Optical, structural investigations and band-gap bowing parameter of GaInN alloys

We have performed a detailed investigation of the photoluminescence features taken at 2 K on a series of Ga x In 1− x N alloys grown by metal-organic vapour-phase epitaxy through the whole composition range. The evolution of the photoluminescence lineshape of GaInN alloys in the indium-rich region is dominated by doping effects rather than by band-gap tailing effects correlated to existence of random chemical crystal inhomogeneities. The lineshape of the photoluminescence indicates a residual electron concentration of about 10 18–10 19 cm −3 in the bulk part of the epilayers. The value we get for the bowing parameter is b=2.8 eV.