Epitaxial layers of cubic GaN were grown by metal-organic vapor-phase epitaxy, with Si-doping carrier concentrations ranging from 3 x 1018 to 2.4 x 1020/cm3. It was found that Si-doping decreased the yellow emission from GaN. However, heavy doping of n-type material was found to induce a phase transformation. As the Si-doping concentration increased, the number of hexagonal GaN nanoparticles increased. As judged from the line-widths in X-ray rocking curves, Si-doping increased the density of dislocations and stacking faults. On the basis of the observations, a model was proposed in order to explain phase transformations which were induced by generated micro-defects such as dislocations and precipitates, and induced stacking faults after heavy Si-doping.

Effect of Si Doping on Cubic GaN Films Grown on GaAs(100). D.Xu, H.Yang, J.B.Li, S.F.Li, Y.T.Wang, D.G.Zhao, R.H.Wu: Journal of Crystal Growth, 1999, 206[1-2], 150-4