Hetero-epitaxy of InAs on the (2 x 4) and c(4 x 4) reconstructed surfaces of GaAs(001) was studied using scanning tunnelling microscopy, with particular emphasis being placed upon the formation and evolution of the two-dimensional InxGa1−xAs wetting layer. The influence of the initial GaAs reconstruction on the growth behaviour was significant for InAs coverages <0.8ML, but both qualitative (surface morphology and reconstruction) and quantitative (step density) surface characteristics converge for coverages >1ML. The effects of surface reconstruction were only important for sub-ML InAs coverages, with strain effects dominating at higher coverages. scanning tunnelling microscopy topographs indicate a high and rapid disordering of the WL for coverages >0.5ML, implying that strain-driven alloyed WL formation was important even below 1ML. The 2D→3D growth mode transition and the formation of self-assembled quantum dots was delayed at low As fluxes. In this case strain relief occurred first by a reconstruction change from (1 x 3) to a more In-rich (4 x 2) structure, with quantum dot formation taking place only after the deposition of an additional amount of InAs (≈0.2ML).

Wetting Layer Evolution in InAs/GaAs(001) Heteroepitaxy - Effects of Surface Reconstruction and Strain. T.J.Krzyzewski, P.B.Joyce, G.R.Bell, T.S.Jones: Surface Science, 2002, 517[1-3], 8-16