Strain-induced modulation versus superlattice ordering in epitaxial (GaIn)P layers

One main goal of the present work was to perform specific metal-organic vapor-phase epitaxy experiments to prove existing models for the fundamental process of superlattice ordering in the model system (GaIn)P. Applying a modulated-growth regime, we prepared (GaIn)P/GaAs multilayers, which enabled us to follow the structural and morphological development in dependence on the deposition cycle of the constituent binary components by transmission electron microscopy and electron diffraction investigations. The thickness of the alternating deposition layers was varied in the range $0.40<~n<~\mathrm{1.66.}$ From the systematic investigations we could gain new insight into the mechanisms of the reconstruction of group-V stabilized growth surfaces and of the general role surface reconstruction processes play in CuPt superlattice ordering. A competitive interaction was revealed between the mechanisms of ordering and processes that lead to morphological and compositional modulation structures. The lattice mismatch of the constituent binary alloys and the accumulation of the misfit strains is suggested as the main driving force for the modulation. Those self-organization capabilities of strained epitaxial layers are of considerable interest in view of low-dimensional confinement formations.