Properties of GaN layers grown on N-face free-standing GaN substrates

• GaN layers were homoepitaxially MOCVD grown on N-face free-standing substrates.
• A high-quality smooth layer was obtained with optimized growth process.
• Epilayers have improved donor-bound exciton recombination time.

GaN layers were homoepitaxially grown on N-face free-standing GaN substrates using a hot-wall metalorganic chemical vapor deposition method. By using optimized growth parameters, layers with a smooth morphology were obtained. The crystalline quality of epilayers was studied by a high resolution X-ray diffraction technique and compared to the substrates. Optical properties of the epilayers studied by low temperature time-resolved photoluminescence have shown longer recombination time for donor-bound exciton compared to the substrates.