Proton bombardment-induced electron traps in epitaxially grown n-GaN

Using deep-level transient spectroscopy, we have studied the electrical properties of defects introduced in epitaxially grown n-GaN during 2-MeV proton bombardment. The main defects detected, ER2 and ER3, are introduced at rates of 400+/-150 and 600+/-100 cm(-1), respectively, and have energy levels at 0.16+/-0.03 and 0.20+/-0.01 eV, respectively, below the conduction band. A less prominent defect, ER1, with an energy level at 0.13+/-0.01 eV below the conduction band, is introduced at a rate of 30+/-10 cm(-1). The small capture cross section of ER3 [(8+/-4) x 10(-18) cm(2)] implies that it is in a neutral or negative state when above the Fermi level. (C) 1999 American Institute of Physics. [S0003-6951(99)03803-6].