White beam synchrotron topography and gamma -ray diffractometry characterization of the crystalline quality of single-grain superalloys: influence of the solidification conditions

1993 ◽  
Vol 26 (4A) ◽  
pp. A50-A52 ◽  
Author(s):  
D Bellet ◽  
P Bastie ◽  
J Baruchel
Keyword(s):  
Gamma Ray ◽  
Crystalline Quality ◽  
White Beam ◽  
Single Grain

Characterization of the crystalline quality of β-SiC formed by ion beam synthesis

2006 ◽  
Vol 249 (1-2) ◽  
pp. 851-855 ◽  
Author(s):  
S. Intarasiri ◽  
A. Hallén ◽  
T. Kamwanna ◽  
L.D. Yu ◽  
G. Possnert ◽  
...  
Keyword(s):  
Ion Beam ◽  
Crystalline Quality ◽  
Ion Beam Synthesis

scholarly journals Magnetic characterization of (001) and (111) Ni films epitaxially grown on MgO

2001 ◽  
Vol 674 ◽  
Author(s):  
R. A. Lukaszew ◽  
V. Stoica ◽  
R. Clarke
Keyword(s):  
Film Growth ◽  
Chemical Interaction ◽  
Hysteresis Loops ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Buffer Layers ◽  
Crystalline Quality ◽  
Silicon Substrates

ABSTRACTOne interesting application of epitaxial magnetic thin films is to use them as one of the electrodes in a spin-dependent tunneling junction, in order to use the magnetocrystalline anisotropy to define the required two states of the magnetization. [1] In our preliminary work, we prepared epitaxial magnetic films on copper buffer layers grown on silicon substrates. [2] The single crystalline quality of the films was particularly evident in the magnetization hysteresis loops, showing a sharp reversal at fairly high fields (120 Oe), when the samples were magnetized along the crystallographic easy axis. One technological disadvantage in this type of samples is the chemical interaction between the metallic layers and the silicon substrate.In order to explore the possibility of epitaxial magnetic films on less reactive substrates, we studied the growth on MgO substrates. We have shown that it is possible to obtain epitaxial (001) and (111) Ni films grown on MgO substrates. [3] In particular we observed that the crystalline quality of the films improved considerably after 10 nm of film growth. We will now present our studies on the magnetic properties of these films, particularly the azimuthal dependence of the magnetization reversal using MOKRE, correlating our finding with the structural characterization obtained with RHEED, STM and XRD.

The preparation and characterization of one-dimensional TiO2 nanostructure by hydrothermal method

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040024
Author(s):  
Lin Yu ◽  
Yuan-Yuan Xu ◽  
Jing Zhao ◽  
Jin Xiao ◽  
Wei-Long Xu
Keyword(s):  
Hydrothermal Method ◽  
Sintering Temperature ◽  
Oxide Semiconductor ◽  
Crystalline Quality ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
Physicochemical Stability ◽  
Potential Applications

Titanium dioxide ([Formula: see text]) is a kind of wide bandgap transparent metal oxide semiconductor and has shown great potential applications in photocatalysis, gas sensors and biomedical fields due to its superior properties, such as nontoxic, high photocatalytic efficiency and physicochemical stability. In this work, one-dimensional [Formula: see text] nanostructure was successfully synthesized by hydrothermal method. The morphology and crystalline quality of [Formula: see text] were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The results demonstrate that the structure of [Formula: see text] evolved from “flower-like” structure to nanowire with the acid concentration increment. The sintering temperature has an important effect on the structure and crystalline quality of [Formula: see text]. The crystalline quality of [Formula: see text] nanobelt was improved with the annealing temperature increment. When the sintering temperature increased to 1000[Formula: see text]C, the phase of [Formula: see text] would transfer from anatase to rutile.

Photoreflectance Characterization of Silicon Films on Insulator

1990 ◽  
Vol 188 ◽  
Author(s):  
Adriana Giordana ◽  
R. Glosser ◽  
Joseph G. Pellegrino ◽  
S. Qadri ◽  
M. E. Twigg ◽  
...  
Keyword(s):  
Silicon Layer ◽  
Sample Thickness ◽  
Silicon Films ◽  
Crystalline Quality ◽  
Silicon Structure

ABSTRACTPhotoreflectance (PR) was used to study crystalline quality and stress in silicon films on insulator. The position and amplitude of the 3.4 eV PR silicon structure was monitored for both MBE silicon on sapphire (SOS) and SIMOX structures. The SOS film thicknesses ranged from 6 to 4000 nm. The shift in energy of the 3.4 eV structure from its bulk position is dependent on the sample thickness and on the strain in the films. In the SIMOX case, the amplitude of the 3.4 eV PR signal provided information about the crystalline quality of the top silicon layer for a set of six samples, each one removed at a different step of a process involving three implantation-anneal cycles. In this case the PR signal appeared to deteriorate with the each cycle undergone by the samples. Further investigations are needed to resolve the discrepancy bet ween these SOS results and the ones obtained in an earlier set of measurements.

Structural and Morphological Characterization of 3C-SiC Films Grown on (111), (211) and (100) Silicon Substrates

2008 ◽  
Vol 600-603 ◽  
pp. 231-234 ◽  
Author(s):  
Marc Portail ◽  
M. Nemoz ◽  
Marcin Zielinski ◽  
Thierry Chassagne
Keyword(s):  
Flow Rate ◽  
Morphological Characterization ◽  
Crystalline Quality ◽  
Silicon Substrates ◽  
Interfacial Defects ◽  
Twin Defects ◽  
Sic Films

The structural and morphological modifications induced by the carbonization stage upon 3C-SiC heteroepitaxial films grown on (111) and (100) oriented silicon substrates have been investigated. The crystalline quality of the films is strongly dependent on the carbonization parameters (propane flow rate and duration of carbonization). The (111) heteroepitaxial films coalesce more rapidly and present a lower dependence on the carbonization conditions than (100) films. By comparing the evolution of the interfacial defects (voids) density with existing models, we show that this is related to the initial mechanisms occurring during the carbonization stage. The twin defects densities on (111), (100) and (211) films are also investigated and the role of the only carbonization stage on their formation is studied.

Growth and Characterization of GaAs-Based Heterostructures on Si By Mocvd

1988 ◽  
Vol 116 ◽  
Author(s):  
W. S. Hobson ◽  
S. J. Pearton ◽  
K. T. Short ◽  
K. S. Jones ◽  
S. M. Vernon ◽  
...  
Keyword(s):  
Surface Quality ◽  
Laser Annealing ◽  
Defect Density ◽  
Crystalline Quality ◽  
Si Substrates ◽  
Gaas On Si ◽  
Different Types

AbstractAbstract: Several different types of GaAs-AlGaAs heterostructures were grown on Si substrates by MOCVD. The defect density in as-grown samples (~108cm−2) was similar to that of GaAs layers grown directly on Si, and the crystalline quality of the material was observed to improve slightly with post-growth annealing at 900°C. We examined the diffusion of both Si and Zn dopants during this type of annealing and found only a small amount of redistribution of both species. Laser annealing of GaAs-on-Si was also examined as a method of reducing the defect density in the material - we observed substantial improvements in surface quality, but no change in sub-surface crystalline quality.

Characterization of crystalline quality of diamond films by Raman spectroscopy

1989 ◽  
Vol 55 (25) ◽  
pp. 2608-2610 ◽  
Author(s):  
M. Yoshikawa ◽  
G. Katagiri ◽  
H. Ishida ◽  
A. Ishitani ◽  
M. Ono ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Diamond Films ◽  
Crystalline Quality

Structure and Orientation of As Precipitates in LT-MBE Grown GaAs

1991 ◽  
Vol 49 ◽  
pp. 900-901 ◽  
Author(s):  
Alain Claverie ◽  
Zuzanna Liliental-Weber
Keyword(s):  
Transport Properties ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Low Temperatures ◽  
Lattice Parameter ◽  
Crystalline Quality ◽  
Insulating Properties ◽  
Lt Gaas

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.

Physicochemical and bacteriological characterization of hospital effluents and their impact on the environment

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Human Health ◽  
Fecal Coliforms ◽  
Chemical Pollution ◽  
Hospital Effluents ◽  
Biological Contaminants ◽  
Almost All ◽  
Direct Discharge ◽  
Significant Chemical

Liquid effluents discharged by hospitals may contain chemical and biological contaminants whose main source is the different substances used for the treatment of patients. This type of rejection can present a sanitary potentially dangerous risk for human health and can provoke a strong degradation of diverse environmental compartments mainly water and soils. The present study focuses on the quality of the liquid effluents of Hassani Abdelkader’s hospital of Sidi Bel-Abbes (West of Algeria). The results reveal a significant chemical pollution (COD: 879 mgO2/L, BOD5: 850 mgO2/L, NH4+ : 47.9 mg/l, NO2- : 4.2 mg/l, NO3- : 56.8 mg/l with respect to WHO standard of 90 mgO2/L, 30 mgO2/L, 0.5 mg/l, 1 mg/l and 1 mg/l respectively). However, these effluents are biodegradable since the ratio COD/BOD5 do not exceeded the value of 2 in almost all samples. The presence of pathogen germs is put into evidence such as pseudomonas, the clostridium, the staphylococcus, the fecal coliforms and fecal streptococcus. These results show that the direct discharge of these effluents constitutes a major threat to human health and the environment.

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