Nanocrystals at MBE-grown GaNrGaAs 001/ interfaces

Molecular beam epitaxy MBE.growth utilising an RF-plasma nitrogen source was used to study surface reconstruction and the effects of nitridation damage on the surface and interface morphology of GaN on GaAs 001.at 5808C. Keeping both the N-flow and plasma excitation power constant, the grown layers were studied with the Ga-flux as a parameter. In the initial growth stage, a 3=3.surface reconstruction was observed. Samples grown under N-rich, Ga-rich and stoichiometric conditions were characterised by high-resolution scanning electron microscopy SEM.and atomic force microscopy AFM. to reveal the surface morphology. The nitridation damage was characterised by Auger-electron spectroscopy AES., X-ray diffraction XRD.spectroscopy and high-resolution SEM, which revealed separated GaN and GaAs phases at interfaces deeply in the substrate region, bordered by 1014 and 1114 facets. The defect formation at the GaNrGaAs interface depended on the NrGa-flux ratio. q2000 Elsevier Science B.V. All rights reserved.