Deep level related yellow luminescence in p-type GaN grown by MBE on (0001) sapphire[Molecular Beam Epitaxy]
Yellow luminescence (YL) has been studied in GaN:Mg doped with Mg concentrations ranging from 10{sup 19} to 10{sup 21} cm{sup {minus}3} by spectral CL (T = 5K) and TEM and explained by suggesting that a different mechanism could be responsible for the YL in p-type GaN with respect to that acting in n-type GaN. Transitions at 2.2, 2.8, 3.27, 3.21, and 3.44 eV were found. In addition to the wurtzite phase, TEM showed a different amount of the cubic phase in the samples. Nano tubes with a density of 3x10{sup 9} cm{sup {minus}2} were also observed by approaching the layer/substrate interface. Besides this, coherent inclusions were found with a diameter in the nm range and a volume fraction of about 1%. The 2.2 eV yellow band, not present in low doped samples, increased by increasing the Mg concentration. It was ascribed to a transition between a deep donor level at 0.8--1.1 eV below the CB edge due to N{sub Ga} and the shallow acceptor due to Mg{sub Ga}. This assumption was checked by studying the role of C in Mg compensation. CL spectra from a sample with high C content showed transitions between a C-related 200 meV shallow donor and a deep donor level at about 0.9--1.1 eV below the CB due to a N{sub Ga}-V{sub N} complex. In their hypothesis this should induce a decrease of the integrated intensity in both the 2.2 and 2.8 eV bands, as actually shown by CL investigations.
- Research Organization:
- CNR-MASPEC Inst., Fontanini-Parma (IT)
- OSTI ID:
- 20104617
- 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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