Mg acceptors in GaN: Dependence of the g-anisotropy on the doping concentration

Mg accepters in GaN epitaxial layers grown by metal-organic vapour-phase ep itaxy were investigated by optically detected magnetic resonance (ODMR) spe ctroscopy. The magnetic resonances were detected on the magnetic circular d ichroism (MCD) of the acceptor bound exciton ((MgX)-X-0) in the near bandga p region, and in the infrared spectral range on the MCD of the hole ionisat ion transition Mg-0 + hv --> Mg- + h(VB). The observed g-values of the Mg-0 accepters range for g(parallel to) from 2.102 to 2.065 and for g(perpendic ular to) from 1.94 to 2.00, respectively. These variations depend on the Mg doping concentration. (C) 1999 Elsevier Science B.V. All rights reserved.