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1.
O. Van Overschelde 《Applied Surface Science》2007,253(19):7890-7894
Thin films of TiO2 are deposited by magnetron sputtering on glass substrate and are irradiated by UV radiation using a KrF excimer laser (248 nm). These thin films are patterned with a razor blade placed on the way of the radiation just in front of the TiO2 thin film. Just near the edge of the razor blade on the thin film, diffraction lines are observed, resulting in the ablation of the film. These patterns are characterized by optical microscopy, mechanical profilometry. Diffraction up to the 35th order is observed. The results are shown to be compatible with a model in which electronic excitation plays the major role. 相似文献
2.
ZnO thin films were prepared on soda-lime glass from a single spin-coating deposition of a sol-gel prepared with anhydrous zinc acetate [Zn(C2H3O2)2], monoethanolamine [H2NC2H4OH] and isopropanol. The deposited films were dried at 50 and 300 °C. X-ray analysis showed that the films were amorphous. Laser annealing was performed using an excimer laser. The laser pulse repetition rate was 25 Hz with a pulse energy of 5.9 mJ, giving a fluence of 225 mJ cm−2 on the ZnO film. Typically, five laser pulses per unit area of the film were used. After laser processing, the hexagonal wurtzite phase of zinc oxide was observed from X-ray diffraction pattern analysis. The thin films had a transparency of greater than 70% in the visible region. The optical band-gap energy was 3.454 eV. Scanning electron microscopy and profilometry analysis highlighted the change in morphology that occurred as a result of laser processing. This comparative study shows that our sol-gel processing route differs significantly from ZnO sol-gel films prepared by conventional furnace annealing which requires temperatures above 450 °C for the formation of crystalline ZnO. 相似文献
3.
TiO2 and ZrO2 nanocrystals were successfully synthesized and deposited onto wool fibers using the sol-gel technique at low temperature. The photocatalytic activities of TiO2-coated and ZrO2-coated wool fibers were measured by studying photodegradation of methylene blue and eosin yellowish dyes. The initial and the treated samples were characterized by several techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and X-ray diffraction. The TEM study shows dispersed particles with 10-30 nm in size for TiO2-coated and 20-40 nm in size for ZrO2-coated samples on the fiber surface. Comparison of the photocatalytic activity of the coated samples reveals superiority of TiO2 modified sample with respect to that of ZrO2 for degradation of both dyes. Our observations indicate that by applying this technique to the fabrics, self-cleaning materials could be designed for practical application. 相似文献
4.
Aytaç Gültekin Gamze Karanfil Faruk Özel Mahmut Kuş Ridvan Say Savaş Sönmezoğlu 《Journal of Physics and Chemistry of Solids》2014
In the present study, pure and gold nanoparticle (Au NP)-doped titanium dioxide (TiO2) and cadmium oxide (CdO) thin film were prepared by the sol–gel method, and the effect of Au NP doping on the optical, structural and morphological properties of these thin films was investigated. The prepared thin films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet–visible–near infrared (UV–Vis–NIR) spectra. While the optical band increases from 3.62 to 3.73 for TiO2 thin films, it decreases from 2.20 to 1.55 for CdO thin films with increasing Au doping concentration. Analysis of XRD indicates that the intensities of peaks of the crystalline phase have increased with the increasing Au NP concentrations in all thin films. SEM images demonstrate that the surface morphologies of the samples were affected by the incorporation of Au NPs. Consequently, the most significant results of the present study are that the Au NPs can be used to modify the optical, structural and morphological properties of TiO2 and CdO thin films. 相似文献
5.
Porous TiO2 films were deposited on SiO2 pre-coated glass-slides by sol-gel method using octadecylamine (ODA) as template. The amount of ODA in the sol played an important role on the physicochemical properties and photocatalytic performance of the TiO2 films. The films prepared at different conditions were all composed of anatase titanium dioxide crystals, and TiO2 crystalline size got larger with increasing ODA amount. The maximum specific surface area of 41.5 m2/g was obtained for TiO2 powders prepared from titanium sol containing 2.0 g ODA. Methyl orange degradation rate was enhanced along with increasing ODA amount and reached the maximal value at 2.0 g addition of ODA. After 40 min of UV-light irradiation, methyl orange degradation rate reached 30.5% on the porous film, which was about 10% higher than that on the smooth film. Porous TiO2 film showed almost constant activity with slight decrease from 30.5% to 28.5% after 4 times of recycles. 相似文献
6.
The anatase-TiO2 transparent films, containing 3 mol% of Si and P elements (as dopants), were synthesized using a process combining the sol-gel method and spin-coating technique. Effects of relative ratio of dopants and calcination temperature on phase transformation, grain growth, surface morphology, light transmittance, band-gap energy and photocatalytic activity of the P/Si-TiO2 films were examined and their results were compared with those of the undoped-TiO2 and Si-TiO2 films. The P/Si-TiO2 films calcined at temperature between 600 and 900 °C adhered strongly to the surface of fused-silica substrate and were composed of anatase-TiO2 monophase. The photocatalytic activities of the films were measured and represented using a characteristic time constant (τ) for the methylene blue (MB) photodegradation. The small τ stands for high photocatalytic ability of the film. The P/Si-TiO2 film, containing equalmolar Si and P dopants, calcined at 800 °C gave the best performance in photocatalysis; this film had τ=5.7 h and decomposed about 90 mole% of MB in the water after 12 h of the 365-nm UV light irradiation. 相似文献
7.
Titanium dioxide thin films have been prepared from tetrabutyl-orthotitanate solution and methanol as a solvent by sol-gel dip coating technique. TiO2 thin films prepared using a sol-gel process have been analyzed for different annealing temperatures. Structural properties in terms of crystal structure were investigated by Raman spectroscopy. The surface morphology and composition of the films were investigated by atomic force microscopy (AFM). The optical transmittance and reflectance spectra of TiO2 thin films deposited on silicon substrate were also determined. Spectroscopic ellipsometry study was used to determine the annealing temperature effect on the optical properties and the optical gap of the TiO2 thin films. The results show that the TiO2 thin films crystallize in anatase phase between 400 and 800 °C, and into the anatase-rutile phase at 1000 °C, and further into the rutile phase at 1200 °C. We have found that the films consist of titanium dioxide nano-crystals. The AFM surface morphology results indicate that the particle size increases from 5 to 41 nm by increasing the annealing temperature. The TiO2 thin films have high transparency in the visible range. For annealing temperatures between 1000 and 1400 °C, the transmittance of the films was reduced significantly in the wavelength range of 300-800 nm due to the change of crystallite phase and composition in the films. We have demonstrated as well the decrease of the optical band gap with the increase of the annealing temperature. 相似文献
8.
In this work a novel method for synthesising TiN coatings is reported. A high-power diode laser at different powers and traverse speeds was applied to a mild steel substrate, coated with a slurry of titania sol-gel, urea and graphite. The reaction chemical thermodynamics was investigated to estimate the compositions, temperature range, and the required reaction enthalpy for producing TiN. A one-dimensional heat transfer model was used to optimise the processing parameters. Surface morphology and microstructure of the deposited coatings and substrate surface layers were examined using optical microscopy, scanning electron microscope, and field emission gun scanning electron microscope which reveals deposition of very thin layer about 0.3 μm of pure TiN and the presence of sub-micron crystalline structure of TiN forming a metal matrix composite inter-layer with the substrate below the film which suggest a good metallurgically bonding with the substrate. Chemical composition was determined by energy dispersive X-ray analysis. The phases were identified by X-ray diffraction which confirms the synthesis of TiN film for all the samples. Results of nano-hardness measurements revealed a hardness value of the order of 22-27 GPa. 相似文献
9.
Titanium dioxide thin films have been deposited by reactive magnetron sputtering on glass substrate and subsequently irradiated by UV radiation using a KrF excimer laser. In this work, we have study the influence of the laser fluence (F) ranging between 0.05 and 0.40 mJ/cm2 on the constitution and microstructure of the deposited films. Irradiated thin films are characterized by profilometry, scanning electron microscopy and X-ray diffraction. As deposited films are amorphous, while irradiated films present an anatase structure. The crystallinity of the films strongly varies as a function of F with maximum for F = 0.125 J/cm2. In addition to the modification of their constitution, the irradiated areas present a strongly modified microstructure with appearance of nanoscale features. The physico-chemical mechanisms of these structural modifications are discussed based on the theory of nucleation. 相似文献
10.
Thin titanium dioxide films are deposited on glass substrates by magnetron sputter deposition. They are irradiated in air, by means of a KrF excimer laser. The ablation rate is measured as a function of the laser fluence per pulse, F, and of the number of pulses, N. Above a fluence threshold, the films are partially ablated. The ablated thickness does not vary linearly with N. This is the signature of a negative feedback between the film thickness and the ablation rate. The origin of this negative feedback is shown to be due to either thermal or electronic effects, or both. At high F, the film detachs from the substrate. 相似文献
11.
Previous studies suggest that granular interfaces induce a natural and persistent super-hydrophilicity in TiO2-SiO2 composite thin films deposited by sol-gel route. This effect enables to consider self-cleaning applications that do not require a permanent UV exposure, whereas such a permanent exposure is necessary for pure TiO2 films. In this study, TiO2-SiO2 composite thin films have been deposited from a TiO2 anatase crystalline suspension and different SiO2 polymeric sols. Wettability studies show that a suitable control of the TiO2-SiO2 mixed sol formulations noticeably enhances persistence of the natural super-hydrophilicity in composite films. It is shown that, beside granular interface effects, modifications in the composite film morphologies can noticeably influence wettability properties. 相似文献
12.
C. Sudakar P. Kharel R. Suryanarayanan J.S. Thakur V.M. Naik R. Naik G. Lawes 《Journal of magnetism and magnetic materials》2008
Thin films of pure TiO2 have been prepared using both spin-coating and sputter-deposition techniques on sapphire and quartz substrates. The structural characteristics of the films have been investigated in detail using Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM). When annealed in vacuum, all films demonstrate room temperature ferromagnetism, while the air-annealed samples show much smaller, often negligible, magnetic moments. The magnetization of the vacuum-annealed sputtered samples depends on film thickness, with the volume magnetization decreasing monotonically with increasing thickness. Furthermore, the magnetization per unit area also decreases slightly with increasing film thickness. These results suggest that ferromagnetism in the vacuum-annealed TiO2 films is mediated by surface defects or interfacial effects, but does not arise from stoichiometric crystalline TiO2. 相似文献
13.
The La2Hf2O7 films have been deposited on Si (1 0 0) substrate by using pulsed laser deposition (PLD) method. X-ray diffraction (XRD) demonstrates that the as-grown film is amorphous and crystallizes after 1000 °C annealing. The interface structure is systematically studied by Synchrotron X-ray reflectivity (XRR), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). Silicide, silicate and SiOx formations from interfacial reaction are observed on the surface of the Si substrate in the as-grown film. The impact of silicide formation on the electrical properties is revealed by capacitance-voltage (C-V) measurements. By post-deposition annealing (PDA), silicide can be effectively eliminated and C-V property is obviously improved. 相似文献
14.
The Hg-doped and undoped nano-crystalline TiO2 films on ITO glass substrates surface and polycrystalline powders were prepared by sol-gel dip coating technique. The crystal structure and surface morphology of TiO2 were characterized by means of X-ray diffractometer (XRD), atomic force microscope (AFM), spectrophotometer, Fourier-transform infrared (FTIR), and spectroscopic ellipsometry (SE). The results indicated that the powder of TiO2, doped with 5% Hg in room temperature was only composed of the anatase phase whereas in the undoped powder exhibits an amorphous phase were present. After heat treatments of thin films, titanium oxide starts to crystallize at the annealing temperature 400 °C. The average crystallite size of the undoped TiO2 films was about 8.17 nm and was increased with Hg-doping in the TiO2 films. Moreover, the grains distributed more uniform and the surface roughness was greater in the Hg-doped TiO2 films than in the undoped one. Refractive index and porosity were calculated from the measured transmittance spectrum. The values of the index of refraction are in the range (1.95-2.49) and the porosity is in the range (47-2.8). The coefficient of transmission varies from 60 to 90%. SE study was used to determine the annealing temperature effect on the optical properties in the wavelength range from 0.25 to 2 μm and the optical gap of the Hg-doped TiO2 thin films. 相似文献
15.
Marcial Zamora Tessy López Ricardo Gómez Maximiliano Asomoza 《Applied Surface Science》2005,252(3):828-832
The vapor-phase condensation of acetone was studied over sol-gel prepared TiO2 and TiO2-doped with 1 wt.% of Li+ or Rb+. The acetone condensation was catalyzed by basic sites and the obtained products were mesityl oxide (MO), isomesityl oxide (ISMO), mesitylene (M) as well as isophorone (IP) and phorone (P). The TiO2 crystalline structure was characterized by XRD and the basicity of catalysts by means of CO2 chemisorption. The number of basic sites was 0.057 mmol CO2/g for TiO2 and Rb/TiO2 and 0.676 mmol CO2/g for Li/TiO2 catalyst. CO2-TPD showed that the strongest of the basic sites follows the order Rb/TiO2 > TiO2 > Li/TiO2. Activity was found of the same order in the three catalysts. Selectivity patterns shown that MO (70%) was the main product in Li/TiO2 while for TiO2 and Rb/TiO2 comparable amounts of MO (41 and 44%) and M (39 and 39%) were obtained. 相似文献
16.
A novel 6SrO·6BaO·7Al2O3 (S6B6A7) thin film deposited onto soda lime float glass via sol-gel dip coating technique is reported. The morphological and compositional properties of the S6B6A7 thin films have been investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) revealing that the films were composed of S6B6A7 nanoparticles. The optical properties of the S6B6A7 films are affected by sol concentration, film thickness and annealing temperature as revealed by UV-vis transmittance. The transparency of S6B6A7 films improved on increasing annealing temperature up to 450 °C in air. The S6B6A7 films prepared using 2, 5, and 8 (wt.%) sols and annealed at 450 °C exhibit an average transmittance of over ∼91% in wide visible range. 相似文献
17.
It is shown that different highly oriented Pb(Zr0.52,Ti0.48)O3 films can be obtained on Pt/Ti/SiO2/Si substrate using a sol-gel technique. The effects of pyrolysis temperature on the orientation, phase composition and ferroelectric properties of the films are investigated. It is found the ferroelectric hysteresis loops of (1 1 1)-oriented film, (1 1 1) and (1 0 0) mix-oriented film can both be saturated when the external electric field is large enough, whereas the hysteresis loop of (1 0 0)-oriented film is difficult to saturate. The analysis of X-ray diffraction indicated the possibility of different phase composition in different oriented films under large film residual stress. Higher remnant polarization (53 μC/cm2) for (1 0 0)-oriented film can be attributed to its more tetragonal phase composition, which results in that the in-plane domain switching can continuously occur with external electric field increasing. 相似文献
18.
TiO2-doped WO3 thin films were deposited onto fluorine-doped tin oxide coated conducting glass substrates using spray pyrolysis technique at 525 °C. The volume percentage of TiO2 dopant was varied from 13% to 38%. The thin film samples were transparent, uniform and strongly adherent to the substrates. Electrochromical properties of TiO2-doped WO3 thin films were studied with the help of cyclic voltammetry (CV), chronoamperometry (CA) and chronocoulometry (CC) techniques. It has been found that TiO2 doping in WO3 enhances its electrochromic performance. Colouration efficiency becomes almost double and samples exhibit increasingly high reversibility with TiO2 doping concentrations, in the studied range. 相似文献
19.
This work presents the annealing temperature effect on the properties of mercury (Hg)-doped titanium dioxide (TiO2). Thin films and polycrystalline powders have been prepared by sol-gel process. The structure, surface morphology and optical properties, as a function of the annealing temperature, have been studied by atomic force microscopy (AFM), Raman, reflectance and ellipsometric spectroscopies. In order to determine the transformation points, we have analyzed the xerogel-obtained powder by differential scanning calorimetry (DSC). Raman spectroscopy shows the crystalline anatase and rutile phases for the films annealed at 400 °C and 1000 °C respectively. The AFM surface morphology results indicate that the particle size increases from 14 to 57 nm by increasing the annealing temperature. The complex index and the optical band gap (Eg) of the films were determined by the spectroscopic ellipsometry analysis. We have found that the optical band gap decreases by increasing the annealing temperature. 相似文献
20.
Shigeyuki Nakamura Shizutoshi Ando 《Journal of Physics and Chemistry of Solids》2005,66(11):1944-1946
Metal-organic decomposition (MOD) technique has been developed as a low cost thin film CuInS2 preparation method for solar cell application. XRD and Raman spectra measurement revealed that deposited films contain CuInS2. Stoichiometric films with a bandgap of 1.53 eV and an FWHM of 0.45° were obtained from a solution with Cu/In=1.5. 相似文献