Photocurrent spectroscopy investigations of Mg-related defects levels in p-type GaN
The defect levels associated with Mg impurity in p-type GaN films were systematically investigated in terms of doping concentration by photocurrent spectroscopy. Mg-doped GaN samples were grown on sapphire substrate by metal organic chemical vapor deposition and annealed in nitrogen atmosphere at 850* for 10 minutes. At room temperature, PC spectra showed two peaks at 3.31 and 3.15 eV associated with acceptor levels formed at 300 and 142 meV above valence band in as grown samples. But, after the thermal annealing, PC spectra exhibited various additional peaks depending on the Mg concentration. In the GaN samples with Mg concentration around 6*7 x 10{sup 17} cm{sup {minus}3}, they have observed PC peaks related to Mg at 3.31 as well as 3.02 eV and carbon acceptor at 3.17 eV. For moderately Mg doped GaN samples, i.e., the hole concentration p = 3*4 x 10{sup 17} cm{sup {minus}3}, additional peak was observed at around 0.9 eV which can be attributed to defects related to Ga vacancy. For relatively low Mg doped samples whose hole concentrations are 1*2 x 10{sup 17} cm{sup {minus}3}, additional broad peak was observed at around 1.3 eV. This peak may be related to the yellow band luminescence. As the Mg concentration is increased, the concentration of Ga vacancies can be reduced because Mg occupies the substitutional site of Ga in GaN lattice. When the hole concentration is above 6*7 x 10{sup 17} cm{sup {minus}3}, the yellow luminescence and Ga vacancy related peaks disappeared completely.
- Research Organization:
- Chonbuk National Univ., Chonju (KR)
- OSTI ID:
- 20104641
- Resource Relation:
- Conference: 1999 Materials Research Society Fall Meeting, Boston, MA (US), 11/28/1999--12/03/1999; Other Information: PBD: 2000; Related Information: In: GaN and related alloys -- 1999. Materials Research Society symposium proceedings, Volume 595, by Myers, T.H.; Feenstra, R.M.; Shur, M.S.; Amano, Hiroshi [eds.], [1050] pages.
- Country of Publication:
- United States
- Language:
- English
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