On the evolution of GaInAs/GaAs strained epitaxial layers

Abstract
We find that in a highly lattice-mismatched heteroepitaxial growth, as critical thickness is reached, defects are formed within a thin layer at the surface and do not necessarily propagate to the interface. At that thin layer the strain is locally decreased resulting in a larger lattice parameter, which persists until the next step takes place. This procedure is inferred from the Raman scattering data of InxGa1−xAs/GaAs. Disorder induced Raman spectroscopy in a scattering forbidden configuration is shown to be an extremely sensitive tool for observing this stepwise release of the strain.