Photoluminescence of nitrogen-doped ZnO

Photoluminescence (PL) of N-doped epitaxial ZnO and N+-implanted bulk ZnO are studied. The N-doped epitaxial ZnO films were grown on GaN templates by plasma-assisted molecular beam epitaxy with a flux of N2 gas was added to the O2 gas flow in the RF plasma source. The N+-implanted bulk ZnO was fabricated using nitrogen ions implanted into a melt-grown ZnO (0001) substrate with subsequent annealing at 800 °C under oxygen ambient. PL spectra of N-doped epitaxial ZnO and N+-implanted bulk ZnO excited by a He-Cd laser exhibit 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, 170 meV. Defect-related red luminescence at about 610 nm observed in N+-implanted ZnO is attributed to the damage due to implantation because it is also observed in P+- or Ar+-implanted bulk ZnO but is not observed in N-doped epitaxial ZnO. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)