scholarly journals Low-Temperature Synthesis and Gas Sensitivity of Perovskite-Type LaCoO3Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Lorenzo Gildo Ortiz ◽  
Héctor Guillén Bonilla ◽  
Jaime Santoyo Salazar ◽  
M. de la L. Olvera ◽  
T. V. K. Karthik ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Cobalt Nitrate ◽  
Gas Sensitivity ◽  
Tem Analysis ◽  
Operation Temperature ◽  
Transmission Electron ◽  
Colloidal Method ◽  
Perovskite Type

LaCoO3nanoparticles with perovskite-type structure were prepared by a microwave-assisted colloidal method. Lanthanum nitrate, cobalt nitrate, and ethylenediamine were used as precursors and ethyl alcohol as solvent. The thermal decomposition of the precursors leads to the formation of LaCoO3from a temperature of 500°C. The structural, morphological, and compositional properties of LaCoO3nanoparticles were studied in this work by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Pellets were manufactured in order to test the gas sensing properties of LaCoO3powders in carbon monoxide (CO) and propane (C3H8) atmospheres. Agglomerates of nanoparticles with high connectivity, forming a porous structure, were observed from SEM and TEM analysis. LaCoO3pellets presented a high sensitivity in both CO and C3H8at different concentrations and operating temperatures. As was expected, sensitivity increased with the gas concentration and operation temperature increase.

Sensing Properties of CNT hybrid MOS-based Sensors

2004 ◽  
Vol 828 ◽  
Author(s):  
Wei-Jen Liou ◽  
Tsung-Yeh Yang ◽  
Kuang-Nan Lin ◽  
Ching-Hong Yang ◽  
Hong-Ming Lin
Keyword(s):  
Electron Microscopy ◽  
Gas Adsorption ◽  
Gas Sensing ◽  
Sol Gel ◽  
Gas Sensitivity ◽  
Sensing Properties ◽  
Operation Temperature ◽  
Transmission Electron ◽  
Lower Temperature ◽  
P Type

ABSTRACTThe carbon nanotubes provide large surface that can enhance the gas adsorption properties and increase the conductivity at a lower temperature for gas sensing. The gas sensing properties of the hybrid TiO2/CNTs material are examined in this study. The sol-gel technique is used to prepare a thin layer of nano-TiO2 coated on CNTs. The structure of TiO2/CNTs hybrid materials is identified by X-ray diffraction (XRD) and Raman spectrum. The granules and surface morphology are analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrical properties of the hybrid TiO2/CNTs indicate that the operation temperature can be lowered to ambient temperature and this will enhance the gas sensitivity for detecting CO gas. The n-type or p-type behavior of hybrid TiO2/CNTs can be controlled by the coating thickness of hybrid TiO2. According to the image results, the mechanisms of the n-type and p-type behavior of hybrid TiO2/CNTs system are proposed.

scholarly journals Gas Sensing Properties of NiSb2O6 Micro- and Nanoparticles in Propane and Carbon Monoxide Atmospheres

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Verónica-M. Rodríguez-Betancourtt ◽  
Héctor Guillén Bonilla ◽  
Martín Flores Martínez ◽  
Alex Guillén Bonilla ◽  
J. P. Moran Lazaro ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Monoxide ◽  
Gas Sensing ◽  
Average Diameter ◽  
Cell Parameters ◽  
Sensing Applications ◽  
Transmission Electron ◽  
Colloidal Method ◽  
Antimony Chloride ◽  
20 Nm

Micro- and nanoparticles of NiSb2O6 were synthesized by the microwave-assisted colloidal method. Nickel nitrate, antimony chloride, ethylenediamine, and ethyl alcohol were used. The oxide was obtained at 600°C and was analyzed by X-ray diffraction (XRD) and Raman spectroscopy, showing a trirutile-type structure with cell parameters a = 4.641 Å, c = 9.223 Å, and a space group P42/mnm (136). Average crystal size was estimated at ~31.19 nm, according to the XRD-peaks. The microstructure was scrutinized by scanning electron microscopy (SEM), observing microrods measuring ~3.32 μm long and ~2.71 μm wide, and microspheres with an average diameter of ~8 μm; the size of the particles shaping the microspheres was measured in the range of ~0.22 to 1.8 μm. Transmission electron microscopy (TEM) revealed that nanoparticles were obtained with sizes in the range of 2 to 20 nm (~10.7 nm on average). Pellets made of oxide’s powders were tested in propane (C3H8) and carbon monoxide (CO) atmospheres at different concentrations and temperatures. The response of the material increased significantly as the temperature and the concentration of the test gases rose. These results show that NiSb2O6 may be a good candidate for gas sensing applications.

scholarly journals Effect of Growth Temperature and Time on Morphology and Gas Sensitivity of Cu2O/Cu Microstructures

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Ling Wu ◽  
Lun Zhang ◽  
Zhipeng Xun ◽  
Guili Yu ◽  
Liwei Shi
Keyword(s):  
Electron Microscopy ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
X Ray ◽  
Transmission Electron ◽  
Wide Range ◽  
Gas Response

A facile hydrothermal synthesis with CuSO4as the copper source was used to prepare micro/nano-Cu2O. The obtained samples have been characterized by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). With increasing the reaction temperature and time, the final products were successively Cu2O octahedron microcrystals, Cu2O/Cu composite particles, and a wide range of Cu spherical particles. The gas sensitivity of products towards ethanol and acetone gases was studied. The results showed that sensors prepared with Cu2O/Cu composites synthesized at 65°C for 15 min exhibited optimal gas sensitivity. The gas sensing mechanism and the effect of Cu in the enhanced gas response were also elaborated. The excellent gas sensitivity indicates that Cu2O/Cu composites have potential application as gas sensors.

scholarly journals An Elaborated Study of CO Sensitivities of Cu, Pt and Pd Activated SnO2 Sensors: Effect of Precipitation Agents, Dopants and Doping Methods

2017 ◽  
Author(s):  
Venkata Krishna Karthik Tangirala ◽  
Heberto Gomez-Pozos ◽  
Ventura Rodríguez-Lugo ◽  
María De La Luz Olvera
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Atmospheric Oxygen ◽  
High Sensitivity ◽  
Cost Effective ◽  
Industrial Applications ◽  
Sno2 Nanostructures ◽  
X Ray Diffraction ◽  
Enhanced Sensitivity ◽  
Transmission Electron

In this work, we report synthesis of Cu, Pt and Pd doped SnO2 powders and their comparative CO gas sensing studies. Dopants were incorporated into SnO2 nanostructures using chemical and impregnation methods by using urea and ammonia as precipitation agents. The synthesized samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM) and High resolution transmission electron microscopy (HR-TEM). The presence of dopants within the SnO2 nanostructures was evidenced from HR-TEM. Doped powders utilizing chemical methods with urea as precipitation agent presented higher sensitivities compared to the remaining, which is due to the formation of uniform and homogeneous particles resulted from the temperature assisted synthesis. The particle sizes of doped SnO2 nanostructures were in the range of 40-100 nm. An enhanced sensitivity around 1783 was achieved with Cu doped SnO2 when compared with two other dopants i.e., Pt (1200) and Pd: SnO2(502). The high sensitivity of Cu: SnO2 is due to formation of CuO and its excellent association and dissociation in the presence of CO with adsorbed atmospheric oxygen at sensor operation temperatures resulted in high conductance. Cu: SnO2 may be an alternative and cost effective sensor for industrial applications.

scholarly journals Synthesis and acetone sensing properties of ZnFe2O4/rGO gas sensors

2019 ◽  
Vol 10 ◽  
pp. 2516-2526 ◽  
Author(s):  
Kaidi Wu ◽  
Yifan Luo ◽  
Ying Li ◽  
Chao Zhang
Keyword(s):  
Electron Microscopy ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Hollow Spheres ◽  
High Sensitivity ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene

Hollow spheres of pure ZnFe2O4 and of composites of ZnFe2O4 and reduced graphene oxide (rGO) with different rGO content were prepared via a simple solvothermal method followed by a high-temperature annealing process in an inert atmosphere. The X-ray diffraction analysis confirmed that the introduction of rGO had no effect on the spinel structure of ZnFe2O4. In addition, the results of field-emission scanning electron microscopy and (high-resolution) transmission electron microscopy indicated that the synthesized samples had the structure of hollow spheres distributed uniformly onto rGO nanosheets. The diameters of the spheres were determined as about 600–1000 nm. The gas sensing test revealed that the introduction of rGO improved the performance of the sensing of acetone to low concentration, and the ZnFe2O4/rGO composite gas sensor containing 0.5 wt % of rGO exhibited a high sensitivity in sensing test using 0.8–100 ppm acetone at 200 °C. The response of the 0.5 wt % ZnFe2O4/rGO sensor to 0.8 ppm acetone was 1.50, and its response to 10 ppm acetone was 8.18, which is around 2.6 times more pronounced than the response of pure ZnFe2O4 (10 ppm, 3.20). Moreover, the sensor showed a wide linear range and good selectivity.

Study of ferroelastic behavior and microstructure in polycrystalline LaCoO3 using Transmission Electron Microscopy

2009 ◽  
Vol 3 (1) ◽  
Author(s):  
S. Kell ◽  
M. Tanase ◽  
R.F. Klie
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Defect Density ◽  
Atomic Scale ◽  
Tem Analysis ◽  
Perovskite Type Oxide ◽  
Transmission Electron ◽  
History Of ◽  
Perovskite Type

LaCoO3 is a ferroelastic perovskite-type oxide. It has been shown to undergo creep at room temperature. LaCoO3 responds to stress by changing its domain structure, resulting in formation of spontaneous strain. The microstructure of a sample of polycrystalline LaCoO3 with history of stress was investigated using Transmission Electron Microscopy (TEM). It was compared to an unstrained sample to determine what changes are produced. TEM analysis has shown an increase in defect density as well as the appearance of atomic scale ordering. The causes of the observed ordering and their relation to ferroelastic behavior are explored.

scholarly journals Synthesis, Characterization, and Hydrogen Gas Sensing of ZnO/g-C3N4 Nanocomposite

2021 ◽  
Vol 10 (1) ◽  
pp. 3
Author(s):  
Arif Ibrahim ◽  
Uzma Bano Memon ◽  
Siddartha Prakash Duttagupta ◽  
Raman R. K. Singh ◽  
Arindam Sarkar
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Hydrogen Gas ◽  
X Ray Diffraction ◽  
Material Synthesis ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Recovery Times ◽  
Response And Recovery ◽  
Gas Response

In this paper, the preparation of the ZnO/g-C3N4 nanocomposite is discussed. The synthesis of nanocomposite is performed by the direct pyrolysis of the precursor (zinc acetate hexahydrate). The material synthesis is validated by different characterization tools, such as X-ray Diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM). The SEM and TEM analysis revealed the formation of nanorods on g-C3N4 support. The gas sensing property of the ZnO/g-C3N4 was studied for various concentrations of hydrogen gas. Response and recovery times were recorded by the sensor.

Transmission Electron Microscopy of an Aluminum-Silver-Stainless Steel Solid State Bond

1985 ◽  
Vol 43 ◽  
pp. 172-173
Author(s):  
M. J. Carr ◽  
J. F. Shewbridge ◽  
T. O. Wilford
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Specimen Preparation ◽  
Dimensional Control ◽  
Tem Analysis ◽  
Metal Parts ◽  
Dissimilar Metal ◽  
Transmission Electron ◽  
Short Time

Strong solid state bonds are routinely produced between physical vapor deposited (PVD) silver coatings deposited on sputter cleaned surfaces of two dissimilar metal parts. The low temperature (200°C) and short time (10 min) used in the bonding cycle are advantageous from the standpoint of productivity and dimensional control. These conditions unfortunately produce no microstructural changes at or near the interface that are detectable by optical, SEM, or microprobe examination. Microstructural problems arising at these interfaces could therefore easily go undetected by these techniques. TEM analysis has not been previously applied to this problem because of the difficulty in specimen preparation. The purpose of this paper is to describe our technique for preparing specimens from solid state bonds and to present our initial observations of the microstructural details of such bonds.

TEM Sample Preparation Tricks for Advanced DRAMs

2015 ◽  
Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Characterization Of Materials

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

A Methodology to Reduce Ion Beam Induced Damage in TEM Specimens Prepared by FIB

2002 ◽  
Author(s):  
Chin Kai Liu ◽  
Chi Jen. Chen ◽  
Jeh Yan.Chiou ◽  
David Su
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Specimen Preparation ◽  
Tem Analysis ◽  
Sensitive Issue ◽  
Transmission Electron

Abstract Focused ion beam (FIB) has become a useful tool in the Integrated Circuit (IC) industry, It is playing an important role in Failure Analysis (FA), circuit repair and Transmission Electron Microscopy (TEM) specimen preparation. In particular, preparation of TEM samples using FIB has become popular within the last ten years [1]; the progress in this field is well documented. Given the usefulness of FIB, “Artifact” however is a very sensitive issue in TEM inspections. The ability to identify those artifacts in TEM analysis is an important as to understanding the significance of pictures In this paper, we will describe how to measure the damages introduced by FIB sample preparation and introduce a better way to prevent such kind of artifacts.

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