Bragg Diffraction Imaging of CdZnTe Single Crystals

Yildirim, Can; Gout, E.; Pagot, Antoine; Caliste, Thu Nhi Tran; Baruchel, J.; Brellier, D.; Ballet, P.

doi:10.1007/s11664-020-08219-2

Cited by 4 publications

(4 citation statements)

References 12 publications

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“…Under Borrmann contrast imaging conditions, TDs become visible as many-lobed rosette-shaped contrasts in low defect crystals. Similar images have already been observed for TDs in highly absorbing semiconductors such as Ge [ 31 ], GaAs [ 32 , 33 ], CdTe [ 34 ], and ZnGeP 2 [ 35 , 36 , 37 ]. Recently, many-lobed rosette-shaped contrasts of TDs were reported for low-defect Am-GaN for the first time [ 8 ].…”

Section: Resultssupporting

confidence: 78%

Large-Scale Defect Clusters with Hexagonal Honeycomb-like Arrangement in Ammonothermal GaN Crystals

et al. 2022

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In this paper, we investigate, using X-ray Bragg diffraction imaging and defect selective etching, a new type of extended defect that occurs in ammonothermally grown gallium nitride (GaN) single crystals. This hexagonal “honeycomb” shaped defect is composed of bundles of parallel threading edge dislocations located in the corners of the hexagon. The observed size of the honeycomb ranges from 0.05 mm to 2 mm and is clearly correlated with the number of dislocations located in each of the hexagon’s corners: typically ~5 to 200, respectively. These dislocations are either grouped in areas that exhibit “diameters” of 100–250 µm, or they show up as straight long chain alignments of the same size that behave like limited subgrain boundaries. The lattice distortions associated with these hexagonally arranged dislocation bundles are extensively measured on one of these honeycombs using rocking curve imaging, and the ensemble of the results is discussed with the aim of providing clues about the origin of these “honeycombs”.

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Section: Resultssupporting

confidence: 78%

Large-Scale Defect Clusters with Hexagonal Honeycomb-like Arrangement in Ammonothermal GaN Crystals

et al. 2022

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“…So far, XRT using the Borrmann effect has been reported mainly for highly absorbing crystals of semiconductors such as Ge [ 24 ], GaAs [ 25 , 26 ], CdTe [ 27 ] and ZnGeP 2 [ 28 , 29 , 30 ], as well as the electro-optical material KH 2 PO 4 [ 17 ]. In this paper we apply this method for three 1.8 inch highly conductive Am-GaN substrates.…”

Section: Introductionmentioning

confidence: 99%

Structural Analysis of Low Defect Ammonothermally Grown GaN Wafers by Borrmann Effect X-ray Topography

et al. 2021

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X-ray topography defect analysis of entire 1.8-inch GaN substrates, using the Borrmann effect, is presented in this paper. The GaN wafers were grown by the ammonothermal method. Borrmann effect topography of anomalous transmission could be applied due to the low defect density of the substrates. It was possible to trace the process and growth history of the GaN crystals in detail from their defect pattern imaged. Microscopic defects such as threading dislocations, but also macroscopic defects, for example dislocation clusters due to preparation insufficiency, traces of facet formation, growth bands, dislocation walls and dislocation bundles, were detected. Influences of seed crystal preparation and process parameters of crystal growth on the formation of the defects are discussed.

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“…This implies a low divergence beam. This technique was initially implemented in the reflection geometry [10] and was used for the characterisation of crystals and deposited layers with thicknesses in the µm range [12]. In order not to be limited to the near-surface distortion, we use RCI in transmission geometry.…”

Section: Methodsmentioning

confidence: 99%

“…We took advantage of the capabilities of Rocking Curve Imaging (RCI) [10] to perform this investigation. RCI is a Bragg diffraction imaging technique that has been developed and pushed to the limits at the European Synchrotron Radiation Facility (ESRF) over the last twenty years (see, as examples, [11][12][13]). Nowadays, it is able to provide maps of a crystal with an angular resolution in the µradian range.…”

Section: Introductionmentioning

confidence: 99%

Rocking Curve Imaging Investigation of the Long-Range Distortion Field between Parallel Dislocations with Opposite Burgers Vectors

et al. 2021

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We observe a long-range distortion field between parallel dislocations with opposite Burgers vectors in a platelet-shaped single crystal of 4H-SiC with a low dislocation density (~103 cm/cm3). This distortion field is in the µradian range when the distance D between dislocations is in the ~50–250 µm range. We were able to characterise this weak distortion field through Rocking Curve Imaging (RCI), a highly sensitive Bragg diffraction imaging technique using monochromatic synchrotron radiation. From the experimental images, we generate maps of the angle of maximum reflectance (“peak position”) that provide a measurement of the local lattice orientation. Deviations from the crystal matrix orientation are associated with the long-range distortion field around dislocations. Between parallel dislocations with opposite Burgers vectors, this distortion does not decay to zero but towards a constant value α. We propose a simple model considering the angular parameter α characterising the distortion. This model indicates that α should roughly vary as 1/D. This appears to be in fair agreement with our experimental data.

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Bragg Diffraction Imaging of CdZnTe Single Crystals

Cited by 4 publications

References 12 publications

Large-Scale Defect Clusters with Hexagonal Honeycomb-like Arrangement in Ammonothermal GaN Crystals

Large-Scale Defect Clusters with Hexagonal Honeycomb-like Arrangement in Ammonothermal GaN Crystals

Structural Analysis of Low Defect Ammonothermally Grown GaN Wafers by Borrmann Effect X-ray Topography

Rocking Curve Imaging Investigation of the Long-Range Distortion Field between Parallel Dislocations with Opposite Burgers Vectors

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