Preparation and Performance of ZnO Based Gas Sensors Working at Room Temperature

2013 ◽  
Vol 538 ◽  
pp. 289-292 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Electron Microscope ◽  
Transient Response ◽  
Gas Sensors ◽  
Room Temperature ◽  
X Ray ◽  
Response Characteristics ◽  
Glass Substrates ◽  
Zno Nanocrystals ◽  
Transmission Electron ◽  
And Performance

In this presentation, we present the preparation and performance of ZnO gas sensors on glass substrates. The phase and microstructures of the prepared ZnO nanocrystals were characterized with the X-ray diffractometer and transmission electron microscope. The transient response characteristics of the ZnO based sensors were recorded at room temperatures in saturated ethanol gas. It has been observed that the ZnO sensors can be operated at room temperature.

Ultrafast Response Humidity Sensor Based on Electrospun Porous BaTiO3 Nanofibers

2013 ◽  
Vol 319 ◽  
pp. 43-48 ◽  
Author(s):  
Hong Di Zhang ◽  
Chen Hao Sheng ◽  
Bin Sun ◽  
Yun Ze Long
Keyword(s):  
Electron Microscope ◽  
Recovery Time ◽  
Room Temperature ◽  
Humidity Sensor ◽  
Humidity Sensing ◽  
X Ray ◽  
Transmission Electron ◽  
Porous Microstructure ◽  
Humidity Sensing Properties ◽  
Scanning Electron

Nanocrystalline and porous barium titanate (BaTiO3) nanofibers with diameter 200-400 nm were synthesized via electrospinning and followed calcinations. The morphology and microstructure of the nanofibers were characterized using field emission scanning electron microscope, X-ray diffractometer and transmission electron microscope, respectively. And the electrical and humidity sensing properties of the nanofibers were also measured. The results reveal that the BaTiO3 nanofibers have a conductivity of about 0.3 S/cm, and show an ultrafast response time (~0.7 s) and a recovery time (~0.4 s) to humidity at room temperature. In addition, the sensing mechanism was also discussed briefly based on its nanocrystalline and porous microstructure of the electrospun material.

Electrical Resistivity Improvement by Precipitation and Strain in Al-Cu Thin Films

2010 ◽  
Vol 305-306 ◽  
pp. 33-37 ◽  
Author(s):  
S. Lallouche ◽  
M.Y. Debili
Keyword(s):  
Thin Films ◽  
Copper Content ◽  
Room Temperature ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Transmission Electron ◽  
Hall Method

This work deals with Al-Cu thin films, deposited onto glass substrates by RF (13.56MHz) magnetron sputtering, and annealed at 773K. The film thickness was approximately the same 3-4µm. They are characterized with respect to microstructure, grain size, microstrain, dislocation density and resistivity versus copper content. Al (Cu) deposits containing 1.8, 7.21, 86.17 and 92.5at%Cu have been investigated. The use of X-ray diffraction analysis and transmission electron microscopy lead to the characterization of different structural features of films deposited at room temperature (< 400K) and after annealing (773K). The resistivity of the films was measured using the four-point probe method. The microstrain profile obtained from XRD thanks to the Williamson-Hall method shows an increase with increasing copper content.

Doped Tin Oxide Nanometric Films for Environment Monitoring

2005 ◽  
Vol 498-499 ◽  
pp. 636-641 ◽  
Author(s):  
P. Hidalgo Falla ◽  
H.E.M. Peres ◽  
Douglas Gouvêa ◽  
F.J. Ramirez-Fernandez
Keyword(s):  
Gas Sensors ◽  
Room Temperature ◽  
Tin Dioxide ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Relative Resistance ◽  
X Ray ◽  
Grain Sizes ◽  
Transmission Electron ◽  
Resistance Variation

In this work tin dioxide (SnO2) doped with nickel is studied with the aim of develop integrated gas sensors for some important pollution gases into environment, principally sulphur dioxide (SO2). SnO2 powders doped with Nickel were prepared by Pechini`s method [1] and characterized morphologically by X-Ray diffraction, measurement of specific surface area (SBET) and transmission electron microscopy (TEM), which revealed grain sizes around 5 to 10 nm. Gas sensors were fabricated by spin-coating deposition of Ni doped SnO2 films over alumina substrate with gold contacts. Electrical resistance of such device is characterized, at room temperature, as function of SO2 concentration into environment, showing a sensitivity around 0.0058 ppm-1 for relative resistance variation, with good linearity for SO2 concentrations up to 30 ppm. Also, FTIR analysis shows the desorption of SO2 from SnO2 surface, after cleaning into fresh air.

scholarly journals Gas Phase Growth of Wurtzite ZnS Nanobelts on a Large Scale

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Jing Wang ◽  
Yang Jiao ◽  
Yang Liu ◽  
Zhenglin Zhang ◽  
Fengyu Qu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Large Scale ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Deep Level ◽  
Green Emission ◽  
X Ray Diffraction ◽  
Phase Growth ◽  
X Ray ◽  
Transmission Electron

We showed large-scale synthesis of ZnS nanobelts by simply thermal evaporation of ZnS powder in the presence of Au catalysts at 1020°C. Scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD) analyses demonstrated that the as-obtained ZnS nanobelts possess hexagonal wurtzite structures. The nanobelts have lengths ranging from tens to hundreds of micrometers, thicknesses of tens of nanometers, and widths ranging from hundreds of nanometers to the order of micrometers. The growth process was proposed on the basis of known vapor-liquid-solid (VLS) mechanism. Room temperature photoluminescence measurements showed that the as-synthesized ZnS nanostructures had a strong green emission bands at a wavelength of 427 nm, which can be attributed to deep-level emissions induced by defects or impurities.

X-ray Determination and Finite-Element Modeling of Stress in Passivated Al-0.5%Cu Lines During Thermal Cycling.

1993 ◽  
Vol 309 ◽  
Author(s):  
Paul R. Besser ◽  
Anne Sauter Mack ◽  
David Fraser ◽  
John C. Bravman
Keyword(s):  
Finite Element ◽  
Electron Microscope ◽  
Strain State ◽  
Room Temperature ◽  
Scanning Transmission Electron Microscope ◽  
X Rays ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Voltage Scanning

AbstractWe have measured the principal strain state of AI-0.5%Cu lines passivated with silicon nitride directly and used it to calculate the stress state. The stress was determined as the lines were thermally cycled from room temperature to 450°C. The general stress-temperature behavior shows good fundamental agreement with that calculated using finite-element methods, although the magnitude of the stresses measured with x-rays is less than that predicted by modeling due to stressinduced voiding in the lines. This is shown with a high voltage scanning transmission electron microscope (STEM) operated in the backscattering mode.

Epitaxial growth of Co/Cu[100] and [111] superlattices via rf sputtering on sapphire (1120)-substrates

1994 ◽  
Vol 9 (3) ◽  
pp. 570-581 ◽  
Author(s):  
Ch. Morawe ◽  
A. Abromeit ◽  
N. Metoki ◽  
P. Sonntag ◽  
H. Zabel
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Rf Sputtering ◽  
Growth Direction ◽  
Substrate Orientation ◽  
Careful Choice ◽  
X Ray ◽  
Transmission Electron ◽  
Average Lattice

Co/Cu superlattices with total thicknesses ranging from 10 nm to 60 nm and with periodicities of 1.6–8.5 nm were sputtered on single-crystalline sapphire (1120)-substrates. Sputtering with low rates at room temperature yields samples of high epitaxial and crystalline quality. By careful choice of the sputtering parameters, either the fee [100] or the fcc [111] orientation can be selected as growth direction on one and the same substrate orientation. The preference for a particular film orientation appears to be kinetically driven. In all cases, the average lattice spacings d and the appearance of satellite reflections in x-ray Bragg-scans point to coherent growth up to thicknesses of 30 nm. X-ray small angle reflectivity measurements reveal clear oscillations and satellites indicative for smooth interfaces. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations supplement the characterization of the films.

Synthesis and Photoluminescence Properties of Sm3+-Doped Ca10(PO4)6(OH)2 Nanowire

2011 ◽  
Vol 391-392 ◽  
pp. 1123-1127
Author(s):  
Qi Xiao ◽  
Lan Gao
Keyword(s):  
Electron Microscope ◽  
Emission Intensity ◽  
Room Temperature ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Transmission Electron ◽  
Transmission Electron Microscope Analysis ◽  
Electron Microscope Analysis

The Sm3+-doped Ca10(PO4)6(OH)2 nanowires are synthesized by hydrothermal method. X-ray diffraction confirmed that the nanowires are made of the hexagonal Ca10(PO4)6(OH)2. Scanning electron microscope and transmission electron microscope analysis show that the lengths of the nanowires are approximately 5μm, and their diameters are around 100 nm, and the aspect (length/diameter) ratio is about 50. The room temperature photoluminescence (PL) spectra of Sm3+-doped Ca10(PO4)6(OH)2 nanowires doped with different Sm3+ concentration under 405 nm excitation has been investigated. It is found that there are three main sharp emissions peaks at near 569, 604, and 649 nm. The three emissions are due to the f-f forbidden transitions of the 4f electrons of Sm3+, corresponding to 4G5/2→6H5/2 (569 nm), 6H7/2(604 nm), and 6H9/2(649 nm), respectively. In addition, concentration quenching is also observed. It is found that the Sm3+4G5/2→6H7/2(604 nm) emission intensity of Sm3+-doped Ca10(PO4)6(OH)2 nanowires significantly increases with the increase of Sm3+ concentration, and shows a maximum when Sm3+ doping content is 0.5%. If Sm3+ concentration continues to increase, namely more than 0.5%, the Sm3+4G5/2→6H7/2 emission intensity decreases.

Structural and Ferromagnetic Properties SnO2/TiO2 Nanotubes Obtained by Electrospinning

NANO ◽  
2017 ◽  
Vol 12 (10) ◽  
pp. 1750127 ◽  
Author(s):  
Jian-Guo Zhao ◽  
Yan-Hong Gu ◽  
Hong Jia ◽  
Zhuan Hu ◽  
Shuqian Qiao ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electrospinning Method ◽  
Inner Diameter ◽  
Superconducting Quantum Interferometer

SnO2/TiO2 (Sn/Ti [Formula: see text]/1) nanotubes were prepared by the electrospinning method. The morphology was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the inner diameter of prepared materials was about 100[Formula: see text]nm and the wall thickness was about 10[Formula: see text]nm. The results of X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM) showed that SnO2/TiO2 nanotubes had a mixed phase of SnO2 rutile and TiO2 anatase structures and no impurity phases. The magnetic properties of the SnO2/TiO2 nanotubes were characterized by a superconducting quantum interferometer (SQUID). The results indicated that the samples exhibited room temperature ferromagnetism which may be attributed to the interface between TiO2 and SnO2 phases.

Synthesis of α-MoO3 Microspheres Assembled by Nanorods in Room Temperature Ionic Liquids

2011 ◽  
Vol 236-238 ◽  
pp. 2008-2011
Author(s):  
Liu Zhi ◽  
Yan Song ◽  
Li Ping Deng ◽  
Xing Hai Liu
Keyword(s):  
Ionic Liquids ◽  
Electron Microscope ◽  
Room Temperature ◽  
Influence Factor ◽  
Room Temperature Ionic Liquids ◽  
Fourier Transform Spectrometer ◽  
Heating Method ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

α-MoO3microspheres assembled by nanorods were synthesized in room temperature ionic liquids (bmimBF4: 1-butyl-3-methylimidazolium tetrafluoroborate) by microwaves heating method. The microstructure and morphology of the products were characterized by the techniques of X-ray powder diffraction (XRD), Fourier-transform spectrometer (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM). The influence factor such as the amount of ammonium heptamolybdenum tetrahydrate in ionic liquids was investigated in detail. The possible reaction mechanism was also discussed. It was demonstrated that the ionic liquid could act as template agent for the formation of α-MoO3microspheres. The present synthesis route is very simple and fast, and could be extended to the fabrication of other nanomaterials in ionic liquids.

Sign in / Sign up

Export Citation Format

Share Document