Deep levels introduced in n-GaN grown by the ELOG technique by high-energyelectron irradiation

We have used deep level transient spectroscopy (DLTS) to investigate the el ectron trap defects introduced in n-GaN grown, using the epitaxial lateral overgrowth technique during high-energy electron irradiation from a Sr-90 r adionuclide source. The results indicate that, apart from the major defect with an energy level at 0.20 eV below the conduction band (supposed to be r elated to the V,), at least four other defects with energy levels centered about 0.90 +/- 0.15 eV, are introduced. From modeling, ignoring temperature dependent capture cross-section effects we have determined their activatio n energies, and temperature independent capture cross sections, commonly kn own as the DLTS signature. (C) 2001 Elsevier Science B.V. All rights reserv ed.