Photoluminescence of a ‐plane GaN: comparison between MOCVD and HVPE grown layers

We report on the emission properties of nonpolar a ‐plane GaN layers grown by metalorganic chemical vapor deposition (MOCVD) and hydride vapor phase epitaxy (HVPE). Together with the typical band edge exciton emission, the low‐temperature photoluminescence spectra reveal several emission bands in the spectral range 3.29‐3.42 eV. These emissions appear with different intensities in layers grown by different techniques and show different thermal quenching and recombination dynamics. The 3.42 eV and 3.35 eV emissions are found to be of an intrinsic origin and are associated with carriers localized at stacking faults. The emission at 3.29 eV, which is present only in MOCVD layers, shows a donor‐acceptor pair behavior suggesting that impurities attached to structural defects are involved. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)