High-Quality InGaN Films Grown on GaN Films

InGaN films were grown on GaN films with a high indium source flow rate and high growth temperatures between 780°C and 830°C. Strong and sharp band-edge (BE) emissions between 400 nm and 445 nm were observed, while deep-level emissions were barely observed in photoluminescence (PL) measurements at room temperature. The full width at half-maximum (FWHM) of the BE emissions was about 70 meV. The FWHM of the double-crystal X-ray rocking curve (XRC) from the InGaN films was about 8 minutes. This value of FWHM was the smallest one ever reported for InGaN films, and was almost the same as that of the GaN films which were used as the substrate.