Growth of high-quality GaN on (100) Ga2O3 substrates by facet-controlled MOVPE

Abstract We report a comprehensive study of the growth of GaN layers on (100)-oriented Ga2O3 substrates by metalorganic vapour phase epitaxy (MOVPE), especially the improvement on using an intermediate facet-control layer between the low-temperature buffer and the high-temperature GaN layer compared to the usual two-step growth process. We examined in detail the effects of substrate nitridation, carrier gas, and variation of the thickness of the low-temperature buffer GaN layer, and the thickness and growth temperature of the facet layer. This optimization allowed us to obtain GaN layers on (100)-oriented Ga2O3 with high structural and optical quality, as shown by high-resolution x-ray diffraction, electron microscopy, optical absorption, and luminescence measurements.