STRAIN AND STRUCTURAL CHARACTERIZATION OF ZN1-XCDXSE LASER STRUCTURESGROWN ON GAAS AND INGAAS(001) SUBSTRATES

X-ray reciprocal space mapping has been used to investigate the strain status of microgun-pumped blue and blue-green laser structures. The d evices exploit graded-index, separate confinement Zn1-xCdxSe/ZnSe hete rostructures grown on InGaAs or GaAs substrates by molecular-beam epit axy. The location of the reciprocal lattice point of the ZnSe buffer l ayer within a normally forbidden region of reciprocal space indicates that the ZnSe buffer layer is unusually strained, with an appreciable biaxial tensile strain despite the smaller lattice parameter of the II I-V substrate relative to ZnSe. We associate such a phenomenon with th e presence of the highly strained laser structure coupled with prefere ntial strain relaxation at the II-VI/III-V heterointerface. (C) 1996 A merican Institute of Physics.