Characterization of the donor-acceptor-pair transition in nitrogen-implanted zinc oxide

Zinc oxide bulk crystals were doped with nitrogen by ion beam implantation. After postimplantation annealing, a luminescent transition appears at 3.230 eV. Power-dependent photoluminescence studies and time-resolved measurements at several spectral positions within this band can be described by a model for donor-acceptor-pair (DAP) transitions. By tracing the luminescence in a temperature-dependent study, a connection to phonon replicas could be excluded. Based on these results, this luminescence line could be clearly assigned to a DAP transition. In order to increase the doping efficiency, various approaches are considered and discussed. A slight increase could be obtained by high-temperature implantation without postimplantation annealing. (c) 2008 American Institute of Physics.