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1.
GANESH E PATIL D D KAJALE D N CHAVAN N K PAWAR P T AHIRE S D SHINDE V B GAIKWAD G H JAIN 《Bulletin of Materials Science》2011,34(1):1-9
In this work, SnO2 thin films were deposited onto alumina substrates at 350°C by spray pyrolysis technique. The films were studied after annealing
in air at temperatures 550°C, 750°C and 950°C for 30 min. The films were characterized by X-ray diffraction (XRD), scanning
electron microscopy (SEM) and optical absorption spectroscopy technique. The grain size was observed to increase with the
increase in annealing temperature. Absorbance spectra were taken to examine the optical properties and bandgap energy was
observed to decrease with the increase in annealing temperature. These films were tested in various gases at different operating
temperatures ranging from 50–450°C. The film showed maximum sensitivity to H 2S gas. The H2S sensing properties of the SnO2 films were investigated with different annealing temperatures and H 2S gas concentrations. It was found that the annealing temperature significantly affects the sensitivity of the SnO2 to the H 2S. The sensitivity was found to be maximum for the film annealed at temperature 950°C at an operating temperature of 100°C.
The quick response and fast recovery are the main features of this film. The effect of annealing temperature on the optical,
structural, morphological and gas sensing properties of the films were studied and discussed. 相似文献
2.
This paper reports the synthesis of SnO2-CuO, SnO2-Fe2O3 and SnO2-SbO2 composites of nano oxides and comparative study of humidity sensing on their electrical resistances. CuO, Fe2O3 and SbO2 were added within base material SnO2 in the ratio 1: 0.25, 1: 0.50 and 1: 1. Characterizations of materials were done using SEM and XRD. SEM images show the surface
morphology and X-ray diffraction reveals the nanostructure of sensing materials. The pellets were annealed at 200, 400 and
600°C respectively for 3 h and after each step of annealing, observations were carried out. It was observed that as relative
humidity (%RH) increases, there was decrease in the resistance of pellet for the entire range of RH. Results were found reproducible.
SnO2-SbO2 shows maximum sensitivity for humidity (12 MΩ/%RH) among other composites. 相似文献
3.
Ravi Chand Singh Nipin Kohli Manmeet Pal Singh Onkar Singh 《Bulletin of Materials Science》2010,33(5):575-579
The sensing response of pure and SnO2 activated Cr2O3 to ethanol vapours and liquefied petroleum gas (LPG) has been investigated. Fine particles of commercial chromium oxide powder
were selected and deposited as thick film to act as a gas sensor. The sensor surface has been activated by tin dioxide, on
surface oxidation of tin chloride. The concentration of tin chloride solution, used as activator, was varied from 0 to 5%
and its effect on gas response, selectivity and operating temperature has been studied. It was found that response to ethanol
vapours significantly improved, whereas response to LPG remained unaffected. Moreover, operating temperature remains unchanged
both for LPG and ethanol vapours. 相似文献
4.
Gurpreet Singh Maninder Kaur Bindiya Arora Ravi Chand Singh 《Journal of Materials Science: Materials in Electronics》2018,29(2):867-875
In this paper we report doping induced enhanced sensor response of SnO2 based sensor towards ethanol at a working temperature of 200 °C. Undoped and dysprosium-doped (Dy-doped) SnO2 nanoparticles were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). XRD and Raman results verified tetragonal rutile structure of the prepared samples. It has been observed that crystallite size reduced with increase in dopant concentration. In addition, the particle size has been calculated from Raman spectroscopy using phonon confinement model and the values match very well with results obtained from TEM and X-ray diffraction investigations. Dy-doped SnO2 sensors exhibited significantly enhanced response towards ethanol as compared to undoped sensor. The optimum operating temperature of doped sensor reduced to 200 °C as compared to 320 °C for that of undoped sensor. Moreover, sensor fabricated from Dy-doped SnO2 nanostructures was highly selective toward ethanol which signifies its potential use for commercial applications. The gas sensing mechanism of SnO2 and possible origin of enhanced sensor response has been discussed. 相似文献
5.
R. S. Khadayate R. B. Waghulde M. G. Wankhede J. V. Sali P. P. Patil 《Bulletin of Materials Science》2007,30(2):129-133
This paper presents ethanol vapour sensing properties of WO3 thick films. In this work, the WO3 thick films were prepared by standard screen-printing method. These films were characterized by X-ray diffraction (XRD) measurements
and scanning electron microscopy (SEM). The ethanol vapour sensing properties of these thick films were investigated at different
operating temperatures and ethanol vapour concentrations. The WO3 thick films exhibit excellent ethanol vapour sensing properties with a maximum sensitivity of ∼1424.6% at 400°C in air atmosphere
with fast response and recovery time. 相似文献
6.
We report a physicochemical study of the formation of thin-film and particulate SnO2〈Sb〉 materials from film-forming solutions of Sn(II) and Sb(III) complexes during heat treatment and describe the electrical and gas-sensing properties of the films. The particle size and antimony concentration are shown to have a significant effect on carbon monoxide adsorption by the synthesized materials. 相似文献
7.
Current–voltage characteristics, temperature dependences of the low-field dc conductivity and the relative dielectric permittivity
of tin dioxide based SnO2–Co3O4–Nb2O5–Cr2O3 ceramics with CuO addition in the range 0–8 mol% are studied. These materials exhibit non-Ohmic conduction (the varistor
effect). If 0.5 mol% CuO is added, the nonlinearity coefficient is increased from 54 to 75 and the electric field at fixed
current density is decreased from 628 to 390 kV m−1. Higher amounts of CuO substantially diminish non-Ohmic behaviour. Thickness dependence of the nonlinearity coefficient and
the electric field at fixed current density in SnO2 varistor ceramics is observed. Electrical properties are discussed in the frames of grain-boundary controlled conduction
mechanism. 相似文献
8.
Xiang-bin Kong Fang Li Zhong-nan Qi Lei Qi Ming-ming Yao 《Journal of Materials Science: Materials in Electronics》2017,28(11):7660-7667
SnO2 semiconductor is a new-typed promising photocatalyst, but wide application of SnO2-based photocatalytic technology has been restricted by low visible light utilization efficiency and rapid recombination of photogenerated electrons–holes. To overcome these drawbacks, we prepared B/Fe codoped SnO2–ZnO thin films on glass substrates through a simple sol–gel method. The photocatalytic activities of the films were evaluated by degradation of organic pollutants including acid naphthol red (ANR) and formaldehyde. UV–Vis absorption spectroscopy and photoluminescence (PL) spectra results revealed that the B/Fe codoped SnO2–ZnO film not only enhanced optical absorption properties but also improved lifetime of the charge carriers. X-ray diffraction (XRD) results indicated that the nanocrystalline SnO2 was a single crystal type of rutile. Field emission scanning electron microscopy (FE-SEM) results showed that the B/Fe codoped SnO2–ZnO film without cracks was composed of smaller nanoparticles or aggregates compared to pure SnO2 film. Brunauer–Emmett–Teller (BET) surface area results showed that the specific surface area of the B/Fe codoped SnO2–ZnO was 85.2 m2 g?1, while that of the pure SnO2 was 20.7 m2 g?1. Experimental results exhibited that the B/Fe codoped SnO2–ZnO film had the best photocatalytic activity compared to a pure SnO2 or singly-modified SnO2 film. 相似文献
9.
F. I. Shaikh L. P. Chikhale I. S. Mulla S. S. Suryavanshi 《Journal of Materials Science: Materials in Electronics》2017,28(4):3128-3139
In the present paper we have synthesized pristine and Sr doped SnO2 in order to prepare a selective ethanol sensor with rapid response–recovery time and good repeatability. Pristine as well as Sr (2, 4 and 6 mol%) doped SnO2 nanostructured powder was synthesized by using a facile co-precipitation method. The samples were characterized by TG–DTA, XRD, HR-TEM, SAED, FEG-SEM, SEM–EDAX, XPS, UV–Vis and FTIR spectroscopy techniques. The gas response performance of sensor towards ethanol, acetone, liquid petroleum gas and ammonia has been carried out. The results demonstrate that Sr doping in SnO2 systematically decreases crystallite size, increases the porosity and hence enhances the gas response properties of pristine SnO2 viz. lower operating temperature, higher ethanol response and better selectivity towards ethanol. The response and recovery time for 4 mol% Sr doped SnO2 thick film sensor at the operating temperature of 300 °C were 2 and 7 s, respectively. 相似文献
10.
S. M. Badalyan M. N. Rumyantseva S. A. Nikolaev A. V. Marikutsa V. V. Smirnov A. S. Alikhanian A. M. Gaskov 《Inorganic Materials》2010,46(3):232-236
Nanocrystalline tin dioxide has been synthesized, and its surface has been modified with Au and NiO. Their distributions in
the nanocrystalline tin dioxide have been examined by X-ray diffraction and transmission electron microscopy. The NO2 sensing properties of the materials have been studied in the range 100–1000 ppb. Both gold and nickel enhance the NO2 response of SnO2. Codoping with Au and NiO markedly enhances its sensing response and, in addition, lowers the peak response temperature.
The observed effect of NO2 concentration in dry air on the sensing response of the SnO2〈Au, NiO〉 nanocomposite can be understood in terms of the sequence of processes that take place on the SnO2 surface upon nitrogen dioxide adsorption in the presence of chemisorbed oxygen. 相似文献
11.
Mohammad Maleki Shahraki Seyyed Ali Shojaee Ali Nemati Mohammad Ali Faghihi Sani 《Journal of Materials Science: Materials in Electronics》2010,21(2):199-205
In this study, SnO2-based varistors were prepared from mechanically activated nanocrystalline powders. Nanocrystalline powders were derived by
subjecting the initial powders to intensive high-energy activation with different times and ball to powder ratio. The effect
of activation parameters on the powder properties and sintering temperature, as well as microstructural, micro-electrical
and macro-electrical properties of the final specimens was evaluated. Varistors derived from high-energy mechanical activation
exhibit a higher density (98.3% relative density) and more refined microstructure upon sintering at 1,300 °C in comparison
varistors prepared from conventional powders. Breakdown voltage and nonlinear coefficient were increased up to 24 kV/cm and
45 respectively. 相似文献
12.
Alternating current (a.c.) electrical properties of thermally evaporated amorphous thin films of SnO2 sandwiched between aluminium electrodes have been investigated for temperature during electrical measurements, film thickness,
substrate temperature and post-deposition annealing. The a.c. conductivity, σ(ω), is found to vary with frequency according
to the relation σ(ω) ∝ ωs, indicating a hopping process at low temperature. The conduction is explained by single polaron hopping process as proposed
by Elliott. The increase in electrical conductivity with increase in temperature during electrical measurements is ascribed
to the increase in the formation and high mobility of doubly ionized oxygen vacancies. The increase in conductivity with increase
in film thickness is caused by the increase in interstitial tin, oxygen vacancies and defects produced due to deviation from
stoichiometry. The increase in conductivity with increase in substrate and annealing temperature may be due to the formation
of singly or doubly ionized oxygen vacancies and tin species of lower oxidation state. Measurements of capacitance C as a function of frequency and temperature show a decrease in C with increasing frequency and increase in C with increasing temperature. The increase in capacitance in the high-temperature low-frequency region is probably due to
space charge polarization induced by the increasing number of free carriers as a result of increasing temperature. 相似文献
13.
P. A. Chate D. J. Sathe P. P. Hankare 《Journal of Materials Science: Materials in Electronics》2011,22(2):111-115
A dip method is employed for the deposition of CdSe0.5S0.5 composite thin film at room temperature. Cadmium sulphate, thiourea and sodium selenosulphate were used as the basic source
material. Solid solution with cubic phase was observed from X-ray diffraction studies. The specific conductivity of the film
was found to be in order of 10−7 (Ωcm)−1. The temperature dependence of an electrical conductivity, thermoelectrical power, carrier density and carrier mobility for
CdSe0.5S0.5 thin films have been examined. The low temperature conductivity is governed by a variable range of conduction while grain
boundary limited conduction mechanism is predominant at higher temperature. 相似文献
14.
15.
Er-doped SnO2 thin films, obtained by sol-gel-dip-coating technique, were submitted to excitation with the 4th harmonic of a Nd:YAG laser
(266 nm), at low temperature, and a conductivity decay is observed when the illumination is removed. This decay is modeled
by considering a thermally activated cross section of an Er-related trapping center. Besides, grain boundary scattering is
considered as dominant for electronic mobility. X-ray diffraction data show a characteristic profile of nanoscopic crystallite
material (grain average size ≈5 nm) in agreement with this model. Temperature dependent and concentration dependent decays
are measured and the capture barrier is evaluated from the model, yielding 100 meV for SnO2:0.1% Er and 148 meV for SnO2:4% Er. 相似文献
16.
The characterization and ethanol gas sensing properties of pure and doped ZnO thick films were investigated. Thick films of
pure zinc oxide were prepared by the screen printing technique. Pure zinc oxide was almost insensitive to ethanol. Thick films
of Al2O3 (1 wt%) doped ZnO were observed to be highly sensitive to ethanol vapours at 300°C. Aluminium oxide grains dispersed around
ZnO grains would result into the barrier height among the grains. Upon exposure of ethanol vapours, the barrier height would
decrease greatly leading to drastic increase in conductance. It is reported that the surface misfits, calcination temperature
and operating temperature can affect the microstructure and gas sensing performance of the sensor. The efforts are, therefore,
made to create surface misfits by doping Al2O3 into zinc oxide and to study the sensing performance. The quick response and fast recovery are the main features of this
sensor. The effects of microstructure and additive concentration on the gas response, selectivity, response time and recovery
time of the sensor in the presence of ethanol vapours were studied and discussed. 相似文献
17.
The nonlinear current (I)-voltage (V) characteristics of tin dioxide doped with either Nb2O5 and CoO or Sb2O3 and CoO show promising values of nonlinear coefficient (α) values (∼11) with low breakdown voltages (E
B, ∼40 V mm−1). The pentavalent antimony or niobium acts as donor and increases the electronic conductivity. The crucial parameter for
obtaining low breakdown voltage is the grain size, which depends upon sintering duration and temperature of these oxide ceramics. 相似文献
18.
N. Manjula G. Selvan 《Journal of Materials Science: Materials in Electronics》2017,28(20):15056-15064
Zirconium doped tin oxide (SnO2:Zr) nanopowders were synthesized by a simple soft chemical route adding various concentrations of zirconyl chloride (0, 5, 10 and 15 wt%). The samples were characterized by techniques like XRD, SEM, TEM, EDX, FTIR spectroscopy, UV–Vis-NIR spectroscopy and photoluminescence spectroscopy. XRD studies confirm that all the samples exhibit rutile tetragonal crystal structure with a strong (1 0 1) preferential growth texture. Hexagonal shaped grains were evinced from the SEM images. Nanosized grains are evinced from the TEM images and EDX spectra confirm the presence of Zr in the doped samples. The bands at 523 and 583 cm?1 observed in the FTIR spectra which are attributed as the characteristics of γ (Sn–OH) terminal bond of the SnO2 crystalline phase confirm the presence of Sn–O in the synthesized samples. The doped samples exhibit ferromagnetic behavior. Enhanced antibacterial activity was observed for the doped samples. The obtained results show that zirconium strongly influenced the structural, morphological, optical, magnetic and antibacterial properties of pure SnO2 nanopowders. 相似文献
19.
Sandra A. Mayén-Hernández Gerardo Torres-Delgado Rebeca Castanedo-Pérez Mario Gutiérrez Villarreal Alfredo Cruz-Orea Julio G. Mendoza Alvarez Orlando Zelaya-Angel 《Journal of Materials Science: Materials in Electronics》2007,18(11):1127-1130
ZnO + Zn2TiO4 thin films were obtained by the sol–gel method using precursor solutions with different Ti/Zn ratios in the 0.18–2.13 range.
The films were deposited on glass substrates and annealed in an open atmosphere at 550 °C. The oxide was characterized by
X-ray diffraction and photoacoustic (PA) spectroscopy. The films were constituted of polycrystalline ZnO for the lowest Ti/Zn
ratio (0.18), polycrystalline Zn2TiO4 for the 0.70 and 1.0 ratios, and mixes of both oxides for the intermediate ratios (0.32 and 0.50). For the highest ratios
studied (1.44 and 2.13), the films were amorphous. The energy band gap (Eg) values were determined from optical absorption spectra, measured by means of the PA technique spectra. Eg varied in the 3.15 eV (ZnO) to 3.70 eV (Zn2TiO4) range. 相似文献
20.
SnO2/MoO3 nanocomposites are synthesized in a broad composition range through chemical precipitation from solution, and their phase composition and microstructure are investigated by x-ray diffraction. The gas sensitivity of the nanocomposites to lower alcohols (CnH2n + 1 OH, n=1–4) is studied by in situ conductance measurements. The results are interpreted in terms of the acid-base properties of the nanocomposite surface.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 4, 2005, pp. 442–449.Original Russian Text Copyright © 2005 by Makeeva, Rumyantseva, Gaskov. 相似文献