scholarly journals Fabrication of ZnO/CNTs for Application in CO2 Sensor at Room Temperature

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3087
Author(s):  
Rana Saad ◽  
Ahmed Gamal ◽  
Mohamed Zayed ◽  
Ashour M. Ahmed ◽  
Mohamed Shaban ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Chemical Vapor ◽  
Xrd Analysis ◽  
Chemical Vapor Deposition Method ◽  
Spray Pyrolysis Method ◽  
X Ray Diffraction ◽  
Co2 Gas ◽  
X Ray ◽  
Co2 Sensor ◽  
Higher Sensitivity

Thin films of ZnO and ZnO/carbon nanotubes (CNTs) are prepared and used as CO2 gas sensors. The spray pyrolysis method was used to prepare both ZnO and ZnO/CNTs films, with CNTs first prepared using the chemical vapor deposition method (CVD). The chemical structure and optical analyses for all the prepared nanomaterials were performed using X-ray diffraction (XRD), Fourier transformer infrared spectroscopy (FTIR), and UV/Vis spectrophotometer devices, respectively. According to the XRD analysis, the crystal sizes of ZnO and ZnO/CNTs were approximately 50.4 and 65.2 nm, respectively. CNTs have average inner and outer diameters of about 3 and 13 nm respectively, according to the transmitted electron microscope (TEM), and a wall thickness of about 5 nm. The detection of CO2 is accomplished by passing varying rates of the gas from 30 to 150 sccm over the prepared thin-film electrodes. At 150 sccm, the sensitivities of ZnO and ZnO/CNTs sensors are 6.8% and 22.4%, respectively. The ZnO/CNTs sensor has a very stable sensitivity to CO2 gas for 21 days. Moreover, this sensor has a high selectivity to CO2 in comparison with other gases, in which the ZnO/CNTs sensor has a higher sensitivity to CO2 compared to H2 and C2H2.

scholarly journals The changing of silicon suboxide film thickness as a result of high temperature annealing

2019 ◽  
Vol 196 ◽  
pp. 00053
Author(s):  
Alexandr Zamchiy ◽  
Evgeniy Baranov
Keyword(s):  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Plasma Chemical ◽  
Flow Rates ◽  
X Ray ◽  
Plasma Chemical Vapor Deposition ◽  
Silicon Suboxide ◽  
Deposited Films ◽  
Electron Beam Plasma

The a-SiOx:H thin films were deposited by the gas-jet electron beam plasma chemical vapor deposition method with different stoichiometry (x=0.15-1.0) for different SiH4 flow rates. The concentration of hydrogen in the films increases with the growth rate in ranges from 1.5 to 4.8 at.%. Further annealing leads to the effusion of hydrogen from the structure of the material and the compression of the structure, which leads to a reduction in the thickness for all films. X-ray diffraction measurements showed that the as-deposited films crystallized to form nc-Si about 4-8 nm in size after annealing at 1000°C.

scholarly journals Fabrication of CaO Insulator Coatings by MOCVD for Application in Fusion Reactor Blankets

2001 ◽  
Vol 697 ◽  
Author(s):  
Z. Zeng ◽  
K. Natesan
Keyword(s):  
Chemical Vapor ◽  
Liquid Lithium ◽  
Chemical Vapor Deposition Method ◽  
Fusion Reactors ◽  
X Ray Diffraction ◽  
Electrical Insulator ◽  
X Ray ◽  
Coating Composition ◽  
Microscopy Images ◽  
Lithium Blanket

AbstractThe liquid lithium blanket for fusion reactors requires an electrically insulating coating on the duct to minimize the magnetohydrodynamic pressure drop that occurs during the flow of liquid metal in a magnetic field. Calcium oxide (CaO) is a good candidate for the coating material because it is an excellent electrical insulator and it is stable in a liquid lithium environment. In this paper, details are presented on metalorganic chemical-vapor deposition method that was used to fabricate the CaO coating. Composition and phase analyses of the coating were performed by energy dispersive X-ray analysis and X-ray diffraction. Scanning electron microscopy images show that the coating did not crack after several thermal cycles from room temperature to 715°C. The resistance of the coating is high enough for an insulating coating on the liquid lithium blanket of fusion reactors.

Crystalline Orientation of PbTiO3 Nanorods Grown by MOCVD Using ZnO Nanorods as a Template

2011 ◽  
Vol 1292 ◽  
Author(s):  
Hironori Fujisawa ◽  
Masaru Shimizu ◽  
Ryohei Kuri ◽  
Seiji Nakashima ◽  
Yasutoshi Kotaka ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Zno Nanorods ◽  
Chemical Vapor ◽  
Piezoresponse Force Microscopy ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Crystalline Orientation ◽  
X Ray ◽  
Force Microscopy

ABSTRACTPbTiO3-covered ZnO nanorods were grown on Al2O3$\left({11\bar 20} \right)$ by metalorganic chemical vapor deposition (MOCVD), and their crystalline orientation was investigated by x-ray diffraction (XRD). Structural analysis by scanning electron microscopy and XRD revealed that the hexagonal ZnO nanorods had $\left\{ {10\bar 10} \right\}$-side facets. XRD analysis of PbTiO3 thin films on ZnO$\left({10\bar 10} \right)$/Al2O3$\left({10\bar 10} \right)$revealed that PbTiO3 was epitaxially grown on ZnO$\left({10\bar 10} \right)$, showing 6 variants of crystallites with the c-axis tilted either 27o or 69o from the surface normal to the ZnO$\left({10\bar 10} \right)$ plane. Effective piezoelectric coefficients calculated for the 27o and 69o-crystallites using piezoresponse force microscopy confirm that deformation of nanorods and nanotubes contributed to the large electrically-induced strain along the radial direction.

Strain Evaluation of GaAs Layers Grown on Ultrahigh-Pressure-Annealed Strain-Free GaAs-On-Si Structures

1997 ◽  
Vol 486 ◽  
Author(s):  
Takehito Jimbo ◽  
Hiroshi Ishiwara
Keyword(s):  
Chemical Vapor ◽  
Xrd Analysis ◽  
Gaas Layer ◽  
Ultrahigh Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Gaas On Si ◽  
Gaas Films ◽  
Regeneration Effect

AbstractIn order to form strain-free GaAs films on Si substrates, GaAs-on-Si structures have been formed by molecular beam epitaxy (MBE) or metalorganic chemical vapor deposition (MOCVD) and subsequently annealed under ultrahigh pressure at 2 GPa. The samples were then reannealed at atmospheric pressure in order to investigate the regeneration effect of strain in the GaAs films. It was found from X-ray diffraction (XRD) analysis and photoluminescence (PL) measurement that in the reannealed samples the strain near the surface of GaAs film was smaller than that near the interface with Si. Finally, additional GaAs layers were grown using MBE on both as-grown and strain-free GaAs-on-Si structures and it was found that the residual strain in the GaAs layer on strain-free GaAs-on-Si structure was smaller than in the as-grown case.

scholarly journals Sustainable Functionalization of PAN to Improve Tinctorial Capacity

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3665
Author(s):  
Vasilica Popescu ◽  
Ingrid Ioana Buciscanu ◽  
Melinda Pruneanu ◽  
Stelian Sergiu Maier ◽  
Angela Danila ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Xrd Analysis ◽  
Hypervalent Iodine ◽  
X Ray Diffraction ◽  
X Ray ◽  
Yellow Orange ◽  
The Fourier Transform ◽  
Scanning Electron ◽  
Pan Fibers

This study may open a new way to obtain the coloration of a polymer during functionalization. Two polyacrylonitrile (PAN) polymers in the form of textile fibers (Melana and Dralon L) were subjected to functionalization treatments in order to improve the dyeing capacity. The functionalizations determined by an organo-hypervalent iodine reagent developed in situ led to fiber coloration without using dyes. KIO3 was formed in situ from the interaction of aqueous solutions of 3–9% KOH with 3–9% I2, at 120 °C. The yellow-orange coloration appeared as a result of the transformations in the chemical structure of each functionalized polymer, with the formation of iodinehydrin groups. The degree of functionalization directly influenced the obtained color. The results of the Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Map and Temogravimetric Analysis (TG) plus Differential Thermal (DTA) analyses indicated the presence of new functional groups, such as iodine-oxime. The X-ray diffraction (XRD) analysis confirmed the change of the crystalline/amorphous ratio in favor of the former. The new groups introduced by functionalization make it possible to dye with classes of dyes specific to these groups, but not specific to PAN fibers, thus improving their dyeing capacity.

Growth and Photoluminescence of β-SiC Nanowires on Porous Silicon Array

2013 ◽  
Vol 662 ◽  
pp. 11-15
Author(s):  
Hai Yan Wang ◽  
Li Ping Kang ◽  
Yong Qiang Wang ◽  
Zi Jiong Li
Keyword(s):  
Electron Microscopy ◽  
Porous Silicon ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Fluorescent Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sic Nanowires ◽  
Quantum Confinement Effects ◽  
Transmission Electron

Nonaligned and curly β-SiC nanowires (nw-SiC) were grown on porous silicon array (PSA) by a chemical vapor deposition method with nickel as the catalyst. The morphology, structure and the composition of the nw-SiC/PSA and the SiC-SiO2core-shell fibers which is the semi-product were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Based on the experimental results a possible growth mechanism of nw-SiC was explained. Two broad photoluminescence peaks located around ~409 and ~494 nm were observed in nw-SiC/PSA in the PL measurement when utilizing 300 nm ultraviolet fluorescent light excited at room temperature. The excellent luminescent performances are ascribed to the quantum confinement effects in nw-SiC. The optical merits of nw-SiC/PSA made it a promising material in the fields of ultraviolet-blue emitting devices.

The deposition of α–Fe2O3 by aerosol chemical vapor deposition

1995 ◽  
Vol 10 (5) ◽  
pp. 1307-1311 ◽  
Author(s):  
A. Martínez ◽  
J. Peña ◽  
M. Labeau ◽  
J.M. González-Calbet ◽  
M. Vallet-Regí
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Magnetic Measurements ◽  
Chemical Vapor ◽  
Spray Pyrolysis Method ◽  
X Ray Diffraction ◽  
Good Adherence ◽  
X Ray ◽  
Pyrolysis Method ◽  
Scanning Electron

α-Fe2O3 thin films have been deposited on Si(111) substrates at high temperatures (600–800 °C) by the spray pyrolysis method. Four different iron(III) β-diketonates have been used as precursors in order to obtain polycrystalline films of good adherence, which have been characterized by x-ray diffraction, scanning electron microscopy, and magnetic measurements.

Chemical Vapor Deposition (CVD) of Parylene Films using Liquid Source Delivery

1998 ◽  
Vol 555 ◽  
Author(s):  
Chongying Xu ◽  
Thomas H. Baum
Keyword(s):  
Thermogravimetric Analysis ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Xrd Analysis ◽  
Polymeric Films ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Source ◽  
Pyrolysis Unit

AbstractParylene-N films were formed on silicon substrates at a substrate temperature of −20 °C and pressures from 4 - 7 torr via liquid source precursor delivery. [2.2 ] Paracyclophane, the precursor of parylene-N, was dissolved in an organic solvent and delivered into a vaporizer / pyrolysis unit. The solution was vaporized at ∼ 200 °C and its vapor was cracked at ∼ 700 °C to generate the reactive morromeric species. Films were grown by condensation and polymerization, and analyzed by infrared (FTIR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) analysis. These analyses indicated the formation of parylene-N films without detectable solvent contamination or incorporation into the polymeric films.

Preparation of Titanium Coating on Alumina Foam by Chemical Vapor Deposition

2014 ◽  
Vol 804 ◽  
pp. 195-198 ◽  
Author(s):  
Ke Zheng Sang ◽  
Lin He ◽  
Xin Gang Hui ◽  
Yong Zhang ◽  
Jian Feng Yang
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Energy Dispersive Spectrometer ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Titanium Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Coverage ◽  
Alumina Foam

A metal titanium coating was prepared in alumina foam by chemical vapor deposition method. The phase composition of the coating was analyzed by X-ray diffraction (XRD). The coverage of the coating on the alumina foam was analyzed by both optical and scanning electron microscope (SEM) with energy dispersive spectrometer (EDS). The results showed that the obtained titanium coating had a high purity, and showed a good coverage and uniform distribution on the skeleton surface of the foam. The skeleton surface became smooth due to coverage of the tiny holes and cracks by the coating.

scholarly journals Structural and Thermal Properties of Starch Plasticized with Glycerol/Urea Mixture

2021 ◽  
Author(s):  
Magdalena Paluch ◽  
Justyna Ostrowska ◽  
Piotr Tyński ◽  
Waldemar Sadurski ◽  
Marcin Konkol
Keyword(s):  
Thermal Properties ◽  
Chemical Structure ◽  
Gel Permeation Chromatography ◽  
Xrd Analysis ◽  
Thermoplastic Starch ◽  
X Ray Diffraction ◽  
Screw Extruder ◽  
X Ray ◽  
Twin Screw ◽  
Starch Retrogradation

AbstractThe paper presents the results of research on the influence of used plasticizing system on the structural and thermal properties of thermoplastic starch (TPS). The thermoplastic starch granulate was obtained by extrusion of native starch in the presence of a plasticizing system using a twin-screw extruder. Glycerol and urea were used as plasticizers in various proportions. In order to evaluate the effectiveness of the starch plasticization process, changes in its chemical structure were analyzed by infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and X-ray diffraction (XRD). TPS thermal stability was determined by thermogravimetric analysis (TGA). An improvement in the efficiency of the plasticization process has been found for a urea-containing plasticizing system compared to the composition of starch plasticized only with glycerol. In addition, the XRD analysis confirms the beneficial effect of urea on the inhibition of starch retrogradation process.

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