Strain induced self organized growth of lateral periodic strained layer superlattices on off-oriented substrates by metalorganic vapour phase epitaxy

Abstract

The strain induced self organization of lateral periodic (GaIn)As Ga(PAs) strained layer superlattice (SLS) structures is investigated as a function of strain and of the surface step configuration introduced by the substrate off-orientation. The structural properties of the samples, deposited by metalorganic vapour phase epitaxy (MOVPE), are determined by high resolution X-ray diffraction (XRD), X-ray reciprocal space mapping and cross-sectional as well as plan-view transmission electron microscopy (TEM). The introduction of surface steps caused by the substrate off-orientation leads to the strain induced generation of laterally ordered macrosteps. The separation of the macrosteps depends on the off-orientation angle, but not significantly on strain. The orientation of the macrosteps is always parallel to the direction of the surface steps. The formation of macrosteps results in the wire-like deposition of (GaIn)As at the macrosteps. The possibility of applying this concept for the direct deposition of quantum wire structures is briefly discussed.