scholarly journals Hybrid multiple diffraction in semipolar wurtzite materials: (\bf 01\overline{1}2)-oriented ZnMgO/ZnO heterostructures as an illustration

2017 ◽  
Vol 50 (4) ◽  
pp. 1165-1173 ◽  
Author(s):  
Esther de Prado ◽  
M. Carmen Martínez-Tomás ◽  
Christiane Deparis ◽  
Vicente Muñoz-Sanjosé ◽  
Jesús Zúñiga-Pérez
Keyword(s):  
A Priori ◽  
Structural Quality ◽  
Material System ◽  
X Ray Diffraction ◽  
Single Measurement ◽  
Multiple Diffraction ◽  
Out Of Plane ◽  
Low Symmetry ◽  
Symmetric Reflection

X-ray diffraction has been widely used to characterize the structural properties (strain and structural quality) of semiconductor heterostructures. This work employs hybrid multiple diffraction to analyzer-oriented Zn1−xMgxO layers grown by molecular beam epitaxy on ZnO substrates. In such a low-symmetry material system, additional features appear in symmetric reflection scans, which are described as arising from hybrid multiple diffraction. First, the Bragg conditions necessary for these high-order processes to occur are introduced and applied to explain all the observed satellite reflections, identify the planes that contribute and computea priorithe angles at which they are observed. Furthermore, thanks to this hybrid multiple-diffraction technique, it is possible to determine the layer lattice parameters (in-plane and out-of-plane) in an easy and accurate way by using one single measurement in standard symmetric conditions. The achieved precision is at least as high as that obtained from the combination of symmetric and asymmetric reciprocal space map measurements.

An X-ray diffraction study of AgNbO3 and comparison with NaNbO3

1999 ◽  
Vol 14 (4) ◽  
pp. 253-257 ◽  
Author(s):  
C. N. W. Darlington
Keyword(s):  
Diffraction Pattern ◽  
Figure Of Merit ◽  
Parent Phase ◽  
Incident Beam ◽  
Large Error ◽  
High Symmetry ◽  
X Ray Diffraction ◽  
Beam Focusing ◽  
Low Symmetry

The powder diffraction pattern of the perovskite AgNbO3 has been measured using CuKα1 radiation with an incident beam focusing monochromator to eliminate the Kα2 component. Indexing the pattern shows that the multipartite cell is 2×2×4 times that of the pseudocubic subcell. Comparison is made with the diffraction pattern of NaNbO3, which has a similar multipartite unit cell. There are strong similarities, but close inspection shows that the structures are not isomorphous. The paper concludes with a discussion of the figure of merit FN for pseudosymmetric structures. It is suggested that two figures of merit be reported. The first should be the standard one using either all measured reflections or just the first 30. The proposed second figure of merit does not include any superlattice reflections. These superlattice reflections tend to be very weak, resulting in a low completeness factor and relatively large error in the measurement of their position. This effect produces an unrealistically low value of the standard figure of merit. By including only “main” reflections, i.e., those reflections that are common to both the low-symmetry and high-symmetry parent phase (if it exists), a much better estimate of the quality of the fitting of the measured diffraction pattern is obtained.

scholarly journals Исследование этапов превращения кремния в карбид кремния в процессе атомного замещения методами полного внешнего отражения рентгеновских лучей и рентгеновской дифрактомерии

2022 ◽  
Vol 64 (3) ◽  
pp. 326
Author(s):  
С.А. Кукушкин ◽  
А.В. Осипов ◽  
Е.В. Осипова ◽  
В.М. Стожаров
Keyword(s):  
Structural Quality ◽  
Total External Reflection ◽  
X Rays ◽  
Reflection Method ◽  
X Ray Diffraction ◽  
Modified Technique ◽  
Substitution Method ◽  
X Ray ◽  
Sic Films

X-ray diffraction and total external reflection of X-rays (X-ray reflectometry) methods were used to study the successive stages of synthesis of epitaxial SiC films on Si (100) X-ray diffraction and total external X-ray reflection (XRD) methods were used to study successive stages of synthesis of epitaxial SiC films on Si (100) surfaces, (110) and (111) surfaces by the atom substitution method. The data on the transformation evolution of (100) surfaces were studied, (110) and (111) Si, into SiC surfaces. A comparative analysis of the X-ray structural quality of the SiC layers grown on Si by the atom substitution method with the quality of SiC layers grown by Advanced Epi by the standard CVD method. A modified technique for the total outer X-ray reflection method, based on measurements of the intensity of the reflected X-rays using a special parabolic mirror. It is shown that the method of total external reflection method makes it possible to obtain important information about the degree of surface roughness of SiC layers, the evolution of their crystal structure and plasmon energy in the process of Si to SiC conversion.

Structural and Magnetic Properties of Co50 ± x Pt50 ± x Thin Films Prepared by Mbe Co-Evaporation on (001) MgO Substrate at Various Temperatures

1998 ◽  
Vol 517 ◽  
Author(s):  
V. Parasote ◽  
M.-C. Cadevwlle ◽  
V. Pierron-Bohnes ◽  
W. Grange
Keyword(s):  
Magnetic Properties ◽  
Linear Increase ◽  
Anisotropy Energy ◽  
Structural Quality ◽  
Main Peak ◽  
X Ray Diffraction ◽  
Thermally Activated ◽  
Theoretical Predictions ◽  
Structural And Magnetic Properties

AbstractStructural and magnetic properties of Co50 ± x Pt50± x films 25-50 nm thick, prepared by molecular beam epitaxy onto a Pt buffer grown on MgO (001) substrate have been investigated. A series of 3 samples with different compositions (x = 6, 0, -6) was grown at 800 K on a 10 nm thick Pt buffer and another series of 5 samples of equiatomic composition was prepared at various growth temperatures (390 K≤ TG≤ 780 K) on a Pt buffer 4 nm thick. X-ray diffraction and TEM studies show the presence of grains with [111] and [002] orientations, the [002] grains being a mixture of the tetragonal L10 ordered phase and of the fcc disordered one. Both the thickness of the buffer layer and the deposition temperature are determinant parameters of the structural quality of the films and of the degree of long range order (LRO). An apparent LRO parameter (ηapp) is deduced from the superstructure and main peak intensity ratio. Its increase with the growth temperature is described through a thermally activated model that yields a small activation energy of 0.28 eV, illustrating the role played by both surface diffusion and surface interactions in building the L10 compound in agreement with theoretical predictions. An average uniaxial magnetocrystalline anisotropy energy (Kuav) is deduced from the magnetization curves measured by a SQUID. The anisotropy energy of the [002] grains (Ku002) is deduced, assuming a linear relationship between the anisotropies and the phase percentages. One observes a continuous but not linear increase of Ku002 with ηapp.

Study of the structural quality of heteroepitaxial silicon-on-sapphire structures by high-resolution X-ray diffraction, X-ray reflectivity, and electron microscopy

2014 ◽  
Vol 59 (3) ◽  
pp. 315-322 ◽  
Author(s):  
A. E. Blagov ◽  
A. L. Vasiliev ◽  
A. S. Golubeva ◽  
I. A. Ivanov ◽  
O. A. Kondratev ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
X Ray

INFLUENCE OF Al MONOLAYERS ON THE PROPERTIES OF AlN LAYERS ON Si (111)

2009 ◽  
Vol 16 (01) ◽  
pp. 99-103 ◽  
Author(s):  
L. S. CHUAH ◽  
Z. HASSAN ◽  
H. ABU HASSAN
Keyword(s):  
Buffer Layers ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
X Ray ◽  
Flat Surfaces ◽  
Gan On Si ◽  
Aln Buffer ◽  
Xrd Techniques ◽  
Substrate Temperatures

High-quality aluminum nitride ( AlN ) layers with full width at half maximum (FWHM) values of 11 arcmin were grown by plasma-assisted molecular-beam epitaxy on Si (111) substrates. AlN nucleation layers are being investigated for the growth of GaN on Si . Growth using AlN buffer layers leads to Al -polar films, with surfaces strongly dependent on the flux conditions used. Flat surfaces can be obtained by growing as Al -rich as possible, although Al droplets tend to form. Before starting the AlN growth, a few monolayers of Al are deposited on the substrate to avoid the formation of Si 3 N 4. X-ray diffraction (XRD) techniques were employed to determine the surface and structural quality of the layers. XRD revealed that monocrystalline AlN was obtained. Best AlN films were obtained at high substrate temperatures (875°C) and III/V ratios close to stoichiometry.

scholarly journals Lead potassium niobate thin films grown by Pulsed Laser Deposition

2016 ◽  
Vol vol1 (1) ◽  
Author(s):  
Billal Allouche ◽  
Yaovi Gagou ◽  
M. El Marssi
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Potassium Niobate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Deposition Parameters ◽  
Out Of Plane

By pulsed laser deposition, lead potassium niobate Pb2KNb5O15 was grown on (001) oriented Gd3Ga5O12 substrate using a platinum buffer layer. The PKN thin films were characterized by X-Ray diffraction and Scanning Electron Microscopy (SEM). The dependence of their structural properties as a function of the deposition parameters was studied. It has been found that the out of plane orientation of PKN film depends on the oxygen pressure used during the growth. Indeed, PKN thin film is oriented [001] for low pressure and is oriented [530] for high pressure. For these two orientations, the crystalline quality of PKN film was determined using omega scans.

High Resolution X-ray Diffraction of GaN Grown on Sapphire Substrates

1996 ◽  
Vol 449 ◽  
Author(s):  
A. Saxler ◽  
M. A. Capano ◽  
W. C. Mitchel ◽  
P. Kung ◽  
X. Zhang ◽  
...  
Keyword(s):  
Metalorganic Chemical Vapor Deposition ◽  
Reciprocal Lattice ◽  
Chemical Vapor ◽  
Lattice Points ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Primary Mechanism

ABSTRACTX-ray rocking curves are frequently used to assess the structural quality of GaN thin films. In order to understand the information given by the line shape, we need to know the primary mechanism by which the curves are broadened. The GaN films used in this study were grown by low pressure metalorganic chemical vapor deposition (MOCVD) on (00•1) sapphire substrates. GaN films with both broad and very narrow (open detector linewidth of 40 arcseconds for the (00•2) GaN reflection) rocking curves are examined in this work. Reciprocal space maps of both symmetric and asymmetric reciprocal lattice points are used to determine that the cause of the broadening of GaN rocking curves is a limited in-plane coherence length.

Growth of Well-Aligned ZnO Nanorods Using AuGe Catalyst by Vapor Phase Transportation

2006 ◽  
Vol 6 (11) ◽  
pp. 3624-3627
Author(s):  
S. Y. Ha ◽  
M. N. Jung ◽  
S. H. Park ◽  
H. J. Ko ◽  
H. Ko ◽  
...  
Keyword(s):  
Deep Level ◽  
Zno Nanorods ◽  
Horizontal Tube ◽  
Deep Level Emission ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Uv Emission ◽  
Tilting Angle

Well-aligned ZnO nanorods have been achieved using new alloy (AuGe) catalyst. Zn powder was used as a source material and it was transported in a horizontal tube furnace onto an AuGe deposited Si substrates. The structural and optical properties of ZnO nanorods were characterized by scanning electron microscopy, high resolution X-ray diffraction, and photoluminescence. ZnO nanorods grown at 650 °C on 53 nm thick AuGe layer show uniform shape with the length of 8±0.5 μm and the diameter of 150±5 nm. Also, the tilting angle of ZnO nanorods (±5.5°) is confirmed by HRXRD. High structural quality of the nanorods is conformed by the photoluminescence measurement. All samples show strong UV emission without considerable deep level emission. However, weak deep level emission appears at high (700 °C) temperature due to the increase of oxygen desertion.

Fabrication Of La0.7Sr0.3MnO3/La0.5Sr0.5CoO3/La0.7Sr0.3MnO3 Heterostructures for Spin Valve Applications

1997 ◽  
Vol 494 ◽  
Author(s):  
M. C. Robson ◽  
S. B. Ogale ◽  
R. Godfrey ◽  
T. Venkatesan ◽  
M. Johnson ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Spin Valve ◽  
Ferromagnetic Material ◽  
Perovskite Oxide ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
Metallic Oxide ◽  
Ferromagnetic Layers ◽  
Double Hysteresis Loop

ABSTRACTEpitaxial growth of oxide heterostructures, which may be utilized in spin valve applications, has been demonstrated. The heterostructures consist of two ferromagnetic layers separated by a nonmagnetic metallic interlayer. The ferromagnetic material used is the manganese perovskite oxide, La0.7Sr0.3MnO3, while the metallic oxide interlayer is La0.5Sr0.5CoO3. X-ray diffraction spectra demonstrate the high structural quality of the heterostructures. The magnetization of the heterostructure as a function of magnetic field measured at room temperature yields a double hysteresis loop that is characteristic of this type of spin valve structure. The behavior of this double hysteresis loop is also examined as a function of the metallic interlayer thickness.

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