Influence of InGaN interlayer thickness on GaN layers grown by metal organic chemical vapour deposition

InGaN interlayer was grown between GaN layers on sapphire substrate using metal organic chemical vapour deposition. The crystalline quality of the sample was investigated using high-resolution X-ray diffraction. The indium composition and InGaN thickness were determined to be 10–15% and 5–10 nm, respectively. Transmission electron microscopy image revealed the interfacial characteristics of the InGaN and GaN layers. Raman spectroscopy revealed prominent GaN peak positions with InGaN shoulder peaks. The growth mode of InGaN and GaN was determined as nanoislands with helical-like morphology by atomic force microscopy. Hall measurement showcased improvement in the mobility and bulk concentration for the GaN/InGaN (5 nm)/GaN structures.