We report spatially resolved photoluminescence (PL) and micro-Raman scattering studies of epitaxial lateral overgrowth (ELO) of GaN on a SiO2 -masked sapphire substrate. Near-field scanning optical microscope measurements show that the ELO layers exhibit strong band-edge emission and yellow-band emission. Raman spectra reveal E2 (low) and E2 (high) phonon modes at ∼143 and ∼569 cm-1, respectively. Interestingly, the E2 (high) phonon intensity is significantly increased in the ELO layers. Furthermore, minima of the spectral widths of this mode occur in the ELO layers. The E2 (low) phonon mode exhibits similar behavior, that is, its intensity is stronger in ELO GaN on SiO 2 stripes than in coherently grown GaN on the mask openings. PL and Raman results suggest that crystalline quality is enhanced and threading dislocation density is reduced in the ELO layers.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2010 Jun 21|
ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials