Nitrogen ions were implanted into melt-grown ZnO (0001) Substrates and subsequently annealed at 800 degrees C Under all oxygen ambient. The photoluminescence spectrum of N+-implanted ZnO excited by a He-Cd laser exhibited donor-acceptor pair (DAP) transition emission at 385 nm with a full width at half maximum of 30 nm at 10 K. The DAP emission is associated with the acceptor energy of nitrogen in ZnO, calculated to be 170 meV. Defect-related red emission at about 610 nm observed in N+-implanted ZnO was due to the residual damage from the implantation step because it was also observed in Ar+-implanted ZnO but not in un-implanted ZnO annealed at 800 degrees C under the same oxygen ambient. (C) 2009 Elsevier Ltd. All rights reserved.
