X-ray-diffraction measurements from imperfect GaAs crystals: Evidence for near-surface defects

1990 ◽  
Vol 42 (8) ◽  
pp. 5093-5099 ◽  
Author(s):  
R. Bloch ◽  
D. Bahr ◽  
J. Olde ◽  
L. Brügemann ◽  
W. Press
Keyword(s):  
Surface Defects ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray

Detection of a metallic glass layer by x-ray diffraction

1986 ◽  
Vol 1 (5) ◽  
pp. 629-634 ◽  
Author(s):  
J.W. McCamy ◽  
M.J. Godbole ◽  
A.J. Pedraza ◽  
D.H. Lowndes
Keyword(s):  
Target Material ◽  
Amorphous Layer ◽  
Glass Layer ◽  
X Rays ◽  
Average Thickness ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Integrated Intensity ◽  
Thickness Measurements

A simple, precise method for obtaining the average thickness of an amorphous layer formed by any surface treatment has been developed. The technique uses an x-ray diffractoeter to measure the reduction in the integrated intensity of several diffracted x-ray lines due to the near surface amorphous layer. The target material for generation of x rays is selected so that the emitted x rays are strongly absorbed by the specimen. This method permits thickness measurements down to ∼ 100 nm. It has been tested on a specimen of Fe80B20 on which an amorphous layer was produced by pulsed XeCl (308 nm) laser irradiation; the amorphous layer thickness was found to be 1.34 (∼0.1) um.

Synchrotron X-Ray Study of the Structure of Silicon During Pulsed Laser Processing

1981 ◽  
Vol 4 ◽  
Author(s):  
B. C. Larson ◽  
C. W. White ◽  
T. S. Noggle ◽  
J. F. Barhorst ◽  
D. Mills
Keyword(s):  
Laser Annealing ◽  
Pulsed Laser ◽  
Temperature Profiles ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Near Surface ◽  
X Ray ◽  
Pulsed Laser Annealing ◽  
Pulsed Laser Processing ◽  
Thermal Melting

ABSTRACTSynchrotron x-ray pulses have been used to make nanosecond resolution time-resolved x-ray diffraction measurements on silicon during pulsed laser annealing. Thermal expansion analysis of near-surface strains during annealing has provided depth dependent temperature profiles indicating >1100°C temperatures and diffraction from boron implanted silicon has shown evidence for near-surface melting. These results are in qualitative agreement with the thermal melting model of laser annealing.

scholarly journals The First Find of Cr2O3 Eskolaite Associated with Marble-Hosted Ruby in the Southern Urals and the Problem of Al and Cr Sources

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 101
Author(s):  
Aleksander Kissin ◽  
Irina Gottman ◽  
Sergei Sustavov ◽  
Valery Murzin ◽  
Daria Kiseleva
Keyword(s):  
Granite Gneiss ◽  
Southern Urals ◽  
X Ray Diffraction ◽  
The Southern Urals ◽  
Near Surface ◽  
X Ray ◽  
Gneiss Domes ◽  
Electron Probe Microanalyzer ◽  
Formation Zone ◽  
First Time

The results of the study of eskolaite associated with marble-hosted ruby found for the first time in the Kuchinskoe occurrence (Southern Urals) are presented. Here, eskolaite was located on the surface and near-surface regions of ruby crystals. Eskolaite diagnostics was confirmed by powder X-ray diffraction (URS-55). The morphology and chemical composition of eskolaite and associated ruby was studied using a JSM-6390LV scanning electron microscope and a Cameca SX 100 electron probe microanalyzer. The eskolaite crystals were hexagonal and tabular, up to 0.2 mm in size. Ruby mineralization was formed during prograde and retrograde dynamothermal metamorphism. The eskolaite associated with the prograde stage ruby contained Al2O3 (9.1–23.62 wt %), TiO2 (0.52–9.66 wt %), V2O3 (0.53–1.54 wt %), FeO (0.03–0.1 wt %), MgO (0.05–0.24 wt %), and SiO2 (0.1–0.21 wt %). The eskolaite associated with the retrograde stage ruby was distinguished by a sharp depletion in Ti and contained Al2O3 (12.25–21.2 wt %), TiO2 (0.01–0.07 wt %), V2O3 (0.32–1.62 wt %), FeO (0.01–0.08 wt %), MgO (0.0–0.48 wt %), and SiO2 (0.01–0.1 wt %). The associated rubies contained almost equal amounts of Cr2O3 (2.36–2.69 wt %) and were almost free from admixtures. The identification of the eskolaite associated with the marble-hosted rubies from the Kuchinskoe occurrence is a new argument in favor of introduction of Al and Cr into the mineral formation zone. The mineralization was localized in the metamorphic frame of the granite gneiss domes and was formed synchronously with them.

scholarly journals Crystal structure of propionitrile (CH3CH2CN) determined using synchrotron powder X-ray diffraction

2020 ◽  
Vol 27 (1) ◽  
pp. 212-216
Author(s):  
Helen E. A. Brand ◽  
Qinfen Gu ◽  
Justin A. Kimpton ◽  
Rebecca Auchettl ◽  
Courtney Ennis
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Solar System ◽  
Infrared Spectra ◽  
Lower Stratosphere ◽  
Computational Modelling ◽  
Outer Solar System ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray

The structure and thermal expansion of the astronomical molecule propionitrile have been determined from 100 to 150 K using synchrotron powder X-ray diffraction. This temperature range correlates with the conditions of Titan's lower stratosphere, and near surface, where propionitrile is thought to accumulate and condense into pure and mixed-nitrile phases. Propionitrile was determined to crystallize in space group, Pnma (No. 62), with unit cell a = 7.56183 (16) Å, b = 6.59134 (14) Å, c = 7.23629 (14), volume = 360.675 (13) Å3 at 100 K. The thermal expansion was found to be highly anisotropic with an eightfold increase in expansion between the c and b axes. These data will prove crucial in the computational modelling of propionitrile–ice systems in outer Solar System environments, allowing us to simulate and assign vibrational peaks in the infrared spectra for future use in planetary astronomy.

Relation between grazing incident X-ray diffraction and surface defects in silicon doped GaAs

2010 ◽  
Vol 405 (9) ◽  
pp. 2185-2188
Author(s):  
J.A. Villada ◽  
S. Jiménez-Sandoval ◽  
M. López-López ◽  
L. Baños ◽  
M.E. Rodríguez-García
Keyword(s):  
Surface Defects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicon Doped

X-ray diffraction from perfect silicon crystals distorted by surface acoustic waves

2000 ◽  
Vol 33 (4) ◽  
pp. 1019-1022 ◽  
Author(s):  
R. Tucoulou ◽  
R. Pascal ◽  
M. Brunel ◽  
O. Mathon ◽  
D. V. Roshchupkin ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Acoustic Waves ◽  
Crystal Surface ◽  
Source Region ◽  
Surface Acoustic Waves ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Near Surface ◽  
X Ray

High-resolution X-ray diffraction measurements were carried out on ZnO/Si devices under surface acoustic wave excitation and revealed some very clear satellite diffraction peaks that are obtained from the sinusoidal modulation of the near-surface region. This experiment shows that the propagation of a Rayleigh surface acoustic wave in a perfect crystal acts as a dynamical diffraction grating. The variation of the acoustic velocity has been followed across the crystal surface from the acoustic source region (beneath the ZnO film) to the far field region (not covered by the ZnO film).

Effect of Detector Width and Peak Location Technique on Residual Stress Determination in Case of Work-Hardened Materials

2006 ◽  
Vol 524-525 ◽  
pp. 755-760 ◽  
Author(s):  
M. Belassel ◽  
Eliane Bocher ◽  
J. Pineault
Keyword(s):  
Residual Stress ◽  
Surface Treatment ◽  
Work Hardening ◽  
Peak Position ◽  
X Ray Diffraction ◽  
Analytical Treatment ◽  
Near Surface ◽  
X Ray ◽  
Treatment Processes ◽  
High Level

To enhance the fatigue resistance of mechanical components, different surface treatment processes are often applied to put the near surface layer into compression. Surface treatment processes are typically associated with deformation and work-hardening of the material. When applying x-ray diffraction techniques to the characterization of such surfaces, the work-hardening will cause the x-ray diffraction peak width to increase. When peak widths reach high values, the peak tail may extend beyond the active area or window of the multichannel x-ray detector, in which case the peak is truncated. Subsequent analytical treatment of broad diffraction peaks is troublesome and advanced numerical methods are required to accurately determine the peak position. The following work indicates that when a wider detector is used it is possible to collect the full, non-truncated peak, determine the peak position with a high level of confidence and subsequently, to calculate the residual stress with much improved repeatability and reproducibility.

Characterization of Reactive Ion Etch Damage in GaAs by Triple Crystal X-Ray Diffraction

1993 ◽  
Vol 324 ◽  
Author(s):  
Victor S. Wang ◽  
Richard J. Matyi ◽  
Karen J. Nordheden
Keyword(s):  
Bias Voltage ◽  
Diffuse Scattering ◽  
Reciprocal Lattice ◽  
Surface Region ◽  
Perfect Crystal ◽  
X Ray Diffraction ◽  
Reciprocal Lattice Point ◽  
Near Surface ◽  
X Ray ◽  
Imperfect Crystal

AbstractTriple crystal x-ray diffraction (TCXD) is a non-destructive structural characterization tool capable of the separation and direct observation of the dynamic (perfect crystal) and the kinematic (imperfect crystal) components of the total intensity diffracted by a crystal. Specifically, TCXD can be used to measure the magnitude of the diffuse scattering arising from defects in the crystal structure in the immediate vicinity of a reciprocal lattice point. In this study, the effects of BC13 reactive ion etching (RIE) on the near-surface region of GaAs were investigated by analyzing the changes in the diffuse scattering using both the symmetric 004 reflection as well as the highly asymmetric and more surface sensitive 113 reflection. While the results from the 004 reflections revealed little difference between the unetched and the BC13-etched samples, maps of the diffracted intensity around the 113 reflections showed an unexpected and reproducible decrease in the extent of the diffuse scattering in the transverse direction (perpendicular to the < 113 > direction) as the RIE bias voltage was increased. This decrease suggests that the degree of etch damage induced in the GaAs near-surface region is reduced with increasing bias voltage and ion energy. Additionally, the symmetry and orientation of the kinematic scattering was altered. Possible mechanisms for these results willbe discussed.

Microstructure and Oxidation of a Cast Nickel Aluminide Alloy

2002 ◽  
Vol 753 ◽  
Author(s):  
D. Y. Lee ◽  
M. L. Santella ◽  
I. M. Anderson ◽  
G. M. Pharr
Keyword(s):  
Nickel Aluminide ◽  
Volume Fraction ◽  
Surface Region ◽  
Oxidation Products ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Multivariate Statistical ◽  
Near Surface ◽  
X Ray ◽  
Spectrum Imaging

ABSTRACTSpecimens of the cast Ni3Al alloy IC221M were annealed in air at 900°C to examine the effects of oxidation and thermal aging on the microstructure. The alloy is comprised of a dendritically solidified γ-γ′ matrix containing γ+Ni5Zr eutectic colonies in the interdendritic regions. Microstructures of aged specimens were examined by optical microscopy and energy dispersive X-ray (EDX) spectrum imaging in the scanning electron microscope (SEM). Two primary changes in the microstructures were observed: (1) there is considerable homogenization of the cast microstructures with aging, and (2) the volume fraction of the γ+Ni5Zr eutectic decreases. Oxidation products were identified using x-ray diffraction and EDX spectrum imaging with multivariate statistical analysis (MSA). During the initial stages of oxidation, the first surface oxide to form is mostly NiO with small amounts of Cr2O3, ZrO2, NiCr2O4, and θ-Al2O3. Initially, oxidation occurs primarily in the interdendritic regions due to microsegregation of alloying elements during casting. With further aging, a continuous film of α-Al2O3 forms immediately beneath the surface that eventually evolves into a double layer of α-Al2O3 and NiAl2O4. Although these oxides are constrained to the near surface region, others penetrate to greater depths facilitated by oxidation of the γ+Ni5Zr eutectic colonies. These oxides appear in the microstructure as long, thin spikes of ZrO2 surrounded by a thin sheath of Al2O3.

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