Electron-beam irradiated GaN n(+)-p diodes were characterized by deep level transient spectroscopy (DLTS) and optical responsivity measurements. The GaN n(+)-p diode structures were grown by metal organic chemical vapor deposition technique, and the electron irradiation was done by the energies of 1 MeV and 2 MeV with dose of 1 x 10(16) cm(-2). In DLTS measurement, the defect states of E-c-0.36 eV and E-c-0.44 eV in the electron irradiated diodes appeared newly. The optical responsivity of GaN n(+)-p diode was characterized in ultra-violet region, and then the maximum optical responsivity at 350 nm was decreased after electron-beam irradiation. (C) 2007 Elsevier B.V. All rights reserved.