Compositional and morphological analysis of InxGa1-xN/GaN epilayers

The compositional and surface morphological properties of InxGa1-xN epilaye rs with different indium content grown on GaN sublayers have been studied b y x-ray diffraction (XRD), RES, XPS and atomic force microscopy (AFM), The InxGa1-xN epilayers were grown on GaN by metal-organic chemical vapour depo sition. Reliable x values, ranging from 0.10 +/- 0.01 to 0.22 +/- 0.01, wer e determined by complementary XRD and RES investigations, and no bulk phase segregation was found by XRD, The thickness of InxGa1-xN epilayers was det ermined by RES to be between 70 and 260 nm, In contrast to the lack of phas e segregation of InxGa1-xN in the bulk, surface In-Ga alloy species were de tected by XPS even at low indium content (x similar to 10%), and the amount of this species increases with indium content, Indium content was also fou nd by AFM to have a significant influence on the surface morphologies of In xGa1-xN. The surface root-mean-square roughness increased from 0.82 mm at x = 0.10 to 9.0 mm at x = 0.23, Copyright (C) 1999 John Wiley & Sons, Ltd.