Investigation of Optical and Structural Properties of GaN Grown by Hydride Vapor-Phase Epitaxy

Abstract

Photoluminescence and reflectance experiments of high quality GaN layers grown by hydride vapor-phase epitaxy reveal narrow (2-3 meV) free and bound exciton transitions. Quenching of three acceptor-bound exciton peaks is observed with increasing film thickness (3.5-400 μm). Changes in the PL features appear to be independent of the impurity concentrations, as measured by secondary ion mass spectrometry, and the dislocation densities, obtained by photo-enhanced chemical etching. Therefore, the observed acceptor levels are assigned to intrinsic defects originating from the substrate/layer interface and decreasing in density with the thickness of the film.