Characterisation of surface morphological defects in MBE-grown GaN As layers on GaAs

Layers of GaN0.1As0.9 were grown by molecular beam epitaxy MBE.on GaAs 001.. By high-resolution scanning electron microscopy SEM., 3–4 mm surface defects were observed in 4-mm-thick layers. Their origin is a combination of nitrogen reaction with the substrate and the lattice mismatch. These defects had a conical shape and their walls consisted of GaN nano-crystallites with solved arsenic as detected by Auger-electron spectroscopy AES.. q2000 Elsevier Science B.V. All rights reserved.