The dominant electrically active defect produced by 0.42MeV electron irradiation in GaN was a 0.07eV donor. Since only N-sub-lattice displacements could be produced at this energy, and since theory predicted that the N interstitial was a deep acceptor in n-type GaN, it was argued that the 0.07eV donor was most likely the isolated N vacancy. The background shallow donors, in the 0.024 to 0.026eV range, actually decrease in concentration, probably due to interactions with mobile N interstitials that were produced by the irradiation. Thus, the recent assignment of a photoluminescence line as an exciton bound to a 0.025eV N-vacancy donor was incompatible with the results. Moreover, that photoluminescence line was not observed in the sample.

On the Nitrogen Vacancy in GaN. D.C.Look, G.C.Farlow, P.J.Drevinsky, D.F.Bliss, J.R.Sizelove: Applied Physics Letters, 2003, 83[17], 3525-7