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1.
We have studied the influence of synthesis temperature on chemical composition and mechanical properties of X-ray amorphous boron-oxygen-hydrogen (B-O-H) films. These B-O-H films have been synthesized by RF sputtering of a B-target in an Ar atmosphere. Upon increasing the synthesis temperature from room temperature to 550 °C, the O/B and H/B ratios decrease from 0.73 to 0.15 and 0.28 to 0.07, respectively, as determined by elastic recoil detection analysis. It is reasonable to assume that potential sources of O and H are residual gas and laboratory atmosphere. The elastic modulus, as measured by nanoindentation, increases from 93 to 214 GPa, as the O/B and H/B ratios decreases within the range probed. Hence, we have shown that the effect of impurity incorporation on the elastic properties is extensive and that the magnitude of the incorporation is a strong function of the substrate temperature. 相似文献
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《Materials Research Bulletin》2006,41(9):1596-1603
Anatase TiO2 thin films were successfully prepared on glass slide substrates via a sol–gel method from refluxed sol (RS) containing anatase TiO2 crystals at low temperature of 100 °C. The influences of various refluxing time on crystallinity, morphology and size of the RS sol and dried TiO2 films particles were discussed. These samples were characterized by infrared absorption spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission-scanning electron microscopy (FE-SEM) and UV–vis absorption spectroscopy (UV–vis). The photocatalytic activities of the TiO2 thin films were assessed by the degradation of methyl orange in aqueous solution. The results indicated that titania films thus obtained were transparent and their maximal light transmittance exceeded 80% under visible light region. The TiO2 thin films prepared from RS-6 sol showed the highest photocatalytic activity, when the calcination temperature is higher than 300 °C. The degradation of methyl orange of RS-6 thin films reached 99% after irradiated for 120 min, the results suggested that the TiO2 thin films prepared from RS sol exhibited high photoactivities. 相似文献
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We report here the results of an extensive study of localization and electron-electron interaction effects in thin cadmium films with thickness ranging from 80 Å to 350 Å. Measurements of the resistance as a function of both temperature and magnetic field have allowed us to separate the contributions of localization and electron-electron interaction. The low resistive films of thicknesses 300 Å and 350 Å do not show any localization. The resistance of these samples decreases logarithmically with decreasing temperature below 10 K, while a ln(T) increases in resistance is observed for the high resistive films of thickness in the range of 80–120 Å. Magnetoresistance of low resistive samples obeys the expression R(H)/R(O)=AT
n. But, both the resistance and magnetoconductance of the high resistive films are well explained by weak localization and electron-electron interaction effect. From the magnetoconductance measurement, we have calculated the inelastic scattering time (
i
) and the spin-orbit scattering time (
so
). The magnitude of spin-orbit scattering time is smaller than the inelastic scattering time. The inelastic scattering has been shown to arise due to the electron-electron scattering and the absolute magnitude of this scattering rate agrees reasonably well with the theory within the temperature range 1.8 KT5 K. At higher temperature (5 K<T20 K), the inelastic scattering time obeys the expression
i
T
–2, due to electronphonon scattering. 相似文献
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We deposited high-quality TiO(2) films by an oxygen-radical beam-assisted evaporation (RBE) method at a lower substrate temperature (Ts) than that for a TiO(2) film deposited by conventional thermal evaporation (TE) with neutral-oxygen gas. The films were then evaluated in terms of refractive index, shift of wavelength of a peak in the reflection curve, and absorption coefficient. The TiO(2) films deposited by RBE at Ts < 473 K showed higher refractive indices, were more compact, and had lower absorption coefficients than the film deposited by TE at Ts = 473 K. 相似文献
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Ji Y Lin KC Zheng H Liu CC Dudik L Zhu J Burda C 《ACS applied materials & interfaces》2010,2(11):3075-3082
Transparent photocatalytic surfaces are of ever increasing importance for many applications on self-cleaning windows and tiles in everyday applications. Here, we report the formation and photocatalytic testing of a quasi-transparent thin and nanoporous titania films deposited on glass plates. Sputtered Ti thin films were anodized in fluoride-ion-containing neutral electrolytes to form optically semitransparent nanoporous films, which transformed to be completely transparent after thermal annealing. The nanoporous films were studied at different stages, such as before and after anodization, as well as after thermal annealing using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis and Raman spectroscopy. It was observed that anodization at 20 V of high-temperature deposited titanium films resulted in regular nanopore films with pore diameters of 30 nm. Structural investigations on the transparent nanopore arrays reveal the presence of anatase phase TiO(2) even after annealing at 500 °C, which was confirmed by XRD and Raman spectroscopy measurements. The solar-light induced photocatalytic decomposition of stearic acid and photoconductivity characteristics of these nanoporous thin films are also presented. 相似文献
7.
《Nanostructured Materials》1992,1(5):419-425
Nanostructured TiO2 with an average grain size of 40 nm was synthesized by the gas condensation technique followed by consolidation and sintering. Pellets of 15 mm diameter and 0.5 mm in thickness were deformed plastically by a gas pressure forming technique. Gas ressures were varied between 100 and 250 kPa, resulting in stresses in the range of 2 to 20 MPa; deformation temperatures varied from 700 to 800°C. After deformation with strains ϵ up to 0.1 the samples did not show any evidence of crackformation. The total deformation at the center of the sample disk, i.e. the apex height, was larger than 2 mm and strain rates were as large as 4 x 10−6 s−1. These experiments show for the first time that nanostructured ceramics can be deformed plastically under tensile stresses below half the melting point. Although the total strain is still small, larger deformation and net shape forming should be possible by this technique, enabling technological applications of nanostructured ceramics. 相似文献
8.
Effects of mineral tourmaline particles on the photocatalytic activity of TiO2 thin films 总被引:1,自引:0,他引:1
Titania composite thin films (T/TiO2) containing tourmaline particles were prepared by a sol-gel method, using alkoxide solutions as precursor. The tourmaline particles and thin films were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and so on. The effects of tourmaline on the photocatalytic activity of TiO2 were measured with methyl orange as an objective photodegradation substance. The results showed that the photocatalytic degradation of methyl orange conformed to the first-order kinetic equation and the composite thin films had better photocatalytic activity due to the cooperation of polarity and the far infrared emission of tourmaline. The T/TiO2 thin films including 0.5 wt% tourmaline exhibited better photocatalytic activity when heat-treated at 250 degrees C for 3 h, than pure TiO2 thin films under the ultraviolet irradiation. 相似文献
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Tianfa Wen Jianping Gao Juyun Shen Zhongshen Zhou 《Journal of Materials Science》2001,36(24):5923-5926
Titanium dioxide (TiO2) thin films have been prepared on microscope slide by the sol-gel process. The preparation of covering solution is investigated with the method of orthogonal experimental design, and the heat treatment temperature and time, which influenced on the films properties are discussed. And the TiO2 thin films had been studied by the means of differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). 相似文献
15.
M. Fallet S. Permpoon J. L. Deschanvres M. Langlet 《Journal of Materials Science》2006,41(10):2915-2927
Sol-gel TiO2 films were deposited from various sols and heat-treated at different temperatures. Fourier transform infrared spectroscopy,
ellipsometry, X-ray diffraction, and scanning electron microscopy methods have been used to study physico-structural properties
of the films. These properties are discussed with respect to the experimental parameters. It is shown that, depending on sol
formulations and annealing temperatures, a large range of crystallite size, crystallization degree, film porosity, and surface
morphology can be covered. The photocatalytic properties of the films have been studied in relation to their physico-structural
properties through the photodecomposition of malic acid. This study shows that the photocatalytic activity undergoes a complex
dependence on the physico-structural properties. 相似文献
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An organic-free sol-gel method was developed to synthesize crack-free, high surface roughness and visible-light-active C-N-codoped TiO(2) films. These films were subsequently evaluated for its photodegradation efficient using stearic acid as the model pollutant compound. The current approach avoids the use of hazardous organic solvents and employs carbon black as the carbon source as well as a template to increase the surface roughness. The presence of carbon and nitrogen species in TiO(2) was studied and discussed. The concentrations of carbon and nitrogen dopants in the TiO(2) films were affected by calcination temperature and the concentration of carbon black. Optimal visible light photocatalytic activity was observed for C-N-codoped TiO(2) film at 10.0 wt.% C, which was more than double that of the N-doped TiO(2) film. The enhancement in visible light photocatalytic activities of the C-N-codoped TiO(2) films was attributed to the synergistic effects of carbon and nitrogen dopants, and high surface roughness of the prepared films. 相似文献
19.
A transparent, high purity titanium dioxide thin film composed of densely packed nanometer sized grains has been successfully
deposited on a glass substrate at 30°C from an aqueous solution of TiO2-HF with the addition of boric acid as a scavenger by liquid phase deposition technique. From X-ray diffraction measurement,
the deposited film was found to be amorphous and turns crystalline at 500°C. The deposited film showed excellent adherence
to the substrate and was characterized by homogeneous flat surface. TiO2 thin films can be used as a photocatalyst to clean up organohalides, a class of compound in pesticides that pollute the ground
water. Photocatalytic degradation experiments show that indanthrene golden orange dye undergoes degradation efficiently in
presence of TiO2 thin films by exposing its aqueous solution to ultraviolet light. The suitable surface structure and porosity increases the
photocatalytic activity. It was also observed that hemin doped TiO2 thin films break up organohalides at a surprisingly high rate under visible light. 相似文献
20.
Pang Xiaoling Feng Qingge Qiu Taoyu Chen Kao Yu Xin Li Xiang Liu Nai 《Journal of Materials Science: Materials in Electronics》2021,32(15):20327-20341
Journal of Materials Science: Materials in Electronics - Defects (oxygen vacancy and Ti3+) play crucial roles in determining band structure, light absorption, and catalytic activity of TiO2.... 相似文献