Optically detected magnetic resonance of shallow donor - shallow acceptor and deep (2.8-3.2 eV) recombination from Mg-doped GaN

Comprehensive photoluminescence (PL) and optically detected magnetic resonance (ODMR) experiments have been performed on a set of GaN epitaxial layers doped with Mg from 2.5 x 10(18) to 5.0 x 10(19) cm(-3). Strong shallow donor-shallow acceptor recombination at 3.27 eV is observed from the lowest-doped sample while broad emission bands at 2.8 and 3.2 eV were found from the more heavily doped films. ODMR at 24 GHz on these bands reveals evidence for effective-mass shallow donors and Mg-related accepters with unique g-tensors, including the first observation of the resonance parameters (g(parallel to) = 2.113(4) and g(perpendicular to) = 1.970(5)) associated with Mg shallow accepters in GaN. (C) 1999 Elsevier Science B.V. All rights reserved.