1. Optical and electrical properties of GaN: Si-based microstructures with a wide range of doping levels
- Author
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Vadim A. Shalygin, N.G. Filisofov, Lauri Riuttanen, A. Yu. Serov, G. A. Melentyev, Sami Suihkonen, Olli Svensk, Leonid E. Vorobjev, L.A. Shelukhin, V. F. Agekyan, Henri Nykänen, and E. V. Borisov
- Subjects
Materials science ,Photoluminescence ,Silicon ,Condensed matter physics ,Band gap ,business.industry ,Exciton ,Doping ,Physics::Optics ,chemistry.chemical_element ,Gallium nitride ,Condensed Matter Physics ,Epitaxy ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Condensed Matter::Superconductivity ,symbols ,Optoelectronics ,business ,Raman spectroscopy - Abstract
The optical and electrical properties of silicon-doped epitaxial gallium nitride layers grown on sapphire have been studied. The studies have been performed over a wide range of silicon concentrations on each side of the Mott transition. The critical concentrations of Si atoms corresponding to the formation of an impurity band in gallium nitride (∼2.5 × 1018 cm−3) and to the overlap of the impurity band with the conduction band (∼2 × 1019 cm−3) have been refined. The maximum of the photoluminescence spectrum shifts nonmonotonically with increasing doping level. This shift is determined by two factors: (1) an increase in the exchange interaction leading to a decrease in the energy gap width and (2) a change in the radiation mechanism as the donor concentration increases. The temperature dependence of the exciton luminescence with participating optical phonons has been studied. The energies of phonon-plasmon modes in GaN: Si layers with different silicon concentrations have been measured using Raman spectroscopy.
- Published
- 2015