scholarly journals Controllable CaF2 Nanosized Stripe Arrays on Si(001) Studied by X-ray and Electron Diffraction

Surfaces ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 97-105
Author(s):  
Sergey M. Suturin ◽  
Vladimir V. Fedorov ◽  
Alexander M. Korovin ◽  
Gleb A. Valkovskiy ◽  
Masao Tabuchi ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Atomic Layer ◽  
Grazing Incidence ◽  
High Energy ◽  
Reciprocal Space ◽  
X Rays ◽  
Reciprocal Space Mapping ◽  
Long Time ◽  
Fine Control ◽  
Oriented Parallel

Adding uniaxial in-plane anisotropy to the otherwise four-fold Si(001) surface has for a long time been known to be possible via epitaxial deposition of a single atomic layer of calcium fluoride (CaF2), which forms an array of micron-long (110) oriented parallel stripes when the substrate temperature during the growth is kept in the range of 700–800 °C. As shown in the present paper, a fine control over dimensions and periodicity of the stripe array is possible through the introduction of a two-stage growth process at which the (110) orientation of the fluorite layer is settled at the high-temperature nucleation stage, while the stripes of controllable dimensions are formed at the second stage. By varying the substrate temperature at the second growth stage in the range of 800–400 °C, the stripe arrays with a periodicity from above 30 nm to below 10 nm can be fabricated with the height variation changing accordingly. Such variability can be of use in the applications in which the striped fluorite surface is used to influence the anisotropy of other functional (e.g., magnetically ordered or organic) materials grown on top. While large CaF2 stripes can be easily characterized by direct space techniques such as atomic force microscopy, the study of the shape and in-plane correlation between the stripes of a much smaller size is most effectively achieved through the use of grazing incidence reciprocal space techniques applied in the present paper. The discussed universal approach to 3D reciprocal space mapping utilizing scattering of X-rays and high-energy electrons offers a complementary way to study samples with arrays of long and narrow one-dimensional stripes at their surface.

scholarly journals A look inside epitaxial cobalt-on-fluorite nanoparticles with three-dimensional reciprocal space mapping using GIXD, RHEED and GISAXS

2013 ◽  
Vol 46 (4) ◽  
pp. 874-881 ◽  
Author(s):  
S. M. Suturin ◽  
V. V. Fedorov ◽  
A. M. Korovin ◽  
G. A. Valkovskiy ◽  
S. G. Konnikov ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Crystal Lattice ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
High Energy ◽  
Space Mapping ◽  
Reciprocal Space ◽  
Face Centered Cubic ◽  
Reciprocal Space Mapping ◽  
X Ray

In this work epitaxial growth of cobalt on CaF2(111), (110) and (001) surfaces has been extensively studied. It has been shown by atomic force microscopy that at selected growth conditions stand-alone faceted Co nanoparticles are formed on a fluorite surface. Grazing-incidence X-ray diffraction (GIXD) and reflection high-energy electron diffraction (RHEED) studies have revealed that the particles crystallize in the face-centered cubic lattice structure otherwise non-achievable in bulk cobalt under normal conditions. The particles were found to inherit lattice orientation from the underlying CaF2 layer. Three-dimensional reciprocal space mapping carried out using X-ray and electron diffraction has revealed that there exist long bright 〈111〉 streaks passing through the cobalt Bragg reflections. These streaks are attributed to stacking faults formed in the crystal lattice of larger islands upon coalescence of independently nucleated smaller islands. Distinguished from the stacking fault streaks, crystal truncation rods perpendicular to the {111} and {001} particle facets have been observed. Finally, grazing-incidence small-angle X-ray scattering (GISAXS) has been applied to decouple the shape-related scattering from that induced by the crystal lattice defects. Particle faceting has been verified by modeling the GISAXS patterns. The work demonstrates the importance of three-dimensional reciprocal space mapping in the study of epitaxial nanoparticles.

On High-Resolution Reciprocal-Space Mapping with a Triple-Crystal Diffractometer for High-Energy X-rays

1998 ◽  
Vol 5 (2) ◽  
pp. 82-89 ◽  
Author(s):  
K. D. Liss ◽  
A. Royer ◽  
T. Tschentscher ◽  
P. Suortti ◽  
A. P. Williams
Keyword(s):  
High Resolution ◽  
High Energy ◽  
Space Mapping ◽  
Reciprocal Space ◽  
X Rays ◽  
Reciprocal Space Mapping

“Cartography” in 7-Dimensions at CHESS: Mapping of Structure in Real Space, Reciprocal Space, and Time Using High-Energy X-rays

2020 ◽  
Vol 33 (6) ◽  
pp. 11-16
Author(s):  
K. E. Nygren, ◽  
D. C. Pagan, ◽  
J. P. C. Ruff ◽  
E. Arenholz ◽  
J. D. Brock
Keyword(s):  
High Energy ◽  
Real Space ◽  
Reciprocal Space ◽  
X Rays ◽  
Space And Time

Epitaxial Ni nanoparticles on CaF2(001), (110) and (111) surfaces studied by three-dimensional RHEED, GIXD and GISAXS reciprocal-space mapping techniques

2017 ◽  
Vol 50 (3) ◽  
pp. 830-839 ◽  
Author(s):  
S. M. Suturin ◽  
V. V. Fedorov ◽  
A. M. Korovin ◽  
N. S. Sokolov ◽  
A. V. Nashchekin ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
High Energy ◽  
Reciprocal Space ◽  
Mapping Technique ◽  
Face Centered Cubic ◽  
X Ray ◽  
Cubic Lattice ◽  
Face Centered

The development of growth techniques aimed at the fabrication of nanoscale heterostructures with layers of ferroic 3dmetals on semiconductor substrates is very important for their potential usage in magnetic media recording applications. A structural study is presented of single-crystal nickel island ensembles grown epitaxially on top of CaF2/Si insulator-on-semiconductor heteroepitaxial substrates with (111), (110) and (001) fluorite surface orientations. The CaF2buffer layer in the studied multilayer system prevents the formation of nickel silicide, guides the nucleation of nickel islands and serves as an insulating layer in a potential tunneling spin injection device. The present study, employing both direct-space and reciprocal-space techniques, is a continuation of earlier research on ferromagnetic 3dtransition metals grown epitaxially on non-magnetic and magnetically ordered fluorides. It is demonstrated that arrays of stand-alone faceted nickel islands with a face-centered cubic lattice can be grown controllably on CaF2surfaces of (111), (110) and (001) orientations. The proposed two-stage nickel growth technique employs deposition of a thin seeding layer at low temperature followed by formation of the islands at high temperature. The application of an advanced three-dimensional mapping technique exploiting reflection high-energy electron diffraction (RHEED) has proved that the nickel islands tend to inherit the lattice orientation of the underlying fluorite layer, though they exhibit a certain amount of {111} twinning. As shown by scanning electron microscopy, grazing-incidence X-ray diffraction (GIXD) and grazing-incidence small-angle X-ray scattering (GISAXS), the islands are of similar shape, being faceted with {111} and {100} planes. The results obtained are compared with those from earlier studies of Co/CaF2epitaxial nanoparticles, with special attention paid to the peculiarities related to the differences in lattice structure of the deposited metals: the dual-phase hexagonal close-packed/face-centered cubic lattice structure of cobalt as opposed to the single-phase face-centered cubic lattice structure of nickel.

scholarly journals Design and Performance of the X-ray Polarimeter X-Calibur

2014 ◽  
Vol 03 (02) ◽  
pp. 1440008 ◽  
Author(s):  
M. Beilicke ◽  
F. Kislat ◽  
A. Zajczyk ◽  
Q. Guo ◽  
R. Endsley ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Detection Efficiency ◽  
Grazing Incidence ◽  
High Energy ◽  
X Rays ◽  
Field Orientation ◽  
Synchrotron Source ◽  
X Ray ◽  
And Performance ◽  
Detector Assembly

X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, neutron stars, and gamma-ray bursts. We designed, built and tested a X-ray polarimeter, X-Calibur, to be used in the focal plane of the balloon-borne InFOCμS grazing incidence X-ray telescope. X-Calibur combines a low-Z scatterer with a Cadmium Zinc Telluride (CZT) detector assembly to measure the polarization of 20–80 keV X-rays making use of the fact that polarized photons scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of ≃80%. The X-Calibur detector assembly is completed, tested, and fully calibrated. The response to a polarized X-ray beam was measured successfully at the Cornell High Energy Synchrotron Source. This paper describes the design, calibration and performance of the X-Calibur polarimeter. In principle, a similar space-borne scattering polarimeter could operate over the broader 2–100 keV energy band.

Indexation scheme for oriented molecular thin films studied with grazing-incidence reciprocal-space mapping

2007 ◽  
Vol 40 (4) ◽  
pp. 716-718 ◽  
Author(s):  
Detlef-M. Smilgies ◽  
Daniel R. Blasini
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Small Molecules ◽  
Organic Electronics ◽  
Grazing Incidence ◽  
Space Mapping ◽  
Reciprocal Space ◽  
Molecular Structures ◽  
Reciprocal Space Mapping ◽  
Mapping Scheme

Thin films of small molecules relevant to organic electronics applications often show a confusing degree of polymorphism. An effective reciprocal-space mapping scheme has been developed in order to find and index thin-film reflections which are related to previously known molecular structures. By method of elimination, thin-film reflections due to novel thin-film phases can thus be identified.

scholarly journals Reciprocal Space Mapping of Epitaxial Materials Using Position-Sensitive X-ray Detection

1994 ◽  
Vol 38 ◽  
pp. 201-213 ◽  
Author(s):  
S. R. Lee ◽  
B. L. Doyle ◽  
T. J. Drummond ◽  
J. W. Medernach ◽  
P. Schneider
Keyword(s):  
Space Mapping ◽  
Reciprocal Space ◽  
X Rays ◽  
X Ray Diffraction ◽  
Reciprocal Space Mapping ◽  
Rocking Curve ◽  
X Ray ◽  
Position Sensitive ◽  
Average Size ◽  
Short Time

Abstract Reciprocal space mapping can be efficiently carried out using a position-sensitive x-ray detector (PSD) coupled to a traditional double-axis diffractometer. The PSD offers parallel measurement of the total scattering angle of all diffracted x-rays during a single rocking-curve scan. As a result, a two-dimensional reciprocal space map can be made in a very short time similar to that of a one-dimensional rocking-curve scan. Fast, efficient reciprocal space mapping offers numerous routine advantages to the x-ray diffraction analyst. Some of these advantages arc the explicit differentiation of lattice strain from crystal orientation effects in strain-relaxed heteroepitaxial layers; the nondestructive characterization of the size, shape and orientation of nanocrystalline domains in ordered-alloy epilayers; and the ability to measure the average size and shape of voids in porous epilayers. Here, the PSD-based diffractometer is described, and specific examples clearly illustrating the advantages of complete reciprocal space analysis are presented.

Application of synchrotron-based reciprocal-space mapping at a fixed angular position to identification of crystal symmetry of Bi4Ti3O12epitaxial thin films

2011 ◽  
Vol 44 (2) ◽  
pp. 385-391 ◽  
Author(s):  
Osami Sakata ◽  
Takayuki Watanabe ◽  
Hiroshi Funakubo
Keyword(s):  
Azimuthal Angle ◽  
Angular Position ◽  
Chemical Vapor ◽  
Space Mapping ◽  
Reciprocal Space ◽  
Crystal Symmetry ◽  
Incidence Geometry ◽  
Organic Chemical ◽  
X Rays ◽  
Reciprocal Space Mapping

The crystal structures of Bi4Ti3O12epitaxial films with thicknesses of 50 and 3 nm were investigated using synchrotron-based diffraction. Films with (100)/(010) orientations (i.e.aandbdomains) were grown on TiO2(101) single crystals using metal–organic chemical vapor deposition. Synchrotron-based reciprocal-space mapping at a fixed angular position was applied to the determination of the crystal symmetry of the films. This method used a grazing-incidence geometry at a fixed azimuthal angle using 25 keV incident X-rays, which enabled the generation of a reciprocal-space map with a single X-ray exposure. The maps recorded about 120 and 30 diffraction spots from the 50 and 3 nm-thick samples, respectively. A two-dimensional 200 × 250 mm detector was used 133 mm downstream from the sample. The results revealed that both Bi4Ti3O12films had aB1a1 monoclinic structure or a lower crystal symmetry.

scholarly journals A multireflection and multiwavelength residual stress determination method using energy dispersive diffraction

2018 ◽  
Vol 51 (3) ◽  
pp. 732-745 ◽  
Author(s):  
Marianna Marciszko ◽  
Andrzej Baczmański ◽  
Manuela Klaus ◽  
Christoph Genzel ◽  
Adrian Oponowicz ◽  
...  
Keyword(s):  
Residual Stress ◽  
Synchrotron Radiation ◽  
Diffraction Method ◽  
Surface Region ◽  
Grazing Incidence ◽  
High Energy ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray Diffraction ◽  
Near Surface

The main focus of the presented work was the investigation of structure and residual stress gradients in the near-surface region of materials studied by X-ray diffraction. The multireflection method was used to measure depth-dependent stress variation in near-surface layers of a Ti sample (grade 2) subjected to different mechanical treatments. First, the multireflection grazing incidence diffraction method was applied on a classical diffractometer with Cu Kα radiation. The applicability of the method was then extended by using a white synchrotron beam during an energy dispersive (ED) diffraction experiment. An advantage of this method was the possibility of using not only more than one reflection but also different wavelengths of radiation. This approach was successfully applied to analysis of data obtained in the ED experiment. There was good agreement between the measurements performed using synchrotron radiation and those with Cu Kα radiation on the classical diffractometer. A great advantage of high-energy synchrotron radiation was the possibility to measure stresses as well as thea0parameter andc0/a0ratio for much larger depths in comparison with laboratory X-rays.

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