zno film, codoping, photoluminescence, p-type zno, acceptor pair luminescence, molecular-beam epitaxy, light-emitting-diodes, thin-films, donor, dependence, emission, exciton, 0204 Condensed Matter Physics, 0912 Materials Engineering, Applied Physics
Temperature-dependent photoluminescence (PL) from p-type ZnO film codoped with Al and N has been investigated. In the whole temperature range of 10-300 K, the PL was dominated by a broad emission centered at 3.05 eV. The dependencies of its peak energy on temperature and compensation indicate that this emission is due to recombination of localized carriers. We suggest that the localization is due to potential fluctuations caused by strong compensation and local compositional fluctuations of the impurities. We obtain an activation energy of similar to 69 meV from thermal quenching of the luminescence intensity and ascribe it to thermal ionization of shallow donors. (c) 2006 Elsevier Ltd. All rights reserved.