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1.
M Zarrinkhameh A Zendehnam S M Hosseini N Robatmili M Arabzadegan 《Bulletin of Materials Science》2014,37(3):533-539
Tin oxide thin films were deposited on glass substrate with 100 nm thickness of Sn, which was coated by magnetron sputtering followed by thermal oxidation at different temperatures. The effect of oxidation temperature on the optical and structural properties of SnO2 films were investigated. Higher transmittance, lower absorption and lesser structural defects were obtained at higher temperatures. Optical bandgap increases with temperature, while the Urbach energy showed reduction. The X-ray diffraction studies showed that at lower temperatures (300, 350 °C), a combined phase of SnO and SnO2 was obtained, while at higher temperatures (400, 450 °C), a nearly polycrystalline SnO2 film with preferred orientation of (101) was produced. Annealing of the samples at 500–650 °C caused the transmittance and optical bandgap increased, while the absorption decreased. Reduction of the Urbach energy after annealing could be attributed to the reduction of the degree of thermal disorder. AFM studies showed that although the thin films were annealed under similar condition, their roughness was not similar because of different oxidation temperatures, which means that initial oxidation temperature played an important role on surface uniformity of SnO2 thin films. 相似文献
2.
Pure SnO2 films and Ag-, Cu-, Pt-, and Pd-doped SnO2 films were investigated for H2S sensing properties. SnO2 films were deposited by DC magnetron sputtering at various substrate temperatures and discharge gas pressures. As the discharge gas pressure increased and the substrate temperature decreased, the film became porous. Doping with Cu or Ag film improved the sensitivity, and the highest sensitivity was obtained in the porous SnO2 film coated with an Ag film 16 nm thick. According to the X-ray diffraction (XRD) pattern, Ag deposited on SnO2 film transformed to Ag2S upon exposure to H2S. When the Ag-doped film sensor was operated at a low temperature, the sensitivity was extremely high, but the recovery was insufficient. By increasing the operation temperature, the recovery was improved but the sensitivity decreased. 相似文献
3.
C. Sankar V. Ponnuswamy M. Manickam R. Suresh R. Mariappan P. S. Vinod 《Journal of Materials Science: Materials in Electronics》2017,28(6):4577-4585
Pure and cerium (Ce) doped tin oxide (SnO2) thin films are prepared on glass substrates by jet nebulizer spray pyrolysis technique at 450 °C. The synthesized films are characterized by X-ray diffraction (XRD), scanning electron microscopy, energy dispersive analysis X-ray, ultra violet visible spectrometer (UV–Vis) and stylus profilometer. Crystalline structure, crystallite size, lattice parameters, texture coefficient and stacking fault of the SnO2 thin films have been determined using X-ray diffractometer. The XRD results indicate that the films are grown with (110) plane preferred orientation. The surface morphology, elemental analysis and film thickness of the SnO2 films are analyzed and discussed. Optical band gap energy are calculated with transmittance data obtained from UV–Visible spectra. Optical characterization reveals that the band gap energy is found decreased from 3.49 to 2.68 eV. Pure and Ce doped SnO2 thin film gas sensors are fabricated and their gas sensing properties are tested for various gases maintained at different temperature between 150 and 250 °C. The 10 wt% Ce doped SnO2 sensor shows good selectivity towards ethanol (at operating temperature 250 °C). The influence of Ce concentration and operating temperature on the sensor performance is discussed. The better sensing ability for ethanol is observed compared with methanol, acetone, ammonia, and 2-methoxy ethanol gases. 相似文献
4.
Wen-Ching Shih Ming-Han Chiang 《Journal of Materials Science: Materials in Electronics》2010,21(8):844-848
In this paper, BaTiO3 thin films were prepared by RF magnetron sputtering on MgO substrates and their properties such as the crystal structure
and optical waveguide properties were investigated. The optimum deposition parameters, such as substrate temperature, deposition
pressure, gas flow ratio, the RF power and the after annealing temperature, were obtained in order to get the best BaTiO3 film quality. The XRD results show that highly c-axis textured BaTiO3 thin films were successfully grown on MgO substrate. Films obtained under the optimum deposition parameters, substrate temperature
of 650°C, RF power of 50 W, deposition pressure 18 mTorr and gas flow ratio O2/(Ar+ O2) of 15% namely, reaches a full width at half maximum intensity (FWHM) of BaTiO3 (002) XRD peak of 0.25°. The FWHM of BaTiO3 (002) XRD peak was further reduced to 0.24° via post-treatment with furnace annealing (at 800°C for 2 h) which indicates
the film crystal quality is further improved. The bright and sharp TE modes measured by m-line spectroscopy of the BaTiO3 film were observed indicating its possible application in optical waveguide. 相似文献
5.
Anil D. Garje Rohini C. Aiyer 《Journal of Materials Science: Materials in Electronics》2008,19(6):547-552
Synthesized nanophase SnO2 powder was used as a functional material along with optimized 15 wt% of glass, fired at 550 °C for better adhesion, to fabricate
thick films using screen printing on alumina substrate. Their surface was modified by dip coating in platinum chloride solution
(PtCl2) of different molarities (0.05–0.2 M). A subsequent thermal treatment to these thick films was carried out at an optimized
temperature of 750 °C in air atmosphere. The films were tested for 400 ppm concentration of H2, CO and LPG. Sensors dip coated with 0.15 M solution of PtCl2 show the highest sensitivity towards the test gases which is ten times higher than undoped SnO2 sensors.XRD, EDX and SEM measurements showed that the behavior could be associated with the spatial distribution of the platinum
within the tin oxide film. The sensors have fast response time of 10 s to all the three gases with a minimum detection limit
of 10 ppm. 相似文献
6.
E. Yucel Cabir Terzioglu A. Varilci I. Belenli 《Journal of Materials Science: Materials in Electronics》2011,22(8):1143-1153
We have fabricated MgB2/Fe monofilament wires and tapes by a powder-in tube (PIT) technique, using an ex-situ process without any intermediate annealing.
MgB2/Fe monofilament tapes were annealed at 650–1,050°C for 60 min and 950°C for 30–240 min. We have investigated the effect of
annealing temperatures and times on the formation of MgB2 phase, activation energy, temperature dependence of irreversibility field H
irr(T) and upper critical field H
c2(T), transition temperature (T
c), lattice parameters (a and c), full width at half maximum, crystallinity, resistivity, residual resistivity ratio, active cross-sectional area fraction
and critical current densities. We observed that the activation energies of the MgB2/Fe monofilament samples increased with increasing annealing temperature up to 950°C and with increasing annealing time up
to 60 min while it decreased with increasing magnetic field. For the MgB2/Fe monofilament tape, the slope of the H
c2–T and H
irr–T curves decreased with increasing annealing temperature from 850 to 950°C as well as with increasing annealing time from 30
to 60 min. The transport and microstructure investigations show that T
c, J
c and microstructure properties are remarkably enhanced with increasing annealing temperature. The highest value of critical
current density is obtained for the sample annealed at 950°C for 60 min. The J
c and T
coffset values of the sample annealed at 950°C for 60 min were found to be 260.43 A/cm2 at 20 and 38.1 K, respectively. 相似文献
7.
《Thin solid films》1999,337(1-2):163-165
Polycristalline Pt-doped SnO2 thin films have been integrated to silicon substrate by ultrasonic spray deposition. This deposition technique differs from the usual SnO2 deposition methods by using a liquid source. It allows one to obtain a very fine and homogeneous dispersion of Pt aggregates which act as a catalyst for the low temperature CO detection (25–100°C) by conductance change. The influence of synthesis temperature (460–560°C), concentration of Pt additive (0.1–5 at.%) on gas sensitivity has been studied. The realisation of gas sensor includes a gas sensitive highly porous layer (SnO2/Pt, thickness: ∼1 μm). The results of electrical measurements under 300 ppm of CO for thin films in a dynamic and quasistatic regime are discussed. The narrow peak of gas sensitivity in the range of low temperatures (25–100°C) is obtained for about 2 at.% Pt in the SnO2 film. 相似文献
8.
In the present study, different catalysts (∼ 10 nm thick) including metals, noble metals and metal oxides, were loaded in
dotted island form over SnO2 thin film for LPG gas detection. A comparison of various catalysts indicated that the presence of platinum dotted islands
over SnO2 thin film deposited by r.f. sputtering exhibited enhanced response characteristics with a high sensitivity, ∼ 742, at an
operating temperature of ∼ 280°C. Different characterization techniques have been employed such as atomic force microscopy,
X-ray diffraction and UV-vis spectroscopy, to study the surface morphology, grain size and optical properties of the deposited
thin films. The results suggest the possibility of utilizing the sensor element with the present novel method of catalyst
dispersal for the efficient detection of LPG. 相似文献
9.
V. Senthilkumar P. Vickraman 《Journal of Materials Science: Materials in Electronics》2010,21(6):578-583
Nanocrystalline tin oxide (SnO2) thin films were coated using electron beam evaporation technique on glass substrates. To study the gleaming out look of
the structure and surface morphological changes, the films were annealed in the temperature 350–550 °C for 1 h. The annealed
films were subjected to X-ray diffraction (XRD) and atomic force microscopy (AFM) studies. The XRD patterns of SnO2 thin films as-deposited and annealed at 350 °C illustrate that the films were amorphous, and beyond 350 °C and thereafter
they became polycrystalline with tetragonal structure. The crystallite size of the annealed films, obtained through the XRD
analysis, increased with the increasing annealing temperature, and it was found to be from 3.6 to 12 nm. The photoluminescence
(PL) studies on these films were also carried out. The origin of luminescence was assigned to the defects of the nanocrystalline
SnO2 films. The Optical studies (UV-VIS) were performed and the optical band gab energy (Eg) calculations, the dependence of absorption
coefficient on the photon energy at short wavelengths, were found to be increasing from 3.65 to 3.91 eV is also investigated. 相似文献
10.
Yu. M. Chesnokov A. V. Miakonkikh A. E. Rogozhin K. V. Rudenko A. L. Vasiliev 《Journal of Materials Science》2018,53(10):7214-7223
The influence of annealing in the temperature range of 150–300 °C during plasma-enhanced atomic layer deposition of HfO2 and the conditions of the following thermal processing on microstructure and electrical properties have been studied. The microstructure was examined by transmission electron microscopy and electron diffraction. The as-deposited HfO2 film consists of monoclinic crystallites embedded in an amorphous matrix. It was found that the crystallite density grows with the increase in the deposition temperature; however, the size of the crystallites does not change. Subsequent annealing at 425 °C for 30 min or at 950 °C for 4 s led to complete crystallization through the lateral growth of the crystallites of samples formed at 250 and 300 °C. However, for the sample formed at 150 °C, subsequent annealing at 425 °C resulted in the formation of dendritic-like crystalline clusters embedded in an amorphous matrix. The leakage currents in polycrystalline and even amorphous HfO2 films after the annealing were drastically increased. That could be explained by crystallization after the annealing. However, the C impurity redistribution and the growth of an interfacial layer could also affect the leakage. 相似文献
11.
K NOMURA H SHIOZAWA T TAKADA H REUTHER E RICHTER 《Journal of Materials Science: Materials in Electronics》1997,8(5):301-306
SnO2 gas-sensor films were modified by implantation of gold and iron ions. The change in electrical resistivity of the films caused
by inflammable gases, H2, CO, CH4 and C2H5OH, was measured in the temperature range 100–500°C, and compared to non-implanted films. The morphological changes caused
by gold and iron ion implantation were also investigated by atomic force microscopy. After ion implantation and annealing
at 600°C, the sensitivity to H2 and CO gas was found to increase, and the dynamic range of the sensitivity to ethanol was improved. The sensitivity to CH4 was low before and after ion implantation. Fe2O3 (3%SnO2) film was also modified by gold ion implantation for comparison.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Hock Jin Quah Kuan Yew Cheong Zainuriah Hassan Zainovia Lockman 《Journal of Materials Science: Materials in Electronics》2011,22(6):583-591
The effects of post-deposition annealing temperatures (400, 600, 800, and 1,000°C) in forming gas (95% N2 + 5% H2) ambient on metal–organic decomposed cerium oxide (CeO2) thin films deposited on n-type GaN substrate had been investigated. The occurrence of CeO2 phase transformation was reported and presence of CeO2, α-Ce2O3, and β-Ga2O3 had been detected, depending on the annealing temperature. As the annealing temperature increased, grain size and microstrains
of CeO2 films were, respectively, increased and reduced. Metal–oxide–semiconductor characteristics of the annealed samples were systematically
investigated. The highest dielectric breakdown field was perceived by sample annealed at 400°C due to the reduction of semiconductor–oxide
interface trap density and effective oxide charge. 相似文献
13.
For the first time, sputtered zinc oxide (ZnO) thin films have been used as a CO2 gas sensor. Zinc oxide thin films have been synthesized using reactive d.c. sputtering method for gas sensor applications,
in the deposition temperature range from 130–153°C at a chamber pressure of 8·5 mbar for 18 h. Argon and oxygen gases were
used as sputtering and reactive gases, respectively. ZnO phase could be crystallized using a pure metal target of zinc. The
structure of the films determined by means of X-ray diffraction method indicates that the zinc oxide single phase can be fabricated
in this substrate temperature range. The sensitivity of the film synthesized at substrate temperature of 130°C is 2·17 in
the presence of CO2 gas at a measuring temperature of 100°C. 相似文献
14.
Miguel Adolfo Ponce Rodrigo Parra Miriam S. Castro Celso M. Aldao 《Journal of Materials Science: Materials in Electronics》2007,18(12):1171-1177
Thick films prepared with undoped nanometric SnO2 particles and with (Co, Nb, Fe)-doped SnO2 were studied with the purpose of developing oxygen and carbon monoxide gas sensors. The ceramic powders were obtained through
the Pechini method. The morphological characteristics were studied with SEM and TEM, after which, they were subjected to sensitivity
tests under different atmospheres. A correlation was established between the microstructure of the material, the effects of
the additives, and the electrical behavior. The response of the sensor could be explained as the result of the characteristics
of the intergranular potential barriers developed at intergrains. It was determined that the SnO2-doped films have a greater sensitivity between 200 °C and 350 °C. 相似文献
15.
Yuanda Liu Xiaochuan Xia Hongwei Liang Hezhi Zhang Jiming Bian Yang Liu Rensheng Shen Yingmin Luo Guotong Du 《Journal of Materials Science: Materials in Electronics》2012,23(2):542-545
Ga2O3 thin films were deposited on sapphire (0001) substrates by low-pressure metal organic chemical vapor deposition. The influence
of annealing in N2 atmosphere at the temperature in the range of 800–1,000 °C was investigated by X-ray diffraction and optical transmittance
spectra. With an increase of annealing temperature from 800 to 950 °C, the transformation from the initial amorphous film
to polycrystalline β-Ga2O3 thin film was observed, and the transmittance was also improved remarkably. The optical band gap energy of the sample annealed
at 950 °C was evaluated as ~5 eV. Whereas, after an annealing at 1,000 °C, the crystal quality became worse and the transmittance
degraded. The mechanism of annealing in N2 atmosphere was discussed in view of phase transition. 相似文献
16.
A. B. Bodade Minaz Alvi A. V. Kadu G. N. Chaudhari 《Journal of Materials Science》2010,45(19):5264-5270
Nanocrystalline La1−x
Co
x
Mn1−y
Ni
y
O3 (x = 0.2 and 0.4; y = 0.1, 0.3, and 0.5) thick films sensors prepared by sol–gel method were studied for their H2S gas sensitivity. The structural and morphological properties have been carried out by X-ray diffraction (XRD) and transmission
electron microscopy (TEM). Average particle size estimated from XRD and TEM analyses was observed to be 30–35 nm. The gas
response characteristics were found to depend on the dopants concentration and operating temperature. The maximum H2S gas response of pure LaMnO3 was found to be at 300 °C. In order to improve the gas response, material doped with transition metals Co and Ni on A- and
B-site, respectively. The La0.6Co0.4Mn0.5Ni0.5O3 shows high response towards H2S gas at an operating temperature 250 °C. The Pd-doped La0.6Co0.4Mn0.5Ni0.5O3 sensor was found to be highly sensitive to H2S at an operating temperature 200 °C. The gas response, selectivity, response time and recovery time were studied and discussed. 相似文献
17.
Talaat A. Hameed Wei Cao E. M. Abdelrazek I. K. El Zawawi B. A. Mansour Hani E. Elsayed-Ali 《Journal of Materials Science: Materials in Electronics》2016,27(4):3209-3216
Cu(In, Ga, Al)Se2 (CIGAS) thin films were deposited by magnetron sputtering on Si(100) and soda-lime glass substrates at different substrate temperatures, followed by post-deposition annealing at 350 or 520 °C for 5 h in vacuum. Electron probe micro-analysis and secondary ion mass spectroscopy were used to determine the composition of the films and the distribution of Al across the film thickness, respectively. X-ray diffraction analysis showed that the (112) peak of CIGAS films shifts to higher 2θ values with increasing substrate temperature but remains unchanged when the films were annealed at 520 °C for 5 h. Scanning electron microscopy and atomic force microscopy images revealed dense and well-defined grains for both as-deposited and annealed films. However, notable increase in grain size and roughness was observed for films deposited at 500 °C. The bandgap of CIGAS films was determined from the optical transmittance and reflectance spectra and was found to increase as the substrate temperature was increased. 相似文献
18.
Wen Chiao Chin Kuan Yew Cheong 《Journal of Materials Science: Materials in Electronics》2011,22(12):1816-1826
Samarium oxide (Sm2O3) thin films with thicknesses in the range of 15–30 nm are deposited on n-type silicon (100) substrate via radio frequency
magnetron sputtering. Effects of post-deposition annealing ambient [argon and forming gas (FG) (90% N2 + 10% H2)] and temperatures (500, 600, 700, and 800 °C) on the structural and electrical properties of deposited films are investigated
and reported. X-ray diffraction revealed that all of the annealed samples possessed polycrystalline structure with C-type
cubic phase. Atomic force microscope results indicated root-mean-square surface roughness of the oxide film being annealed
in argon ambient are lower than that of FG annealed samples, but they are comparable at the annealing temperature of 700 °C
(Argon—0.378 nm, FG—0.395 nm). High frequency capacitance–voltage measurements are carried out to determine effective oxide
charge, dielectric constant and semiconductor-oxide interface trap density of the annealed oxide films. Sm2O3 thin films annealed in FG have smaller amount of effective oxide charge and semiconductor-oxide interface trap density than
those oxide films annealed in argon. Current–voltage measurements are conducted to obtain barrier heights of the annealed
oxide films during Fowler–Nordheim tunneling. 相似文献
19.
Mohammed K. Al-hashimi Burak Y. Kadem Aseel K. Hassan 《Journal of Materials Science: Materials in Electronics》2018,29(9):7152-7160
Titanium dioxide (TiO2) thin films were prepared by sol–gel spin coating method and deposited on ITO-coated glass substrates. The effects of different heat treatment annealing temperatures on the phase composition of TiO2 films and its effect on the optical band gap, morphological, structural as well as using these layers in P3HT:PCBM-based organic solar cell were examined. The results show the presence of rutile phases in the TiO2 films which were heat-treated for 2 h at different temperatures (200, 300, 400, 500 and 600 °C). The optical properties of the TiO2 films have altered by temperature with a slight decrease in the transmittance intensity in the visible region with increasing the temperature. The optical band gap values were found to be in the range of 3.28–3.59 eV for the forbidden direct electronic transition and 3.40–3.79 eV for the allowed direct transition. TiO2 layers were used as electron transport layer in inverted organic solar cells and resulted in a power conversion efficiency of 1.59% with short circuit current density of 6.64 mA cm?2 for TiO2 layer heat-treated at 600 °C. 相似文献
20.
Adeleh Hashemi Ali Bahari Shahram Ghasemi 《Journal of Materials Science: Materials in Electronics》2017,28(18):13313-13319
In the present study, povidone-SiO2 nano-composite dielectric film was introduced to replace SiO2 gate dielectric film. The organic and inorganic particles homogeneously dispersed in nano-composite film. The structure of nano-composite film was affected by annealing temperatures. By increase in annealing temperature up to 200?°C, wt% of carbon, oxygen and nitrogen increased and wt% of silicon decreased. At 240?°C, the organic phase desorbed and nano-composite structure degraded. The annealing temperature of 150?°C was suitable for adhesion between two phases. The cross-linked structure of dielectric film annealed at 150?°C led to decrease in leakage current. 相似文献