Prospective optical properties were demonstrated for nearly stacking fault-free m-plane GaN homoepitaxial films grown by metal organic vapor phase epitaxy onto m-plane free-standing GaN substrates. The full-widths at half-maximum of the X-ray rocking curves were close to the substrate values; being 31arcsec for (10•0) diffraction with <00•1> azimuth and 48arcsec for (10•2) diffraction. The threading dislocation densities were lower than 5 x 106/cm2. The film surfaces exhibited an atomically flat morphology, with well-aligned monolayer steps. The low-temperature photoluminescence spectra exhibited polarization-dependent well-resolved bound and free exciton emission lines, and a characteristic polarized photoluminescence line was observed. The room-temperature photoluminescence lifetime of the free exciton peak increased with the ammonia/trimethylgallium ratio, and a record m-plane GaN value of 268ps was found.

Optical Properties of Nearly Stacking-Fault-Free m-Plane GaN Homoepitaxial Films Grown by Metal Organic Vapor Phase Epitaxy on Low Defect Density Freestanding GaN Substrates. S.F.Chichibu, H.Yamaguchi, L.Zhao, M.Kubota, K.Okamoto, H.Ohta: Applied Physics Letters, 2008, 92[9], 091912