Layers of ZnSe were grown, by means of molecular beam epitaxy, onto GaAs(001) substrates and were investigated by using grazing-incidence X-ray diffraction, reciprocal space mapping and transmission electron microscopy. The results showed that the Zn/Se beam pressure-ratio which was used during the early stages of ZnSe growth (2nm) strongly affected the structural properties of the overgrown stoichiometric epilayer. The differing strain status of the interface (tensile and compressive for the Zn-rich and Se-rich interfaces, respectively) was directly involved in defect evolution. Whereas roughly the same numbers of 60º dislocations were found in all of the specimens, 3 orders of magnitude more stacking-faults were found in samples with a Zn-rich interface as compared with those with a Se-rich interface. A contraction of the lattice parameter towards the sample-surface, along the growth direction, was observed only in samples which were grown with an excess of Se at the interface. The lattice gradient could be explained by the presence of point defects within the II-VI epilayer thickness. The formation of point defects was favoured by the presence of a Se-rich compressive strained interface.

Influence of the Interface Layer on the Strain Relaxation of ZnSe Epitaxial Layers grown by MBE on (001)GaAs C.Giannini, E.Carlino, P.Sciacovelli, L.Tapfer, M.Sauvage-Simkin, Y.Garreau, N.Jedrecy, M.B.Véron, R.Pinchaux: Journal of Physics D, 1999, 32[10A], A51-5