Strain and structural characterization of Zn1−xCdxSe laser structures grown on GaAs and InGaAs (001) substrates

Abstract

X-ray reciprocal space mapping has been used to investigate the strain status of microgun-pumped blue and blue-green laser structures. The devices exploit graded-index, separate confinement Zn1−xCdxSe/ZnSe heterostructures grown on InGaAs or GaAs substrates by molecular-beam epitaxy. The location of the reciprocal lattice point of the ZnSe buffer layer 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 III–V substrate relative to ZnSe. We associate such a phenomenon with the presence of the highly strained laser structure coupled with preferential strain relaxation at the II–VI/III–V heterointerface.

Structural analysis of CdO layers grown on r-plane sapphire (011¯2) by

“…direction. Before any quantitative determination of the lattice parameters is made, the relative tilt between layer and substrate must be taken into account and the positions of the layer reciprocal lattice points must be corrected [19,20]. The lattice parameter in the growth direction was determined from (0 0 2) and (0 0 4) symmetrical reflections in four different azimuthal positions, achieved by 901 rotations of the sample around its normal [21], and from reciprocal space maps on {2 2 4} asymmetrical reflections.…”

Combined transmission electron microscopy and cathodoluminescence studies of degradation in electron-beam-pumped Zn1−xCdxSe/ZnSe blue-green lasers

“…296͒ yielded in-plane elastic strains of Ϫ1.02%, Ϫ1.24%, and Ϫ1.60%, respectively. 23 Dislocation growth and climb occurs through the diffusion of point defects. Since the diffusivity of point defects at room temperature is very low, dislocation motion is usually negligible.…”