Röntgentopographische Untersuchungen an CdTe-Einkristallen

1981 ◽  
Vol 157 (3-4) ◽  
Author(s):  
P. Buck ◽  
M. Nagel
Keyword(s):  
Dislocation Density ◽  
Single Crystals ◽  
Vapor Phase ◽  
Burgers Vector ◽  
X Ray

AbstractThe perfection of single crystals of CdTe grown from the vapor phase has been studied by X-ray topography. Results show that the main defects are dislocations with Burgers vector of the [unk] [110] type. Occasionally those of the [unk] [11[unk]] type are observed. The majority of the dislocations are curved and tangled. The dislocation density is about 10

scholarly journals A Technique for Producing Strain-Free Flat Surfaces on Single Crystals of Ice

1970 ◽  
Vol 9 (57) ◽  
pp. 385-390 ◽  
Author(s):  
T. M Tobin ◽  
K. Itagaki
Keyword(s):  
Dislocation Density ◽  
Single Crystals ◽  
Aluminum Surface ◽  
Ice Crystal ◽  
X Ray ◽  
Flat Surfaces ◽  
Etch Pit

The top surface of an accurately aligned ice crystal is melted by an aluminum surface and then frozen to a warm “Lucite” plate ant! tapped free. Etch-pit development shows that the dislocation density on the resulting surface is similar to die bulk dislocation density determined by X-ray topographic methods.

Distribution of Dislocation Density in Tubes from Zr-Based Alloys by X-Ray Data

2005 ◽  
Vol 105 ◽  
pp. 89-94 ◽  
Author(s):  
Margarita Isaenkova ◽  
Yuriy Perlovich
Keyword(s):  
Dislocation Density ◽  
Domain Size ◽  
Ray Method ◽  
Coherent Domain Size ◽  
Texture Measurement ◽  
Burgers Vector ◽  
X Ray ◽  
Pole Figures ◽  
Coherent Domain

As applied to tubes from Zr-based alloys, the X-ray method was developed to determine the dislocation density distribution in a-Zr depending on the orientation of Burgers vector. The method consists in registration of X-ray line profiles by each successive position of the sample in the course of diffractometric texture measurement using reflections of two orders, the following determination of coherent domain size and lattice distortion by means of the Warren-Averbach method for each orientation of reflecting planes, separate calculation of the density of c- and a-dislocations with all possible orientations of Burgers vector and presentation of results in generalized pole figures. Obtained data testify that the dislocation density varies within very wide intervals of several orders of magnitude depending on the grain orientation both in as-rolled and annealed tubes. Features of the constructed dislocation distributions are closely related to the crystallographic texture of studied tubes.

scholarly journals A Technique for Producing Strain-Free Flat Surfaces on Single Crystals of Ice

1970 ◽  
Vol 9 (57) ◽  
pp. 385-390 ◽  
Author(s):  
T. M Tobin ◽  
K. Itagaki
Keyword(s):  
Dislocation Density ◽  
Single Crystals ◽  
Aluminum Surface ◽  
Ice Crystal ◽  
X Ray ◽  
Flat Surfaces ◽  
Etch Pit

The top surface of an accurately aligned ice crystal is melted by an aluminum surface and then frozen to a warm “Lucite” plate ant! tapped free. Etch-pit development shows that the dislocation density on the resulting surface is similar to die bulk dislocation density determined by X-ray topographic methods.

Inhomogeneous Distribution of Dislocation Density as Manifestation of Multiscale Structure in Tubes from Zr - Based Alloys

2003 ◽  
Vol 779 ◽  
Author(s):  
Yuriy Perlovich ◽  
Margarita Isaenkova
Keyword(s):  
Dislocation Density ◽  
Domain Size ◽  
Nuclear Industry ◽  
Ray Method ◽  
Coherent Domain Size ◽  
Texture Measurement ◽  
Burgers Vector ◽  
X Ray ◽  
Pole Figures ◽  
Coherent Domain

AbstractAn X-ray method was developed to determine the dislocation density in metal materials as a distribution depending on the orientation of Burgers vector. The method includes registration of X-ray line profiles by each successive position of the sample in the course of diffractometric texture measurement using reflections of two orders, the following determination of coherent domain size and lattice distortion by means of the Warren-Averbach method for each orientation of reflecting planes, separate calculation of the density of c- and a-dislocations with all possible orientations of Burgers vector and presentation of results in the generalized pole figures. The method was used to determine the dislocation density in tubes of Zr-based alloys for nuclear industry. Obtained data show, that the dislocation density varies within very wide interval of several orders of magnitude depending on the grain orientation both in as-rolled and annealed tubes. Features of the dislocation distribution in tubes are closely related to their crystallographic texture.

X-Ray Topography Of A Single Superscrew Dislocation In 6H-SiC Through All {100} Faces

1996 ◽  
Vol 442 ◽  
Author(s):  
W. M. Vetter ◽  
M. Dudley
Keyword(s):  
Single Crystals ◽  
Semiconductor Devices ◽  
Image Contrast ◽  
Hexagonal Prism ◽  
Burgers Vector ◽  
X Ray ◽  
Stress Components ◽  
Sic Wafer

AbstractMicropipes, the hollow cores of superscrew dislocations that lie along the c-direction in SiC single crystals, are quite deleterious to the performance of semiconductor devices. In the x-ray topography of longitudinal-cut samples of these crystals, topographs in the reflection (006) show dislocation image contrast associated with the superscrew dislocations lying along the c-axis of the crystal, which is also the direction of the dislocations' Burgers vectors. In the (110) reflection, whose g-vector is perpendicular to the c-axis and the dislocations' Burgers vector, there is also an image of the superscrew dislocation formed, albeit weaker than the corresponding image in the (006) reflection. This dislocation image is thought to represent stress components of the superscrew dislocation in directions perpendicular to the c-axis.In order to investigate the origin of these stress components, steps have been carried out to determine whether the dislocation image is anisotropic in all possible reflections where g={110}. To achieve this we have excised a hexagonal prism-shaped sample from a 6H-SiC wafer, 100μm wide, polished along the six {100} crystallographic faces, such that a single micropipe ran along the axis of the sample. This enabled x-ray topographs to be taken through each of these {100} faces

Dislocation Arrangement in a Thick LEO GaN Film on Sapphire

1999 ◽  
Vol 595 ◽  
Author(s):  
Kathleen A. Dunn ◽  
Susan E. Babcock ◽  
Donald S. Stone ◽  
Richard J. Matyi ◽  
Ling Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Dislocation Density ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Burgers Vector ◽  
X Ray ◽  
The Third ◽  
Dislocation Arrangement ◽  
Gan Film

AbstractDiffraction-contrast TEM, focused probe electron diffraction, and high-resolution X-ray diffraction were used to characterize the dislocation arrangements in a 16[.proportional]m thick coalesced GaN film grown by MOVPE LEO. As is commonly observed, the threading dislocations that are duplicated from the template above the window bend toward (0001). At the coalescence plane they bend back to lie along [0001] and thread to the surface. In addition, three other sets of dislocations were observed. The first set consists of a wall of parallel dislocations lying in the coalescence plane and nearly parallel to the substrate, with Burgers vector (b) in the (0001) plane. The second set is comprised of rectangular loops with b = 1/3 [11 20] (perpendicular to the coalescence boundary) which originate in the coalescence boundary and extend laterally into the film on the (1 100). The third set of dislocations threads laterally through the film along the [1 100] bar axis with 1/3<11 20>-type Burgers vectors These sets result in a dislocation density of ∼109 cm−2. High resolution X-ray reciprocal space maps indicate wing tilt of ∼0.5°.

High Resolution X-ray Diffraction Analysis of GaN-Based Heterostructures Grown by OMVPE

1996 ◽  
Vol 449 ◽  
Author(s):  
M.S. Goorsky ◽  
A.Y. Polyakov ◽  
M. Skowronski ◽  
M. Shin ◽  
D.W. Greve
Keyword(s):  
High Resolution ◽  
Dislocation Density ◽  
Layer Thickness ◽  
Vapor Phase ◽  
Edge Dislocation ◽  
Initial Level ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Perfection ◽  
Misorientation Angles

ABSTRACTWe demonstrate the use of triple axis diffraction measurements, including Φ scans (in which the sample is rotated about an axis perpendicular to its surface) to assess the crystal perfection of wurtzite GaN layers on sapphire grown using different pre-nitridation growth treatments by or-ganometallic vapor phase epitaxy. The Φ scans determine the in-plane misorientation angles between the crystallites and hence provide information on the edge dislocation density. Using glancing incidence (1014) and (1015) reflections, we determined that the misorientation among the GaN crystallites decreases with increasing layer thickness and that the pre-nitridation conditions control the initial level of misorientation. Triple axis ω and ω-2θ scans around the (0002) reflection did not show a systematic trend with increasing layer thickness. However, layers grown without a pre-nitridation step tended to exhibit higher values of both mosaic spread and strain. The appropriate asymmetric reflections for GaN-based Φ scan measurements are determined using structure factor calculations, which are presented here.

scholarly journals Dislocation density and Burgers vector population in fiber-textured Ni thin films determined by high-resolution X-ray line profile analysis

2012 ◽  
Vol 45 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Gábor Csiszár ◽  
Karen Pantleon ◽  
Hossein Alimadadi ◽  
Gábor Ribárik ◽  
Tamás Ungár
Keyword(s):  
Thin Films ◽  
High Resolution ◽  
Dislocation Density ◽  
Line Profile ◽  
Profile Analysis ◽  
Domain Size ◽  
Line Profile Analysis ◽  
Burgers Vector ◽  
X Ray ◽  
Vector Population

Nanocrystalline Ni thin films have been produced by direct current electrodeposition with different additives and current density in order to obtain 〈100〉, 〈111〉 and 〈211〉 major fiber textures. The dislocation density, the Burgers vector population and the coherently scattering domain size distribution are determined by high-resolution X-ray diffraction line profile analysis. The substructure parameters are correlated with the strength of the films by using the combined Taylor and Hall–Petch relations. The convolutional multiple whole profile method is used to obtain the substructure parameters in the different coexisting texture components. A strong variation of the dislocation density is observed as a function of the deposition conditions.

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