The yellow luminescence band in high-energy 7 MeV electron-irradiated n-GaN is investigated as a function of electron irradiation dose. Both the yellow-band intensity and the near-bandedge photoluminescence (PL) intensity decrease continually with increasing electron irradiation dose. The decrease rate for the yellow-band intensity is less compared to the near-bandedge intensity; however, it is found that the ratio of the yellow-band intensity to the near-bandedge PL intensity increases with increasing electron irradiation dose. To interpret this phenomenon. a theoretical model is developed for the yellow-to-near-bandedge intensity ratio based on rate equations. The proposed model is in good agreement with the experimental observation. The electron spin resonance (ESR) and light-induced ESR (LESR) spectra are measured to investigate deep defects induced by electron irradiation. The ESR signal intensity at g = 1.9451 decreases with increasing electron irradiation dose and increases with the light-induced time. (C) 2001 Elsevier Science B.V. All rights reserved.