Decoration of Gold Nanoparticles on TiO2 Thin Films for Enhanced Response of Ethanol Gas Sensors

2014 ◽  
Vol 979 ◽  
pp. 251-254 ◽  
Author(s):  
Benjarong Samransuksamer ◽  
Mati Horprathum ◽  
Pitak Eiamchai ◽  
Viyapol Patthanasettakul ◽  
Anurat Wisitsoraat ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Sensors ◽  
Au Nanoparticles ◽  
Operating Temperature ◽  
Element Composition ◽  
Dc Magnetron Sputtering ◽  
Au Nps ◽  
X Ray ◽  
Gas Concentration ◽  
Average Size

This work investigated the decoration of the gold (Au) nanoparticles (NPs) on the TiO2 thin films for the applications in ethanol gas sensors. The Au-decorated TiO2 thin films (Au-TiO2) were prepared by the DC magnetron sputtering on the silicon (100) wafers and alumina substrates, interdigitated with Au electrodes. The distribution and size of Au nanoparticles were controlled by varying the sputtering time. Morphologies and element composition of the Au-TiO2 films were examined by field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX) respectively. The FE-SEM micrographs when the sputtering time was increased, the average size of the Au NPs was also increased. On the other hand, the distribution of the Au NPs was decreased. The change in size and distribution of the Au NPs consequently improved the response of ethanol gas sensors. The prepared Au-TiO2 was tested, in comparison with TiO2 reference films, as the ethanol sensors at 250-350oC in 50-1,000 ppm gas concentration. The results showed that the TiO2 thin film with Au-decorated at 6 sec sputtering time yielded the highest response of 514 at 350oC operating temperature and 1,000 ppm gas concentration.

Thin film combustible gas sensors based on Zinc Oxide

2001 ◽  
Vol 666 ◽  
Author(s):  
Patrícia Nunes ◽  
Elvira Fortunato
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Zinc Oxide ◽  
Gas Sensors ◽  
Operating Temperature ◽  
Zno Thin Films ◽  
Gas Concentration ◽  
High Electrical Resistivity ◽  
Combustible Gas ◽  
Sensitivity Tests

ABSTRACTSensitivity tests to reductive gases such as methane, hydrogen and ethane were performed on zinc oxide (ZnO) thin films. The highest value of sensitivity was obtained for the film with a high electrical resistivity and a low thickness. The variation of the operating temperature of the film leads to a significant change in the sensitivity of the sensor with an ideal operating temperature dependence of the gas used. The sensitivity of the ZnO thin films changes linear with the increase of the gas concentration. However these films seem to be more appropriated for the detection of hydrogen following by methane and than for ethane since the value of sensitivity obtained are higher and its variation with the gas concentration more pronounced.

Synthesis of Au Nanoparticles Functionalized 1D α-MoO3 Nanobelts and Their Gas Sensing Properties

NANO ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. 1850115 ◽  
Author(s):  
Liwei Wang ◽  
Shaopeng Wang ◽  
Hao Fu ◽  
Yinghui Wang ◽  
Kefu Yu
Keyword(s):  
Electron Microscope ◽  
Au Nanoparticles ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Molecular Probe ◽  
Optimal Operating ◽  
Au Nps ◽  
X Ray ◽  
Sensing Properties ◽  
Optimal Operating Temperature

A novel sensor material of Au nanoparticles (NPs) functionalized 1D [Formula: see text]-MoO3 nanobelts (NBs) was fabricated by a facile lysine-assisted approach. The obtained Au/[Formula: see text]-MoO3 product was characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray (EDX), and X-ray photoelectron spectra (XPS). Then, in order to investigate the gas sensing performances of our samples, a comparative gas sensing study was carried out on both the [Formula: see text]-MoO3 NBs before and after Au NPs decoration by using ethanol vapor as the molecular probe. The results turned out that, after the functionalization of Au NPs, the sensor exhibited improved gas-sensing characteristics than the pure [Formula: see text]-MoO3, such as response and recovery time, optimal operating temperature (OT) and excellent selectivity. Take for example 200[Formula: see text]ppm of ethanol, the response/recovery times were 34[Formula: see text]s/43[Formula: see text]s and 5.7[Formula: see text]s/10.5[Formula: see text]s, respectively, while the optimal operating temperature (OT) was lower to 200[Formula: see text]C rather than 250[Formula: see text]C. Besides, the functionalized sensor showed a higher response to ethanol at 200[Formula: see text]C, and response was 1.6 times higher than the pure MoO3. The mechanism of such improved sensing properties was interpreted, which might be attributed to the spillover effect of Au NPs and the electronic metal-support interaction.

CuOX Films for NO2 Detection: Microstructural Characterization

2013 ◽  
Vol 481 ◽  
pp. 133-136 ◽  
Author(s):  
T.N. Myasoedova ◽  
G.E. Yalovega ◽  
N.K. Plugotarenko ◽  
M. Brzhezinskaya ◽  
V.V. Petrov ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Secondary Electron ◽  
Operating Temperature ◽  
Sol Gel ◽  
Microstructural Characterization ◽  
Temperature Treatment ◽  
Copper Oxides ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

Copper oxides films as promising materials for gas sensors applications were studied. Copper oxide films were deposited onto Si/SiO2substrates using a citrate sol-gel method with the subsequent temperature treatment at 150-5000C. These films were characterized by means of secondary electron microscopy (SEM) and X-ray-absorption near-edge structure (XANES) spectroscopy. The prepared films were utilized in NO2sensors. The dependences of the NO2response on the operating temperature and NO2concentration (10-200 ppm) were investigated. The maximum NO2response was achieved for the film annealed at 2500C.

Transparent Conductive Cu-In-O Thin Films Deposited by Reactive DC Magnetron Sputtering with Different Targets

2011 ◽  
Vol 239-242 ◽  
pp. 2752-2755
Author(s):  
Fan Ye ◽  
Xing Min Cai ◽  
Fu Ping Dai ◽  
Dong Ping Zhang ◽  
Ping Fan ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Optical Band Gap ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Flow Rates ◽  
X Ray ◽  
Equal Distance ◽  
Transmittance Curve

Transparent conductive Cu-In-O thin films were deposited by reactive DC magnetron sputtering. Two types of targets were used. The first was In target covered with a fan-shaped Cu plate of the same radius and the second was Cu target on which six In grains of 1.5mm was placed with equal distance between each other. The samples were characterized with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV/VIS spectrophotometer, four-probe measurement etc. SEM shows that the surfaces of all the samples are very smooth. EDX shows that the samples contain Cu, In as well as O, and different targets result in different atomic ratios of Cu to In. A diffraction peak related to rhombohedra-centered In2O3(012) is observed in the XRD spectra of all the samples. For both the two targets, the transmittance decreases with the increase of O2flow rates. The direct optical band gap of all the samples is also estimated according to the transmittance curve. For both the two targets, different O2flow rates result in different sheet resistances and conductivities. The target of Cu on In shows more controllability in the composition and properties of Cu-In-O films.

scholarly journals Study of properties of electrical conductivity of Tin dioxide thin films treated with Xenon impulse radiation used as Gas sensors

2009 ◽  
Vol 6 (4) ◽  
pp. 693-697
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Short Duration ◽  
Gas Sensors ◽  
Tin Dioxide ◽  
Experimental Result ◽  
Gas Sensitivity ◽  
Gas Concentration ◽  
Similar Character

During of Experimental result of this work , we found that the change of electrical conductivity proprieties of tin dioxide with the change of gas concentration at temperatures 260oC and 360oC after treatment by photons rays have similar character after treatment isothermally. We found that intensive short duration impulse annealing during the fractions of a second leads to crystallization of the films and to the high values of its gas sensitivity.

The Use of BaF2 Buffer Layers for the Sputter-Deposition of Ticabacuo Thin-Film Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
K.M. Hubbard ◽  
P.N. Arendt ◽  
D.R. Brown ◽  
D.W. Cooke ◽  
N.E. Elliott ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Sputter Deposition ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
X Ray ◽  
Film Substrate ◽  
Ion Backscattering ◽  
Scanning Electron

AbstractThin films of the Tl‐based superconductors often have relatively poor properties because of film/substrate interdiffusion which occurs during the anneal. We have therefore investigated the use of BaF2 as a diffusion barrier. TICaBaCuO thin films were deposited by dc magnetron sputtering onto MgO <100> substrates, both with and without an evaporation‐deposited BaF2 buffer layer, and post‐annealed in a Tl over‐pressure. Electrical properties of the films were determined by four‐point probe analysis, and compositions were measured by ion‐backscattering spectroscopy. Structural analysis was performed by X‐ray diffraction and scanning electron microscopy. The BaF2 buffer layers were found to significantly improve the properties of the TICaBaCuO thin films.

scholarly journals Enhanced Photocatalytic Performance and Mechanism of Au@CaTiO3 Composites with Au Nanoparticles Assembled on CaTiO3 Nanocuboids

Micromachines ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 254 ◽  
Author(s):  
Yuxiang Yan ◽  
Hua Yang ◽  
Zao Yi ◽  
Ruishan Li ◽  
Xiangxian Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Photocatalytic Performance ◽  
Au Nanoparticles ◽  
Diffuse Reflectance Spectroscopy ◽  
Localized Surface Plasmon ◽  
Hydrothermal Route ◽  
Electron Hole ◽  
Photoexcited Electron ◽  
Au Nps ◽  
X Ray

Using P25 as the titanium source and based on a hydrothermal route, we have synthesized CaTiO3 nanocuboids (NCs) with the width of 0.3–0.5 μm and length of 0.8–1.1 μm, and systematically investigated their growth process. Au nanoparticles (NPs) of 3–7 nm in size were assembled on the surface of CaTiO3 NCs via a photocatalytic reduction method to achieve excellent Au@CaTiO3 composite photocatalysts. Various techniques were used to characterize the as-prepared samples, including X-ray powder diffraction (XRD), scanning/transmission electron microscopy (SEM/TEM), diffuse reflectance spectroscopy (UV-vis DRS), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Rhodamine B (RhB) in aqueous solution was chosen as the model pollutant to assess the photocatalytic performance of the samples separately under simulated-sunlight, ultraviolet (UV) and visible-light irradiation. Under irradiation of all kinds of light sources, the Au@CaTiO3 composites, particularly the 4.3%Au@CaTiO3 composite, exhibit greatly enhanced photocatalytic performance when compared with bare CaTiO3 NCs. The main roles of Au NPs in the enhanced photocatalytic mechanism of the Au@CaTiO3 composites manifest in the following aspects: (1) Au NPs act as excellent electron sinks to capture the photoexcited electrons in CaTiO3, thus leading to an efficient separation of photoexcited electron/hole pairs in CaTiO3; (2) the electromagnetic field caused by localized surface plasmon resonance (LSPR) of Au NPs could facilitate the generation and separation of electron/hole pairs in CaTiO3; and (3) the LSPR-induced electrons in Au NPs could take part in the photocatalytic reactions.

EPITAXIALLY GROWN YBCO THIN FILMS ON LOW LOSS LaAlO3 SUBSTRATE

1990 ◽  
Vol 04 (05) ◽  
pp. 369-373 ◽  
Author(s):  
Y. Z. ZHANG ◽  
L. LI ◽  
Y. Y. ZHAO ◽  
B. R. ZHAO ◽  
Y. G. WANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Low Loss ◽  
X Ray ◽  
Ybco Thin Films ◽  
Zero Resistance ◽  
Scanning Electron

A planar dc magnetron sputtering device was used to prepare high T c and high J c YBCO thin films. Both single crystal and polycrystal thin films were successfully grown on (100) oriented LaAlO 3 substrates. Zero resistance temperature T c0 = 92.3 K and critical current density J c (0) = 3.82 × 106 A/cm 2 at 77 K was obtained. The films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Formation and Characteristics of Thin Films of ZrO2-8 mol % Y2O3 Solid Electrolytes

2004 ◽  
Vol 97-98 ◽  
pp. 153-158 ◽  
Author(s):  
Darius Milčius ◽  
L.L. Pranevičius ◽  
V. Širvinskaitė ◽  
T. Šalkus ◽  
A. Kežionis ◽  
...  
Keyword(s):  
Thin Films ◽  
Solid Electrolytes ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Cubic Symmetry ◽  
X Ray ◽  
Pulsed Dc ◽  
Pulsed Dc Magnetron Sputtering ◽  
Diffraction Patterns

Thin films of ZrO2-8mol%Y2O3 have been deposed by pulsed DC magnetron sputtering method. The substrates of Ni-cermet and alloy-600 for the films were used. The results of the investigation of the X-ray diffraction patterns and SEM showed that the films are nanocrystalline and belong to cubic symmetry. The relaxation process is related to the ion transport in thin films. The results of the investigation of the temperature dependencies of thin films ionic conductivity (σ) showed that the dependence σ(T) is caused by the temperature dependence of oxygen vacancy mobility, while the number of charge carriers remains constant with temperature.

scholarly journals Highly Sensitive InOxOzone Sensing Films on Flexible Substrates

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
G. Kiriakidis ◽  
K. Moschovis ◽  
I. Kortidis ◽  
R. Skarvelakis
Keyword(s):  
Thin Films ◽  
Gas Sensors ◽  
Air Conditioning ◽  
Room Temperature ◽  
Growth Conditions ◽  
Flexible Substrates ◽  
Dc Magnetron Sputtering ◽  
Surface Cracking ◽  
Highly Sensitive ◽  
Extended Surface

InOxthin films with a thickness of the order of 100 nm were grown by dc magnetron sputtering on glass, Si and flexible (PET) substrates. The electrical conductivity ofInOxthin films exhibited a change of two orders of magnitude during photoreduction with ultraviolet light and subsequent oxidation in ozone concentrations from 2370 to 15 ppb, at room temperature. Optical transparency of over 85% for all substrates was maintained. Film structural and ozone sensing properties were analyzed. Surface morphology investigations carried out by SEM for films on PET substrates showed extended surface cracking for bending angles beyond40∘. Optimization of growth conditions has led to films with extremely low detection levels for ozone down to 15 ppb at room temperature, demonstrating the wide prospective of utilizing these metal oxides as gas sensors on flexible substrates for a variety of automotive and air-conditioning applications.

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