Excitonic emissions from hexagonal GaN epitaxial layers

Excitonic photoluminescence (PL) peaks from hexagonal GaN epilayers were investigated making a connection with the analysis of the photoreflectance spectra. Free exciton emissions associated with transitions from the conduction (Gamma(7c)) band to the A (Gamma(9v)) and B (Gamma(7uv)) valence bands are dominant above 100 K. Values of the full widths at half maximum of them were smaller than the thermal energy k(B)T up to room temperature, which suggests the dominance of excitons in the PL spectra. (C) 1996 American Institute of Physics.