The nature and control of morphology and the formation of defects in InGaAs epilayers and InAs/GaAs superlattices grown via MBE on GaAs(100)

Initial stages of molecular beam epitaxial (MBE) growth of highly mismatched InxGa1-xAs/GaAs(100) have been studied by planar and cross-sectional transmission electron microscopy. For In0.5Ga0.5As growth, we find drastic differences in morphology obtained by reducing the growth temperature form 475 to 420°C. We also observe differences in morphology between alloy growth and short period superlattice ((InAs)n/(GaAs)m (m = 1 monolayer, n = 2 monolayers) growth of equivalent effective composition. In the case of growth by formation of large islands, we present direct evidence of strain relief at the island edges and discuss defect formation in these islands.