Properties of the main Mg-related acceptors in GaN from optical and structural studies
- Department of Physics, Chemistry and Biology, Linköping University, S-581 83 Linköping (Sweden)
- Department of Electrical and Computer Engineering and Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)
- Department of Electrical Engineering and Computer Science, Nagoya University, Chikusa-ku, Nagoya, 464-8603 (Japan)
- Department of Materials Science and Engineering, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya 468-8502 (Japan)
The luminescent properties of Mg-doped GaN have recently received particular attention, e.g., in the light of new theoretical calculations, where the deep 2.9 eV luminescence band was suggested to be the main optical signature of the substitutional Mg{sub Ga} acceptor, thus, having a rather large binding energy and a strong phonon coupling in optical transitions. We present new experimental data on homoepitaxial Mg-doped layers, which together with the previous collection of data give an improved experimental picture of the various luminescence features in Mg-doped GaN. In n-type GaN with moderate Mg doping (<10{sup 18} cm{sup −3}), the 3.466 eV ABE1 acceptor bound exciton and the associated 3.27 eV donor-acceptor pair (DAP) band are the only strong photoluminescence (PL) signals at 2 K, and are identified as related to the substitutional Mg acceptor with a binding energy of 0.225 ± 0.005 eV, and with a moderate phonon coupling strength. Interaction between basal plane stacking faults (BSFs) and Mg acceptors is suggested to give rise to a second deeper Mg acceptor species, with optical signatures ABE2 at 3.455 eV and a corresponding weak and broad DAP peak at about 3.15 eV. The 2.9 eV PL band has been ascribed to many different processes in the literature. It might be correlated with another deep level having a low concentration, only prominent at high Mg doping in material grown by the Metal Organic Chemical Vapor Deposition technique. The origin of the low temperature metastability of the Mg-related luminescence observed by many authors is here reinterpreted and explained as related to a separate non-radiative metastable deep level defect, i.e., not the Mg{sub Ga} acceptor.
- OSTI ID:
- 22278154
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Polytype transition of N-face GaN:Mg from wurtzite to zinc-blende
Carbon complexes in highly C-doped GaN