Properties of InGaN layers grown on sapphire substrates by MOCVD

InGaN films of various compositions grown by MOCVD (Metallorganic chemical vapor deposition) using PL (photoluminescence), Hall and SEM techniques were analysed. When the V/III ratio is equal to 5000, the temperature of 750 °C is suitable for the growth of InGaN samples. Under these specific conditions, the electron concentration is about 2.21×10 18 cm -3 and the In content is about 11.54%. The wavelength of the near band-gap edge peak is 394 nm at 295 K and its full width of half maximum (FWHM) is about 116 meV. According to the relations between the wavelength and the intensity of the near-band-gap-edge peak, at the growth temperature of 750 °C, the temperature coefficient of the InGaN sample is 0.56×10 -3 V/K and the binding energy of the near-band-gap-edge peak is 32.4 meV. At higher growth temperatures (800°C and 900°C), the In content and the PL intensity of InGaN sample will decrease. The metal particles of In can be observed on the surface of the sample.