Low-temperature photoluminescence (PL) and optically detected magnetic resonance (ODMR) at 24 GHz have been performed on a series of MBE-grown Mg-doped (1017-1020 cm-3) GaN homoepitaxial layers. High-resolution PL at 5 K revealed intense bandedge emission with narrow linewidths (0.2-0.4 meV) attributed to annihilation of excitons bound to shallow Mg acceptors. In contrast to many previous reports for GaN heteroepitaxial layers doped with [Mg]>3×1018 cm-3, the only visible PL observed was strong shallow donor-shallow acceptor recombination with zero phonon line at 3.27 eV. Most notably, ODMR on this emission from a sample doped with [Mg] of 1×1017 cm-3 revealed the first evidence for the highly anisotropic g-tensor (g∥∼2.19, g⊥∼0) expected for Mg shallow acceptors in wurtzite GaN. This result is attributed to the much reduced dislocation densities (≤5×106 cm-3) and Mg impurity concentrations compared to those characteristic of the more conventional investigated Mg-doped GaN heteroepitaxial layers.
- III-Nitrides and compounds
- Magnetic resonance
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering