Rowth of Y-CUT LiNbO3 Layers on (1102) Al2O3

1992 ◽  
Vol 263 ◽  
Author(s):  
H. Robinson ◽  
H.J. Milledge ◽  
C.W. Pitf
Keyword(s):  
Radio Frequency ◽  
X Ray Diffraction ◽  
Optical Modulators ◽  
X Ray ◽  
Monolithically Integrated ◽  
Radio Frequency Sputtering ◽  
Vicinal Substrate ◽  
Diffraction Patterns ◽  
Substrate Surfaces ◽  
Heteroepitaxial Layers

ABSTRACTIt has been found that y-cut LiNbO3 heteroepitaxial layers of good quality (as determined from X-ray diffraction patterns) can be obtained by radio frequency sputtering on noncrystallographic (vicinal) substrate surfaces approximating (1102) of Al2O3, in accord with the results concerning (100) Si growth on A12O3.Such material may find application in optical modulators monolithically integrated on to silicon-on-sapphire (SOS) circuits.

Effect of thermal annealing in a-InxGa1–xN films prepared by reactive RF-sputtering

2014 ◽  
Vol 92 (7/8) ◽  
pp. 943-946 ◽  
Author(s):  
Toshimasa Suzuki ◽  
Ruichi Katayama ◽  
Shun Hibino ◽  
Yoshinori Kato ◽  
Fumitaka Ohashi ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Room Temperature ◽  
Rf Sputtering ◽  
Large Change ◽  
Dark Conductivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radio Frequency Sputtering ◽  
Diffraction Patterns ◽  
Composition Ratios

We deposited amorphous indium gallium nitride (a-InxGa1–xN) films at room temperature by reactive radio frequency sputtering with GaN and InN targets and investigated the change of their properties from thermal annealing at annealing temperatures, Ta, below 200 °C. A large change in the indium and nitrogen composition ratios was not observed by thermal annealing at a Ta below 200 °C. In the X-ray diffraction patterns of the films annealed at a Ta below 200 °C, no perceivable peaks assigned to crystalline InxGa1–xN were found. The photoconductivty, σp, increased with an increase in Ta. On the other hand, the increase of the dark conductivity, σd, was very small with an increase in Ta below 200 °C. As a result, the photosensitivity, σp/σd, increased from 252 to 2500 by thermal annealing at a Ta of 200 °C.

MgO Thin Film Growth on Si(001) by Radio-Frequency Sputtering Method

2020 ◽  
Vol 20 (12) ◽  
pp. 7530-7534 ◽  
Author(s):  
Jitendra Pal Singh ◽  
Manish Kumar ◽  
Weon Cheol Lim ◽  
Hyun Hwi Lee ◽  
Young Mi Lee ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Annealing Temperature ◽  
Film Growth ◽  
Rf Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radio Frequency Sputtering ◽  
Crystalline Films ◽  
Local Electronic Structure ◽  
X Ray Absorption

Herein, sputtering duration and annealing temperature effects on the structure and local electronic structure of MgO thin films were studied using synchrotron radiation based X-ray diffraction and X-ray absorption spectroscopic investigations. These films were grown at substrate temperature of 350 °C by varying sputtering duration from 25 min to 324 min in radio frequency (RF) sputtering method followed by post-deposition annealing at 400, 600 and 700 °C for 3 h. These films were amorphous upto certain sputtering durations, typically upto 144 min and attains crystallization thereafter. This kind of behavior was observed at all annealing temperature. The textured coefficient of crystalline films envisaged that the orientation was affected by annealing temperature. Coordination of Mg2+ ions was more distorted in amorphous films compared to crystalline films. Moreover, onset of molecular oxygen are absorbed at low annealing temperature on these films.

scholarly journals Formation of various-axes-oriented wurtzite nuclei and enlargement of the a-axis-oriented region in AlFeN films deposited on Si(100) substrates

2021 ◽  
Author(s):  
Saki Imada ◽  
Toshiyuki Isshiki ◽  
Nobuyuki Tatemizo ◽  
Koji Nishio ◽  
Shuichi Mamishin ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Growth Process ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radio Frequency Sputtering ◽  
Oriented Region

Wurtzite AlN films with high Fe concentrations were deposited on Si(100) substrates using radio-frequency sputtering, and the growth process was investigated. X-ray diffraction (XRD) analyses with parallel incident X-rays showed...

scholarly journals Structural and Optical Changes of Undoped GaN Layers Grown via Radio-frequency Magnetron Sputtering Obtained from GaN Powders

2019 ◽  
Vol 4 (2) ◽  
pp. 59-63
Author(s):  
Erick Gastellóu ◽  
Crisoforo Morales ◽  
Godofredo García ◽  
Rafael García ◽  
Gustavo Alonso Hirata ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Radio Frequency ◽  
Crystal Size ◽  
Radio Frequency Magnetron ◽  
Radio Frequency Magnetron Sputtering ◽  
X Ray Diffraction ◽  
Homogeneous Surface ◽  
X Ray ◽  
Significant Difference ◽  
Diffraction Patterns

Undoped GaN layers were grown via radio-frequency magnetron sputtering, using a target manufactured with undoped GaN powders. Where the GaN powders were sintetized by nitridation of metallic gallium at 1000 °C in ammonia flow for two hours. X-ray diffraction patterns demonstrated that there are not a significant difference between the diffraction angles of the GaN powders and the GaN layers. The x-ray diffraction patterns for the GaN powders showed narrow peaks with a crystal size of 41 nm, while the GaN layers showed broad peaks with a crystal size of 7.7 nm. Scanning electron microscopy micrographs demonstrated the formation of crystals of irregular size with an average length of 1.56 μm for the GaN powders, while a homogeneous surface morphology with a thickness of 6.6 μm for the GaN layers was observed. Photoluminescence spectra showed a high emission at 3.49 eV (355.13 nm) for the GaN powders and an emission band energy located at 3.42 eV (361.54 nm) for the GaN layers, both emission bands were related to the band-to-band transition for the GaN. Raman spectra for the GaN powders showed the A1(TO), E1(TO), and E2(High) classical vibration modes. The GaN layers only showed the A1(TO) mode.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

Infrared spectroscopic study of the YPO4-YCrO4 system

1985 ◽  
Vol 50 (10) ◽  
pp. 2139-2145
Author(s):  
Alexander Muck ◽  
Eva Šantavá ◽  
Bohumil Hájek
Keyword(s):  
Spectroscopic Study ◽  
Infrared Spectra ◽  
Point Of View ◽  
Mixed Crystals ◽  
Crystal Symmetry ◽  
Infrared Spectroscopic Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Spectroscopic ◽  
Diffraction Patterns

The infrared spectra and powder X-ray diffraction patterns of polycrystalline YPO4-YCrO4 samples are studied from the point of view of their crystal symmetry. Mixed crystals of the D4h19 symmetry are formed over the region of 0-30 mol.% YPO4 in YCrO4. The Td → D2d → D2 or C2v(GS eff) correlation is appropriate for both PO43- and CrO43- anions.

scholarly journals Deep learning for visualization and novelty detection in large X-ray diffraction datasets

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Lars Banko ◽  
Phillip M. Maffettone ◽  
Dennis Naujoks ◽  
Daniel Olds ◽  
Alfred Ludwig
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
Artificial Intelligence ◽  
Deep Learning ◽  
Novelty Detection ◽  
Structural Similarity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Post Hoc

AbstractWe apply variational autoencoders (VAE) to X-ray diffraction (XRD) data analysis on both simulated and experimental thin-film data. We show that crystal structure representations learned by a VAE reveal latent information, such as the structural similarity of textured diffraction patterns. While other artificial intelligence (AI) agents are effective at classifying XRD data into known phases, a similarly conditioned VAE is uniquely effective at knowing what it doesn’t know: it can rapidly identify data outside the distribution it was trained on, such as novel phases and mixtures. These capabilities demonstrate that a VAE is a valuable AI agent for aiding materials discovery and understanding XRD measurements both ‘on-the-fly’ and during post hoc analysis.

scholarly journals Simultaneous Multi-Bragg Peak Coherent X-ray Diffraction Imaging

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 312
Author(s):  
Florian Lauraux ◽  
Stéphane Labat ◽  
Sarah Yehya ◽  
Marie-Ingrid Richard ◽  
Steven J. Leake ◽  
...  
Keyword(s):  
Bragg Reflection ◽  
Volume Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Substrate ◽  
In Series ◽  
Diffraction Imaging ◽  
Diffraction Patterns ◽  
Lattice Planes ◽  
Oriented Parallel

The simultaneous measurement of two Bragg reflections by Bragg coherent X-ray diffraction is demonstrated on a twinned Au crystal, which was prepared by the solid-state dewetting of a 30 nm thin gold film on a sapphire substrate. The crystal was oriented on a goniometer so that two lattice planes fulfill the Bragg condition at the same time. The Au 111 and Au 200 Bragg peaks were measured simultaneously by scanning the energy of the incident X-ray beam and recording the diffraction patterns with two two-dimensional detectors. While the former Bragg reflection is not sensitive to the twin boundary, which is oriented parallel to the crystal–substrate interface, the latter reflection is only sensitive to one part of the crystal. The volume ratio between the two parts of the twinned crystal is about 1:9, which is also confirmed by Laue microdiffraction of the same crystal. The parallel measurement of multiple Bragg reflections is essential for future in situ and operando studies, which are so far limited to either a single Bragg reflection or several in series, to facilitate the precise monitoring of both the strain field and defects during the application of external stimuli.

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