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We present a detailed x-ray diffraction study of the strain in InAs/GaSb superlattices grown by molecular beam epitaxy. The superlattices were grown with either InSb or GaAs interfaces (IFs). We show that the superlattice morphology, either planar or nanostructured, is dependent on the chemical bonds at the heterointerfaces. In both cases, the misfit strain has been determined for the superlattice layers and the IFs. We also determined how the magnitude and sign of this strain is crucial in governing the morphology of the superlattice. Our analysis suggests that the growth of self-assembled nanostructures may be extended to many systems generally thought to have too small a lattice mismatch. [ABSTRACT FROM AUTHOR]

Lateral composition modulation in InAs/AlAs short-period superlattices was investigated by x-ray grazing-incidence diffraction and coplanar x-ray diffraction at a “normal” wavelength and at an anomalous wavelength, for which diffraction from the (200) planes does not exhibit a chemical contrast. The experimental data were compared with theoretical simulations assuming that the interfaces consist of a periodic sequence of monoatomic steps. The displacement field in the superlattice was calculated by continuum elasticity and using a valence-force field method. From the fit of the experimental data to the theory, the lengths of individual atomic terraces were determined. [ABSTRACT FROM AUTHOR]

We report the analysis of lateral composition modulation in (InAs)[sub m]/(GaSb)[sub m] superlattices by x-ray diffraction. Vertical and lateral satellite peaks for a 140 period structure were observed. The lateral modulation wavelength, average superlattice composition, and vertical superlattice wavelength were determined. The lateral modulation was observed only along one in-plane direction resulting in quantum wire-like structures along the [1&1macr;0] direction. The unconventional structure of the lateral composition modulation, in which the stacking of the layers leads to a doubling of the vertical superlattice period, is discussed. [ABSTRACT FROM AUTHOR]

Presents a study which performed theoretical simulations of x-ray double-crystal diffraction rocking curves for strain-relaxed superlattices based on x-ray dynamical diffraction theory. Details on calculations of rocking curves; Description of the model structure used for the calculation; Method used in preparing InGaAs, gallium arsenide, GeSi and silicon superlattices.

Presents a study which investigated the Si[sub1-subx]Ge[subx]/Si strained-layer superlattices grown by molecular beam epitaxy on silicon substrates by x-ray double crystal diffraction and x-ray grazing incidence diffraction. Components of the superlattices; Discussion on lattice relaxation; Results of double-crystal diffraction.

Reports on the simulation of interference effects in the x-ray double-crystal rocking curves of Ge[subx]Si[sub1-x]/silicon strained-layer superlattices (SLS) on the x-ray dynamical scattering theory. Diffraction rocking curve of a nominal SLS sample.

Presents a study which examined Ge[subx]Si[sub1-x]/Si strained-layer super lattices by means of double-crystal x-ray rocking curves. Discussion on the structural characterization of Ge[subx]Si[sub1-x]/Si heterostructures; Result of molecular beam epitaxy of the structures; Calculation of the theoretical simulation of super lattices.

The lateral composition modulation in (InAs)[sub n]/(AlAs)[sub m] short-period superlattices was studied by means of synchrotron x-ray diffraction. By choosing specific diffraction vectors having a large component closely parallel to the modulation direction, we are able to observe a number of lateral satellite peaks around the zero-order short-period superlattice peak. A model, incorporating both composition and strain, is used to simulate the intensities of these satellites. Our results provide a quantitative fit and permit the evaluation of the composition amplitude. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]