Strained layer growth of Ga In P on GaAs 100/ and 1yx x GaP 100/ substrates

We have investigated by Reflection High Energy Electron Diffraction RHEED.the relaxation of strained Ga1yxInxP layers grown by Gas Source Molecular Beam Epitaxy GSMBE.on GaAs 100.and GaP 100.substrates. We show that for tensile layers grown on GaAs at 5208C, the 2D–3D growth mode transition occurs around 3–4 monolayers ML.when the In content reaches 30%, i.e. for a lattice mismatch of 1.4%. This abnormal behavior is not observed when compressive layers are grown on GaP at 5208C for the same mismatch magnitude. We discuss this difference taking into account the composition and temperature ranges for which spinodal decomposition of Ga1yxInxP alloys have been predicted together with the strain sign. q2000 Elsevier Science B.V. All rights reserved