ROLE OF TE ON THE MORPHOLOGY OF INAS SELF-ASSEMBLED ISLANDS

The effect of Te presence on the morphology and distribution of InAs i slands grown by molecular beam epitaxy on GaAs is investigated. Atomic force microscopy was used to follow the dependence of height, radius, and surface density on Te and InAs coverages. They ranged from zero t o 0.45 monolayers (ML) of Te, and from 1.8 to 3.5 ML for InAs. We obta ined a higher density of islands for samples covered with 0.3 ML of Te . The number of islands is essentially the same for samples covered wi th 0 and 0.45 hit of Te. A delay on the onset of island growth is obse rved for samples with theta(Te) = 0.45 ML. The surface morphology is a lso different for samples with Te when compared with the Te free sampl e. We suggest that for theta(Te) = 0.45 ML the coherence-incoherence t ransition is either delayed or absent for the InAs coverage range stud ied. (C) 1998 American Vacuum Society.