First-principles calculations of 002 structure factors for electron scattering in strained<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>In</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi>Ga</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:mi>As</mml:mi></mml:mrow></mml:math>

Rosenauer, A.; Schowalter, Marco; Lamoen, D.

doi:10.1103/physrevb.72.085326

Cited by 49 publications

(47 citation statements)

References 30 publications

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“…The intensity of HAADF-STEM images was simulated using the STEMsim program [56] for varying Al-concentration y in dependence of the TEM lamella thickness. The static atomic displacement (SAD, [57][58][59]) in AlGaN can be neglected [55]. From the experimental image, an intensity profile along the growth direction was extracted.…”

Section: Al-concentration In Algan Layersmentioning

confidence: 99%

Microstructural and compositional analyses of GaN‐based nanostructures

Pretorius

Schmidt

Aschenbrenner

et al. 2011

Physica Status Solidi (b)

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Composition and microstructure of GaN-based island structures and distributed Bragg reflectors (DBRs) were investigated with transmission electron microscopy (TEM). We analysed free-standing InGaN islands and islands capped with GaN. Growth of the islands performed by molecular beam epitaxy (MBE) and metal organic vapour phase epitaxy (MOVPE) resulted in different microstructures. The islands grown by MBE were plastically relaxed. Cap layer deposition resulted in a rapid dissolution of the islands already at early stages of cap layer growth. These findings are confirmed by grazingincidence X-ray diffraction (GIXRD). In contrast, the islands grown by MOVPE relax only elastically.Strain state analysis (SSA) revealed that the indium concentration increases towards the tips of the islands. For an application as quantum dots, the islands must be embedded into DBRs. Structure and composition of Al y Ga 1-y N/GaN Bragg reflectors on top of an AlGaN buffer layer and In x Al 1-x N/ GaN Bragg reflectors on top of a GaN buffer layer were investigated. Specifically, structural defects such as threading dislocations (TDs) and inversion domains (IDs) were studied, and we investigated thicknesses, interfaces and interface roughnesses of the layers. As the peak reflectivities of the investigated DBRs do not reach the theoretical predictions, possible reasons are discussed.

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Section: Al-concentration In Algan Layersmentioning

confidence: 99%

Microstructural and compositional analyses of GaN‐based nanostructures

Pretorius

Schmidt

Aschenbrenner

et al. 2011

Physica Status Solidi (b)

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“…As 2 source molecules were used. (002) amplitude is compared with (002) Fourier components calculated by the Bloch-wave method with structure factors which take also static atomic displacements into account [18]. Local thickness values of the TEM sample in regions with known composition, i.e.…”

Section: Methodsmentioning

confidence: 99%

Transmission electron microscopy investigation of segregation and critical floating-layer content of indium for island formation inInxGa1−xAs

et al. 2006

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“…For details, see Refs. [7,8]. In the latter report, we found that SAD from VFF are accurate to a few picometres, being less than mean thermal vibrational amplitudes.…”

Section: Modelling Bonding and Sad Effects On Electron Structure Factorsmentioning

confidence: 64%

TEM 3-beam study of annealing effects in InGaNAs using ab-initio structure factors for strain-relaxed supercells

Müller

Schowalter

Rubel

et al. 2011

J. Phys.: Conf. Ser.

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TEM 3-beam study of annealing effects in InGaNAs using ab-initio structure factors for strainrelaxed supercells Abstract. We report on a Transmission Electron Microscopy 3-beam technique based on the interference of 000, 200 and 220. Nonlinear imaging artefacts are eliminated by Fourier filtering, yielding 200 and 220 lattice fringe images, from which chemically sensitive contrast and strain are measured, respectively. In this way, In and N composition can be mapped at atomic scale in quaternary InGaNAs by comparison with simulated reference data. Our Bloch wave simulations are based on structure factors derived from supercells with 10 6 atoms, which have been strain-relaxed by valence force field methods. Additionally, the influence of electron redistributions due to chemical bonding is accounted for by modified atomic scattering amplitudes derived from density functional theory. By comparing local compositions in an annealed In 0.28 Ga 0.72 N 0.025 As 0.975 sample with its as-grown counterpart, we find homogenisation of InGaNAs layer thickness and -stoichiometry upon annealing.

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First-principles calculations of 002 structure factors for electron scattering in strainedInxGa1−xAs

Cited by 49 publications

References 30 publications

Microstructural and compositional analyses of GaN‐based nanostructures

Microstructural and compositional analyses of GaN‐based nanostructures

Transmission electron microscopy investigation of segregation and critical floating-layer content of indium for island formation inInxGa1−xAs

TEM 3-beam study of annealing effects in InGaNAs using ab-initio structure factors for strain-relaxed supercells

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