Si-Doped InGaN Films Grown on GaN Films

High-quality Si-doped InGaN films were grown on GaN films for the first time. Strong and sharp band-edge (BE) emissions were observed at peak wavelengths between 400 nm and 425 nm, while deep-level emissions were not observed in photoluminescence (PL) measurements at room temperature. The intensity of BE emissions of Si-doped InGaN films was about 36 times stronger than that of undoped InGaN films and 20 times stronger than that of the blue emission (at 450 nm) of Mg-doped p-type GaN films. The smallest full width at half-maximum (FWHM) of the double-crystal X-ray rocking curve (XRC) from the Si-doped InGaN films was 6.4 minutes. This value of FWHM was the smallest ever reported for InGaN films.