Epitaxialn-GaNwas irradiated with 5.4-MeV He ions. Capacitance–voltage(C–V)measurements showed that 5.4-MeV He ions remove free carriers at a rate of6200±300 cm−1in the first micron below the surface. Deep level transient spectroscopy (DLTS) revealed that, in addition to the radiation-induced defects previously detected by DLTS at 0.18–0.20 eV below the conduction band, He-ion irradiation introduced two additional prominent defects, ER4(EC-0.78 eV)and ER5(EC-0.95 eV)at rates of1510±300and3030±500 cm−1,respectively. Capture cross-section measurements revealed that electron capture kinetics of ER5 is similar to that of a line defect. ©1998 American Institute of Physics.