Luminescence of epitaxial GaN laterally overgrown on (0001) sapphire substrate: Spectroscopic characterization and dislocation contrasts

Photoluminescence and cathodoluminescence spectra are recorded on epitaxial GaN laterally overgrown on (0001) sapphire. Photon recycling, which influe nces the position of the near band edge transition, is evidenced in cathodo luminescence (CL) spectra by changing the accelerating voltage. CL monochro matic images recorded at different wavelengths show that dislocations act a s efficient nonradiative recombination centers, and that they are not respo nsible for the yellow band. (C) 2001 American Institute of Physics.