SOME NEW FUNDAMENTAL PROPERTIES OF GAN SINGLE-CRYSTAL FILMS ON SIC AND SAPPHIRE SUBSTRATES

The reflectance spectra of GaN/6H-SiC films and the absorption spectra of GaN/Al2O3 films were studied and several fundumental parameters of GaN-energy positions of exciton resonances omega(0), damping constant s Gamma, longitudinal-transverse splittings omega(LT) and the oscillat or strengths f of the exciton states were determined. A blue shift and broadening of the luminescence band were observed in the luminescence spectra of GaN quantum dots. The mean dot radius in the sample was es timated to be about 4.5 nm.