoluminescence (quantum confinement effect) is observed for GaN nanocrystals with a size of similar to2-3 nm, formed in the alpha -Al2O3 substrate.