Characterization of edge dislocation density through X-ray diffraction rocking curves

The dislocation density of GaN thick films has been measured by high-resolution X-ray diffraction. The results show that both the edge dislocations and the screw dislocation reduce with increasing the GaN thickness. And the edge dislocations have a larger fraction of the total dislocation densities, and the densities for the edge dislocation with increasing thickness reduce less in contrast with those for the screw dislocation.

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

MRS Proceedings ◽

10.1557/proc-449-489 ◽

1996 ◽

Vol 449 ◽

Cited By ~ 2

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.

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Compositional and Structural Characterization of Heterostructure InGaN-Based Light-Emitting Diode by High Resolution X-Ray Diffraction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.620.22 ◽

2012 ◽

Vol 620 ◽

pp. 22-27 ◽

Cited By ~ 1

Author(s):

Ahmad Hadi Ali ◽

Ahmad Shuhaimi ◽

Hassan Zainuriah ◽

Yushamdan Yusof

Keyword(s):

High Resolution ◽

Dislocation Density ◽

Structural Characterization ◽

Light Emitting Diode ◽

X Ray Diffraction ◽

Rocking Curve ◽

Light Emitting ◽

X Ray ◽

Multi Quantum Well

This paper focuses on the compositional and structural characterization of InGaN-based light-emitting diode (LED) using high resolution x-ray diffraction (HRXRD) system. The LED was epitaxially grown on Si (111) substrate that comprises of In0.11Ga0.89N multi-quantum-well (MQW) active layer. Phase analysis 2θ-scan proved the composition of GaN (0002) and (0004) at 34.63oand 72.98o, respectively. Rocking curveφ-scan showed six significant peaks of the hexagonal GaN structures with consistent angular gaps of ~60o. From x-ray rocking curve (XRC)ω-scan, screw and mix dislocation density is found as 2.85 × 109cm-2, while pure edge dislocation density is found as 2.23 × 1011cm-2.

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Structural Properties of Al-Cu Thin Films after Heat Treatment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.609.87 ◽

2009 ◽

Vol 609 ◽

pp. 87-93

Author(s):

S. Lallouche ◽

M.Y. Debili

Keyword(s):

Heat Treatment ◽

Grain Size ◽

Dislocation Density ◽

Annealing Temperature ◽

Exothermic Peak ◽

Thermal Study ◽

X Ray Diffraction ◽

X Ray ◽

Decomposition Behaviour

In this work we are interested by the decomposition behaviour after heat treatment at 500°C of nanostructured Al-Cu deposits, prepared by radio frequency (13.56MHz) magnetron sputtered from composite targets. The use of X-ray diffraction leads to the characterization of different structures and the estimation of grain size and dislocation density. The grain size of the films is found to increase with annealing. The dislocation density is observed to exhibit a decrease trend with annealing temperature which leads to a reduction in the concentration of lattice imperfections A specific thermal study of the Al-Cu deposits, by combined thermal analysis (TDA/TG) permit to follow the structural behavior of the deposits with heat treatment. For Al-7.21at%Cu deposit, the exothermic peak convolution may be due to the elimination of micro deformations present in the sample.

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DISLOCATION DENSITY IN SrTiO3 FILM GROWN ON DyScO3 BY PULSE LASER ABLATION

Surface Review and Letters ◽

10.1142/s0218625x07010251 ◽

2007 ◽

Vol 14 (04) ◽

pp. 779-782

Author(s):

Z. Y. ZHAI ◽

X. Z. LI ◽

S. S. ZHI ◽

X. S. WU ◽

J. H. HAO ◽

...

Keyword(s):

Dislocation Density ◽

Pulse Laser ◽

Edge Dislocation ◽

Lattice Parameter ◽

Abnormal Behavior ◽

X Ray Diffraction ◽

X Ray ◽

Dislocation Densities ◽

Srtio3 Film

SrTiO 3 films are fabricated on DyScO 3 substrates by pulse laser deposition. In situ X-ray diffraction (XRD) is used to characterize the thermal expansion coefficient at low temperature. The abnormal behavior in lattice parameter at 80 K may be the hint of a phase transition. High resolution XRD is performed to detect the two kinds of dislocations, i.e. screw and edge. Results show that the density of edge dislocation is a little larger than that of the screw one. The total dislocation density has the order of about 108 cm-2. Edge dislocation density decreases with the increase of the film thickness. We argue that the ratio between these two dislocation densities results in the growth mode of the film.

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The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071107 ◽

1973 ◽

Vol 31 ◽

pp. 132-133 ◽

Cited By ~ 1

Author(s):

R. E. Herfert

Keyword(s):

Surface Characterization ◽

Analytical Techniques ◽

X Ray Diffraction ◽

Depth Of Penetration ◽

X Ray ◽

The Past ◽

Transmission Electron ◽

Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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High Resolution Replication of Organoclay Surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055126 ◽

1982 ◽

Vol 40 ◽

pp. 576-577

Author(s):

W. W. Barker ◽

W. E. Rigsby ◽

V. J. Hurst ◽

W. J. Humphreys

Keyword(s):

Clay Mineral ◽

Organic Molecule ◽

Organic Molecules ◽

X Ray Diffraction ◽

Xrd Pattern ◽

X Ray ◽

Naturally Occurring ◽

Silicate Layers ◽

Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

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Synthesis and characterization of TiN / Ti / AISI 410 coatings

Journal of Sciences and Engineering ◽

10.32829/sej.v2i1.54 ◽

2018 ◽

Vol 2 (1) ◽

pp. 7

Author(s):

S Chirino ◽

Jaime Diaz ◽

N Monteblanco ◽

E Valderrama

Keyword(s):

Synthesis And Characterization ◽

Photoemission Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Columnar Grains ◽

Tin Thin Films ◽

Steel Aisi ◽

Interacting Surfaces ◽

Stainless Steel Aisi

The synthesis and characterization of Ti and TiN thin films of different thicknesses was carried out on a martensitic stainless steel AISI 410 substrate used for tool manufacturing. The mechanical parameters between the interacting surfaces such as thickness, adhesion and hardness were measured. By means of the scanning electron microscope (SEM) the superficial morphology of the Ti/TiN interface was observed, finding that the growth was of columnar grains and by means of EDAX the existence of titanium was verified. Using X-ray diffraction (XRD) it was possible to observe the presence of residual stresses (~ -3.1 GPa) due to the different crystalline phases in the coating. Under X-ray photoemission spectroscopy (XPS) it was possible to observe the molecular chemical composition of the coating surface, being Ti-N, Ti-N-O and Ti-O the predominant ones.

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Studies on the Preparation, Characterization and Solubility of -Cyclodextrin-Roxythromycin Inclusion Complexes

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2009.2.2.5 ◽

2009 ◽

Vol 2 (2) ◽

pp. 523-530

Author(s):

D. Nagasamy Venkatesh ◽

S. Karthick ◽

M. Umesh ◽

G. Vivek ◽

R.M. Valliappan ◽

...

Keyword(s):

Dissolution Rate ◽

Inclusion Complexes ◽

Phase Solubility ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Ir Studies ◽

Poorly Soluble ◽

Poorly Soluble Drug

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.

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New Coordination Compounds of Fe(III) with Organic Ligands

Revista de Chimie ◽

10.37358/rc.08.12.2055 ◽

2009 ◽

Vol 59 (12) ◽

Author(s):

Mihaela Flondor ◽

Ioan Rosca ◽

Doina Sibiescu ◽

Mihaela-Aurelia Vizitiu ◽

Daniel-Mircea Sutiman ◽

...

Keyword(s):

Chemical Analysis ◽

Complex Compounds ◽

Organic Ligands ◽

X Ray Diffraction ◽

X Ray ◽

Elemental Chemical Analysis ◽

Structural Formulae ◽

Paramagnetic Properties

In this paper the synthesis and the study of some complex compounds of Fe(III) with ligands derived from: 2-(4-chloro-phenylsulfanyl)-1-(2-hydroxy-3,5-diiodo-phenyl)-ethanone (HL1), 1-(3,5-dibromo-2-hydroxy-phenyl)-2-phenylsulfanyl-ethanone(HL2), and 2-(4-chloro-phenylsulfanyl)-1-(3,5-dibromo-2-hydroxy-phenyl)-ethanone (HL3) is presented. The characterization of these complexes is based on method as: the elemental chemical analysis, IR and ESR spectroscopy, M�ssbauer, the thermogravimetric analysis and X-ray diffraction. Study of the IR and chemical analysis has evidenced that the precipitates form are a complexes and the combination ratio of M:L is 1:2. The central atoms of Fe(III) presented paramagnetic properties and a octaedric hybridization. Starting from this precipitation reactions, a method for the gravimetric determination of Fe(III) with this organic ligands has been possible. Based on the experimental data on literature indications, the structural formulae of the complex compounds are assigned.

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