scholarly journals Enhancement of gas response of annealed ZnO film for hydrogen gas detection

2019 ◽  
Vol 12 (23) ◽  
pp. 73-79
Author(s):  
Thamir A.A. Hassan
Keyword(s):  
Room Temperature ◽  
Annealed Film ◽  
Hydrogen Gas ◽  
X Ray Diffraction ◽  
Zno Film ◽  
X Ray ◽  
Vacancy Model ◽  
Before And After ◽  
Gas Response ◽  
Hydrogen Gas Detection

  The mechanism of hydrogen (H2) gas sensor in the range of 50-200 ppm of RF-sputtered annealed zinc oxide (ZnO) and without annealing was studied. The X-ray Diffraction( XRD) results showed that the Zn metal was completely converted to ZnO with a polycrystalline structure. The I–V characteristics of the device (PT/ZnO/Pt) measured at room temperature before and after annealing at 450 oC for4h, from which a linear relationship has been observed. The sensors had a maximum response to H2 at 350 oC for annealing ZnO and showed stable behavior for detecting H2 gases in the range of 50 to 200 ppm. The annealed film exhibited higher response than the film without annealing.. The sensing mechanism was modeled according to the oxygen–vacancy model.

X-Ray Diffraction Studies on the Titanium-Nickel System

1962 ◽  
Vol 6 ◽  
pp. 74-84
Author(s):  
John V. Gilfrich
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Stoichiometric Composition ◽  
Physical Property ◽  
X Ray Diffraction ◽  
X Ray ◽  
Property Data ◽  
Before And After ◽  
Titanium Nickel ◽  
Physical Property Data

AbstractX-ray diffraction studies were made on the Ti–Ni system around the stoichiometric composition of the intermetallic compound TiNi to clarify some confusion which has existed about the phase diagram in this region, and to explain some anomalies in the physical properties of this material. Wrought and cast samples were examined at room temperature both before and after heat treatment and at temperatures both above and below ambient. The compound TiNi does exist at room temperature. The phase purity of the particular sample was found to be greatly affected by such factors as minor variations in composition, heat treatment, and method of sample preparation. Some confirming metallographlc and physical property data will also be presented.

Microstructure of Epitaxial Al(111)/Si(111) Films Studied by Synchrotron Grazing Incidence X-Ray Diffraction

1990 ◽  
Vol 202 ◽  
Author(s):  
H. H. Hung ◽  
K. S. Liang ◽  
C. H. Lee ◽  
T.-M. Lu
Keyword(s):  
Annealed Film ◽  
Grazing Incidence ◽  
Misfit Strain ◽  
Interfacial Structure ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Incommensurate Structure ◽  
Before And After ◽  
Beam Deposition

ABSTRACTWe report the results of our x-ray diffraction studies on epitaxial Al(111)/Si(111) films prepared by the partially ionized beam deposition technique. Significant changes were observed in intensity profiles for samples before and after annealing. In the in-plane radial scan of Al(220) peak, the shift of Bragg peak is shown due to misfit strain. A weak satellite is also observed which indicates a semicoherent interfacial structure of the annealed film with misfit dislocations. A possible picture of misfit-induced incommensurate structure of Al films is discussed.

Microstructure of Epitaxial Al(111)/Si(111) Films Studied by Synchrotron Grazing Incidence X-Ray Diffraction

1990 ◽  
Vol 208 ◽  
Author(s):  
H. H. Hung ◽  
K. S. Liang ◽  
C. H. Lee ◽  
T.-M. Lu
Keyword(s):  
Annealed Film ◽  
Grazing Incidence ◽  
Misfit Strain ◽  
Interfacial Structure ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Incommensurate Structure ◽  
Before And After ◽  
Beam Deposition

ABSTRACTWe report the results of our x-ray diffraction studies on epitaxial Al(lll)/Si(lll) films prepared by the partially ionized beam deposition technique. Significant changes were observed in intensity profiles for samples before and after annealing. In the in-plane radial scan of Al(220) peak, the shift of Bragg peak is shown due to misfit strain. A weak satellite is also observed which indicates a semicoherent interfacial structure of the annealed film with misfit dislocations. A possible picture of misfit-induced incommensurate structure of Al films is discussed.

LASER-INDUCED SELECTIVE CRYSTALLIZATION OF A-SiGe FILM

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4203-4206 ◽  
Author(s):  
XIYING MA ◽  
XUEKANG CHEN ◽  
GAN WU ◽  
JIANPING YANG ◽  
ZHANGXU LEI
Keyword(s):  
Room Temperature ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Nanometer Materials ◽  
Selective Crystallization ◽  
Treated Sample ◽  
Before And After ◽  
Two Peaks

Laser induced pattern crystallization technique with pulsed KrF excimer (248 nm) laser was used to irradiation amorphous SiGe films prepared by plasma-enhanced chemical vapor deposition (PECVD) on Si substrates. The surface of laser treated sample was investigated by scanning electron microscopy (SEM), it was found that the film irradiated by KrF excimer composed by well-shaped square periodicity embedded in the a-SiGe matrix, and in each square there are laser induced SiGe nanocrystals. The size of SiGe crystals was estimated to be about 10 nm. The samples were analyzed by X-ray diffraction, Raman spectroscopy and photoluminescence analysis before and after crystallization. The Raman spectrum shows strong Ge-Ge, Si-Ge, and Si-Si vibrations that agree with those of crystalline Si 1-x Ge x alloy. Strong PL with two peaks at 720 nm and 750 nm was observed at room temperature in the crystallized film, whereas the uncrystallized sample emits no peaks. These results indicate that nanometer SiGe alloy were formed and laser-induced technology is an efficient technique to produce nanometer materials.

scholarly journals Preparation of ZnO film on p-Si Substrate by Silar and Heterojunction Characteristics of p-Si/n-Zno

2011 ◽  
Vol 8 (1) ◽  
pp. 197-200 ◽  
Author(s):  
P. Mitra
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Reverse Current ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Si Substrate ◽  
Current Ratio ◽  
Axis Orientation ◽  
X Ray ◽  
Maximum Value

Zinc oxide (ZnO) thin films was deposited on p-silicon (Si) substrate from ammonium zincate bath following a chemical dipping technique called SILAR. Structural characterization by X-ray diffraction (XRD) indicates the formation of polycrystalline single phase ZnO with strong c-axis orientation. I-V characteristic of the p-Si/n-ZnO heterojunction was studied and rectification was observed. The maximum value of forward to reverse current ratio at room temperature was ~15 at 3.0 V. It increases to ~30 at 100oC.

scholarly journals Controllable Synthesis of Mn3O4 Nanowires and Application in the Treatment of Phenol at Room Temperature

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 461 ◽  
Author(s):  
Runlin Han ◽  
Min Chen ◽  
Xiaobing Liu ◽  
Yuhang Zhang ◽  
Yongli Xie ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Hydrothermal Reaction ◽  
X Ray Diffraction ◽  
Acid Condition ◽  
Facile Hydrothermal Method ◽  
Phenol Solution ◽  
X Ray ◽  
Before And After ◽  
Phenol Treatment

Nanosized Mn3O4 nanowires are prepared with KMnO4 and ethanol in mild conditions by facile hydrothermal method. Hydrothermal reaction temperature is optimized to get uniform nanowires. The prepared Mn3O4 nanowires exhibit high activity in the treatment of phenol at acid condition and room temperature. The 20 mg Mn3O4 nanowires can efficiently dispose of 50 mL phenol solution (0.2 g·L−1) at pH 2 and 25 °C. The nanowires before and after phenol treatment are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) and the reaction mechanism is discussed.

Thermoelasticity, cation exchange, and deprotonation in Fe-rich holmquistite: Toward a crystal-chemical model for the high-temperature behavior of orthorhombic amphiboles

2019 ◽  
Vol 104 (12) ◽  
pp. 1829-1839 ◽  
Author(s):  
Roberta Oberti ◽  
Massimo Boiocchi ◽  
Michele Zema
Keyword(s):  
Room Temperature ◽  
Isothermal Annealing ◽  
Crystal Chemical ◽  
Crystal Chemical Formula ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Elastic Parameters ◽  
Structural Units ◽  
X Ray ◽  
Before And After

Abstract The thermoelastic behavior of a crystal of Fe-rich holmquistite with crystal-chemical formula A(K0.01Na0.01)B(Li1.88Mg0.10Na0.02)C(Mg1.68Fe1.422+Mn0.022+Al1.88)TSi8.00O22W[(OH)1.97F0.03] was studied by single-crystal X-ray diffraction at temperatures up to 1023 K, where isothermal annealing in air for 160 h yielded the loss of 0.85 H apfu coupled with oxidation of M1Fe. A complex pattern of cation exchanges was deciphered by comparing structure refinements done before and after annealing. Li migration from the M4 to M3 site is responsible for nonlinearity of the c parameter around 600 K during the first annealing. Cooling of the partially deprotonated crystal to room temperature (RT) showed discontinuities in trends of the b and c parameters around 820–800 K, which cannot be ascribed to a phase transition and can be explained by a rearrangement of the structural units affecting the geometry of the M4 polyhedron. Such discontinuities have never been observed in amphiboles before and must be related to dimensional constraints deriving from the peculiar composition of this amphibole, which contains the smallest possible homovalent constituents, i.e., BLi, CAl, and TSi. The calculated thermo-elastic parameters are: Fe-rich holmquistite: αa = 1.36(2)×10–5; αb = 0.55(1)×10–5; αc = 1.5(1)×10–5 – 6.7(9)×10–9; αV = 3.5(3)×10–5 – 0.8(3)×10–8 (polynomial); 2.58(6)×10–5 (linear); partially deprotonated Fe-rich holmquistite: αa = 1.324(9)×10–5 (RT-1023 K); αb = 0.60(1)×10–5 (RT-773 K); αc = 0.68(2)×10–5 (RT-773 K); αV = 2.59(2)×10–5 (RT-773 K). Fe-rich holmquistite is much stiffer than all the previously studied orthorhombic Pnma and Pnmn amphiboles. The results of this work allow progress toward a general model that may explain how the amphibole structure responds to non-ambient conditions, and allows the release of water in diverse geological environments.

scholarly journals The Phase Diagram of Hydrogen in Ultra Thin Films

1995 ◽  
Vol 403 ◽  
Author(s):  
N. M. Jisrawi ◽  
W. Ruckman ◽  
G. Reisfeld ◽  
H. Wiesmann ◽  
F. Loeb ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Gas Sensors ◽  
Experimental Methods ◽  
Hydrogen Gas ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Number Of Layers ◽  
Before And After ◽  
Hydrogen Gas Sensors

AbstractIn this paper, we discuss changes in the phase diagram of hydrogen in both bilayer (i.e. 200–2000 Å Nb/ 100 Å Pd on glass) and multilayer configurations. In fact, it is the changes in this phase diagram, in addition to the Pd coating, that makes theses bilayer systems useful for hydrogen gas sensors. Comparison of x-ray diffraction, electrical resistivity and volumetric measurements of the films before and after hydrogen charging indicate that the phase equilibria between a correlated (high concentration) and a dilute phase of hydrogen in Nb is not sensitive to the number of layers in the films. On the other hand, the experimental methods show different behavior for 200 Å thick Nb films and thicker (>400 Å) Nb layers. Diffraction results showing unisotropic lattice expansion will also be discussed..

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

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.

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