Friedel's Law in Electron Diffraction as Applied to the Study of Domain Structures in Non‐Centrosymmetrical Crystals

Serneels, R.; Snykers, M.; Delavignette, P.; Gevers, R.; Amelinckx, S.

doi:10.1002/pssb.2220580127

Cited by 136 publications

(37 citation statements)

References 11 publications

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“…In order to reveal the inversion character of these domains, we have carried out multi-beam dark field experiments with reflections exhibiting the non centrosymmetric character of the crystal. Serneels et al [73] have demonstrated that phys. stat.…”

Section: Identification Of the Inversion Domainsmentioning

confidence: 99%

Atomic Structure of Extended Defects in Wurtzite GaN Epitaxial Layers

Ruterana

Nouet

2001

phys. stat. sol. (b)

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Using high resolution electron microscopy, atomistic modelling and image simulations, typical contrast was identified for most of the extended defects which form in epitaxial GaN layers. There are three types of defects which propagate into the active layers: the threading dislocations, prismatic stacking faults and inversion domains. The atomic structure of the a pure edge threading dislocations was shown to exhibit 5/7, or 8 atom cycles. The two configurations were observed at a similar frequency for isolated dislocations and low angle grain boundaries. Coincidence grain boundaries were studied and they were made of pure edge a dislocations with the above identified atomic structures. A topological analysis of high angle grain boundaries was carried out in order to determine the defect content at the interfaces. The reconstruction of some boundaries was only possible by taking into account the occurrence of structural units which exhibit 4 atom ring cycles for the dislocation cores. The f1 2 210g stacking fault has two atomic configurations in wurtzite (Ga, Al, In)N with 1/2 h10 1 11i and 1/6 h20 2 23i displacement vectors. It originates from steps at the SiC surface and it can form on a flat (0001) sapphire surface. The two atomic configurations have comparable energy in AlN, whereas the 1/2 h10 1 11if1 2 210g atomic configuration should be more stable in GaN and InN. Observations carried out in plan-view show the 1/2 h10 1 11if1 2 210g atomic configuration in GaN layers. The 1/6 h20 2 23i configuration was found inside the AlN buffer layer in cross section observations. It folds rapidly to the basal plane, and when back into the prismatic plane, it bears the 1/2 h10 1 11if1 2 210g atomic configuration. The f10 1 10g inversion domains in GaN layers grown on sapphire substrate were identified in multi-beam dark field images and by convergent beam electron diffraction. In the investigated samples, Holt and V models are shown to form in samples depending on the growth conditions. The samples containing Holt inversion domains exhibited a flat surface morphology, whereas the V IDBs were observed in the centre of small pyramids (100 nm high) protruding at the sample surface. The Holt inversion domains were always smaller (< 20 nm), at quite high densities (2.5 Â 10 10 cm --2 ), whereas the V ones could reach 50 nm and one order of magnitude lower density. The inversion domains were found to be generated mostly at sapphire surface steps where they minimized the large misfit along the c axis (20%).

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Section: Identification Of the Inversion Domainsmentioning

confidence: 99%

Atomic Structure of Extended Defects in Wurtzite GaN Epitaxial Layers

Ruterana

Nouet

2001

phys. stat. sol. (b)

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“…One of them, proposed by Serneels et al [7], is based on the violation of Friedel's law in the case when multiple diffraction conditions along a noncentrosymmetric zone axis are applied. GaN.…”

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confidence: 99%

Inversion domains in AlN grown on (0001) sapphire

Jasiński

Liliental‐Weber

Paduano

et al. 2003

Applied Physics Letters

114

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Al-polarity inversion domains formed during AlN layer growth on (0001) sapphire were identified using transmission electron microscopy (TEM). They resemble columnar inversion domains reported for GaN films grown on (0001) sapphire. However, for AlN, these columns have a V-like shape with boundaries that deviate by 2 ± 0.5 o from the c-axis.TEM identification of these defects agrees with the post-growth surface morphology as well as with the microstructure revealed by etching in hot aqueous KOH.

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“…In order to prove that V-defects in InN are IDs we used the criterion proposed by Serneels et al [24]. Under multiple diffraction conditions we collected pairs of dark field micrographs of the same V-like defect.…”

mentioning

confidence: 99%

V-shaped inversion domains in InN grown on c-plane sapphire

Jasiński

Liliental‐Weber

et al. 2004

Applied Physics Letters

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Inversion domains with a V-shape were found to nucleate inside a Mg-doped InN heteroepitaxial layer. They resemble Al-polarity domains, observed recently, in Npolarity AlN films. However, the angle between the side-walls of the V-shaped domain and the c-axis differs in these two cases. In InN, this angle is almost two times bigger than that reported for AlN. The origin of V-shaped inversion domains in InN film is not yet clear. a

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Friedel's Law in Electron Diffraction as Applied to the Study of Domain Structures in Non‐Centrosymmetrical Crystals

Cited by 136 publications

References 11 publications

Atomic Structure of Extended Defects in Wurtzite GaN Epitaxial Layers

Atomic Structure of Extended Defects in Wurtzite GaN Epitaxial Layers

Inversion domains in AlN grown on (0001) sapphire

V-shaped inversion domains in InN grown on c-plane sapphire

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