scholarly journals A Study of Defects in InAs/GaSb Type-II Superlattices Using High-Resolution Reciprocal Space Mapping

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4940
Author(s):  
Iwona Sankowska ◽  
Agata Jasik ◽  
Krzysztof Czuba ◽  
Jacek Ratajczak ◽  
Paweł Kozłowski ◽  
...  
Keyword(s):  
High Resolution ◽  
Diffuse Scattering ◽  
Defect Density ◽  
Stacking Faults ◽  
Diffraction Method ◽  
Reciprocal Space ◽  
Type Ii ◽  
Scattering Intensity ◽  
Type Ii Superlattices ◽  
Diffuse Scattering Intensity

In this paper, he study of defects in InAs/GaSb type-II superlattices using high-resolution an x-ray diffraction method as well as scanning (SEM) and transmission (TEM) electron microscopy is presented. The investigated superlattices had 200 (#SL200), 300 (#SL300), and 400 (#SL400) periods and were grown using molecular beam epitaxy. The growth conditions differed only in growth temperature, which was 370 °C for #SL400 and #SL200, and 390 °C for #SL300. A wings-like diffuse scattering was observed in reciprocal space maps of symmetrical (004) GaSb reflection. The micrometer-sized defect conglomerates comprised of stacking faults, and linear dislocations were revealed by the analysis of diffuse scattering intensity in combination with SEM and TEM imaging. The following defect-related parameters were obtained: (1) integrated diffuse scattering intensity of 0.1480 for #SL400, 0.1208 for #SL300, and 0.0882 for #SL200; (2) defect size: (2.5–3) μm × (2.5–3) μm –#SL400 and #SL200, (3.2–3.4) μm × (3.7–3.9) μm –#SL300; (3) defect diameter: ~1.84 μm –#SL400, ~2.45 μm –#SL300 and ~2.01 μm –#SL200; (4) defect density: 1.42 × 106 cm−2 –#SL400, 1.01 × 106 cm−2 –#SL300, 0.51 × 106 cm−2 –#SL200; (5) diameter of stacking faults: 0.14 μm and 0.13 μm for #SL400 and #SL200, 0.30 μm for #SL300.

Study of Diffuse Scattering by Means of High Resolution Structure Images

1976 ◽  
Vol 34 ◽  
pp. 476-477
Author(s):  
Sumio Iijima ◽  
G. R. Anstis
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Diffuse Scattering ◽  
Reciprocal Space ◽  
The Other ◽  
X Ray ◽  
Actual Model ◽  
High Resolution Structure ◽  
Made In ◽  
Resolution Structure

Disorders in crystals with relatively simple structures which gave diffuse scattering have been extensively studied by X-ray or neutron diffraction methods. All these investigations were based on traditional diffraction methods and observations were made in reciprocal space (note observable diffraction intensities can be considered only in terms of interatomic vectors) and therefore the results obtained there leaves considerable ambiguity, particularly when we try to derive an actual model of the disordered crystals. A solution of this problem will be given only by knowing all atom positions in an assembly of atoms and for this case the observable diffracted intensity is given bywhere (xi,yi) and (xj,yj) represent position vectors of the i th and j th atoms with scattering factors fi and fj from an arbitrary origin. On the other hand, a crystal containing imperfections can be defined by

A Comparison of Diffuse Scattering by Defects Measured in Anomalous Transmission and Near Bragg Reflections

1973 ◽  
Vol 28 (5) ◽  
pp. 626-632 ◽  
Author(s):  
Bennett C. Larson ◽  
F. W. Young
Keyword(s):  
Size Distribution ◽  
Diffuse Scattering ◽  
Bragg Reflection ◽  
Scattering Intensity ◽  
Wide Range ◽  
Anomalous Transmission ◽  
Diffuse Scattering Intensity ◽  
Average Size ◽  
Exponential Size ◽  
Good Agreement

The diffuse scattering from neutron-irradiation-produced defects in copper was measured in anomalous transmission and near the 111 Bragg reflection. The results were related through the theory of Dederichs, and the intensities and forms of the scattering curves obtained from the two measurements were found to be in good agreement over a wide range of defect concentrations and sizes. It was shown that the intercept of a plot of the diffuse scattering intensity Is (q0) vs In (q0) is at q0=e1/2/R for defects of uniform radius R and at q0 ≌1/R0 e for an exponential size distribution of average size R0 .

Simulation Study of Strain-Related Morphology in YBa2Cu3−x(Al,Fe)xO7

1992 ◽  
Vol 291 ◽  
Author(s):  
Zhi-Xiong Cai ◽  
Yimei Zhu ◽  
David O. Welch
Keyword(s):  
Monte Carlo ◽  
Oxygen Concentration ◽  
Diffuse Scattering ◽  
Lattice Gas ◽  
Lattice Gas Model ◽  
Scattering Data ◽  
Concentration Wave ◽  
Scattering Intensity ◽  
Impurity Atoms ◽  
Diffuse Scattering Intensity

ABSTRACTA new simulation method which combines the merits of Monte Carlo simulation of a lattice gas model and the continuum elasticity theory is described. This method treats the elastic strain energy due to concentration fluctuation of interstitial as a perturbation of a lattice gas model Hamiltonian. We illustrate this method by calculating the diffuse scattering intensity of YBa2Cu3O7 systems doped with trivalent impurity atoms M such as Fe or Al. The oxygen concentration wave amplitudes cq were obtained from Monte Carlo simulations of an anisotropic lattice gas model which represents well the interaction between oxygen atoms in this system. These results are in turn used to calculate the diffuse X-ray scattering intensity caused by the displacement field using concentration wave/displacement wave approach. The results suggest that the small orthorhombic domains associated with the oxygen “cross-link” around impurity atoms M causes the diffuse scattering intensity to fall off with oxygen concentration wave vector q as 1/q2for small qand as 1/q4 for larger q.We also show that the size of such domain can be obtained from diffuse scattering data.

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