The evolution of the morphology and of the associated extended defects, in thin films grown on sapphire by metal-organic chemical vapor deposition, was shown to depend strongly upon the growth environment. In the case of the 2-step growth process, a change in a growth parameter such as the reactor pressure affected the initial high-temperature growth mechanism. Transmission electron microscopic, atomic force microscopic and high-resolution X-ray diffraction results showed that the initial density of high-temperature islands on the nucleation layer, and the threading dislocation density, could be directly controlled by tailoring the initial high-temperature growth conditions.

The Effect of Growth Environment on the Morphological and Extended Defect Evolution in GaN Grown by Metalorganic Chemical Vapor Deposition. P.Fini, X.Wu, E.J.Tarsa, Y.Golan, V.Srikant, S.Keller, S.P.Denbaars, J.S.Speck: Japanese Journal of Applied Physics - 1, 1998, 37[8], 4460-6