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1.
ABSTRACTTiO2, ZnO and ZnO/TiO2 thin films have been prepared by radio frequency magnetron sputtering method under different temperatures. Their photo catalytic activities have been investigated. The structural of the thin films were characterized by X-ray diffraction and Raman spectroscopy. The photo catalytic activities of TiO2 and ZnO/TiO2 samples were evaluated by the photo decomposition of methylene blue. We note that the structural proprieties of the thin films showed a perfect crystallization along the (002) for ZnO, Rutile (110) for TiO2 and Anatase (101) for TiO2. The experimental results show that the bilayer ZnO/TiO2 were the most efficient photo catalysts compared to the layer of TiO2. This increased catalytic effect can attributed to the interface between the ZnO layer and the TiO2 one, which modify significantly the chemical potential of the bilayer. 相似文献
2.
The sol-gel route has been applied to obtain ZnO-TiO2 thin films. For comparison, pure TiO2 and ZnO films are also prepared from the corresponding solutions. The films are deposited by a spin-coated method on silicon and glass substrates. Their structural and vibrational properties have been studied as a function of the annealing temperatures (400-750 °C). Pure ZnO films crystallize in a wurtzite modification at a relatively low temperature of 400 °C, whereas the mixed oxide films show predominantly amorphous structure at this temperature. XRD analysis shows that by increasing the annealing temperatures, the sol-gel Zn/Ti oxide films reveal a certain degree of crystallization and their structures are found to be mixtures of wurtzite ZnO, Zn2TiO4, anatase TiO2 and amorphous fraction. The XRD analysis presumes that Zn2TiO4 becomes a favored phase at the highest annealing temperature of 750 °C. The obtained thin films are uniform with no visual defects. The optical properties of ZnO-TiO2 films have been compared with those of single component films (ZnO and TiO2). The mixed oxide films present a high transparency with a slight decrease by increasing the annealing temperature. 相似文献
3.
G. Yildirim S. Bal M. Gulen A. Varilci E. Budak M. Akdogan 《Crystal Research and Technology》2012,47(2):195-201
This study deals with the role of the different substrates on the microstructural, optical and electronical properties of TiO2 thin films produced by conventional direct current (DC) magnetron sputtering in a mixture of pure argon and oxygen using a Ti metal target with the aid of X–ray diffractometer (XRD), ultra violet spectrometer (UV–vis) and atomic force microscopy (AFM) measurements. Transparent TiO2 thin films are deposited on Soda lime glass, MgO(100), quartz and sitall substrates. Phase purity, surface morphology, optical and photocatalytic properties of the films are compared with each other. It is found that the amplitude of interference oscillation of the films is in a range of 77‐89%. The transmittance of the film deposited on Soda lime glass is the smallest while the film produced on MgO(100) substrate obtains the maximum transmittance value. The refractive index and optical band gap of the TiO2 thin films are also inferred from the transmittance spectra. The results show that the film deposited on Soda lime glass has the better optical property while the film produced on MgO(100) substrate exhibits much better photoactivity than the other films because of the large optical energy band gap. As for the XRD results, the film prepared on MgO(100) substrate contains the anatase phase only; on the other hand, the other films contain both anatase and rutile phases. Furthermore, AFM images show that the regular structures are observed on the surface of all the films studied. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
4.
X. H. Xu M. Wang Y. Hou S.R. Zhao H. Wang D. Wang S.X. Shang 《Crystal Research and Technology》2002,37(5):431-439
TiO2 thin films, were deposited on Si(100) and Si(111) substrates by metalorganic chemical vapor deposition at 500 °C, and have been annealed for 2 min, 30 min and 10 hours at the temperature from 600 °C to 900 °C, in oxygen and air flow, respectively. XRD and atomic force microscopy characterized the structural properties and surface morphologies of the films. As‐deposited films show anatase polycrystalline structure with a surface morphology of regular rectangled grains with distinct boundaries. Rutile phase formed for films annealed above 600 °C, and pure rutile polycrystalline films with (110) orientation can be obtained after annealing under adequate conditions. Rutile annealed films exhibit a surface morphology of equiaxed grains without distinct boundaries. The effects of substrate orientation, annealing time and atmosphere on the structure and surface morphology of films have also been studied. Capacitance‐Voltage measurements have been performed for films deposited on Si(100) before and after annealing. The dielectric properties of TiO2 films were greatly improved by thermal annealing above 600 °C in oxygen. 相似文献
5.
Hongfu Sun Chengyu Wang Shihong Pang Xiping Li Ying Tao Huajuan Tang Ming Liu 《Journal of Non》2008,354(12-13):1440-1443
Nanometer semiconductor titanium dioxide thin films have excellent properties of photocatalysitic degeneration. The glass coated TiO2 films is called self-cleaning glass. In this paper, chemical vapor deposition (CVD) method is employed to deposit TiO2 films on glass. The effect of spacing between nozzle and glass and the effect of substrate temperature on deposition rate are studied. The crystalline structure at different deposition temperatures is analyzed by XRD and anatase was found. And the microstructure of the TiO2 films is also determined by SEM. It shows that the size of crystal grain increases with the temperature. 相似文献
6.
Optical properties of spray deposited antimony (Sb) doped tin oxide (SnO2) thin films, prepared from SnCl2 precursor, have been studied as a function of antimony doping concentration. The doping concentration was varied from 0‐4 wt.% of Sb. All the films were deposited on microscope glass slides at the optimized substrate temperature of 400 °C. The films are polycrystalline in nature with tetragonal crystal structure. The doped films are degenerate and n‐type conducting. The sheet resistance of tin oxide films was found to decrease from 38.22 Ω/□ for undoped films to 2.17 Ω/□ for antimony doped films. The lowest sheet resistance was achieved for 2 wt.% of Sb doping. To the best of our knowledge, this sheet resistance value is the lowest reported so far, for Sb doped films prepared from SnCl2 precursor. The transmittance and reflectance spectra for the as‐deposited films were recorded in the wavelength range of 300 to 2500 nm. The transmittance of the films was observed to increase from 42 % to 55 % (at 800 nm) on initial addition of Sb and then it is decreased for higher level of antimony doping. This paper investigates the variation of optical and electrical properties of the as‐deposited films with Sb doping. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
SnO2 films have been deposited on Y-stabilized ZrO2 (YSZ) (1 0 0) substrates at different substrate temperatures (500–800 °C) by metalorganic chemical vapor deposition (MOCVD). Structural, electrical and optical properties of the films have been investigated. The films deposited at 500 and 600 °C are epitaxial SnO2 films with orthorhombic columbite structure, and the HRTEM analysis shows a clear epitaxial relationship of columbite SnO2(1 0 0)||YSZ(1 0 0). The films deposited at 700 and 800 °C have mixed-phase structures of rutile and columbite SnO2. The carrier concentration of the films is in the range from 1.15×1019 to 2.68×1019 cm−3, and the resistivity is from 2.48×10−2 to 1.16×10−2 Ω cm. The absolute average transmittance of the films in the visible range exceeds 90%. The band gap of the obtained SnO2 films is about 3.75–3.87 eV. 相似文献
8.
J. Siva Kumar K. V. Styatanarayana Rao U. V. Subba Rao 《Crystal Research and Technology》1990,25(6):727-732
Thin films of various thicknesses in the MIM structure have been prepared from the powder of SnO2/Sb2O3 mixed sample by the thermal evaporation technique in a vacuum of 10−5 Torr. Dielectric properties of SnO2/Sb2O3 mixed thin films have been studied with temperature starting from LNT to RT and above RT and frequency ranging from 100 Hz to 16 kHz. The activation energy for the migration of charge carriers in SnO2/Sb2O3 mixed thin films has been calculated and it is found to be 0.23 eV. The results thus obtained on dielectric properties of SnO2/Sb2O3 mixed thin films are presented and discussed. 相似文献
9.
S. Sebnem Cetin S. Corekci M. Cakmak S. Ozcelik 《Crystal Research and Technology》2011,46(11):1207-1214
Titanium dioxide (TiO2) thin film was deposited on n‐Si (100) substrate by reactive DC magnetron sputtering system at 250 °C temperature. The deposited film was thermally treated for 3 h in the range of 400‐1000 °C by conventional thermal annealing (CTA) in air atmosphere. The effects of the annealing temperature on the structural and morphological properties of the films were investigated by X‐ray diffraction (XRD) and atomic force microscopy (AFM), respectively. XRD measurements show that the rutile phase is the dominant crystalline phase for the film annealed at 800 °C. According to AFM results, the increased grain sizes indicate that the annealing improves the crystalline quality of the TiO2 film. In addition, the formation of the interfacial SiO2 layer between TiO2 film and Si substrate was evaluated by the transmittance spectra obtained with FTIR spectrometer. The electronic band transitions of as‐deposited and annealed films were also studied by using photoluminescence (PL) spectroscopy at room temperature. The results show that the dislocation density and microstrain in the film were decreased by increasing annealing temperature for both anatase and rutile phases. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
10.
《Journal of Non》2006,352(30-31):3315-3319
CdS nanoparticles have been prepared via a colloidal route using 3-mercatopropyltrimethoxysilane as a capping agent. The stability of the particles in solution and embedded in TiO2 matrices has been followed by optical absorption. Both the size and the size distribution of the particles are well controlled, thus allowing a tunable emission. Raman and photoluminescence spectroscopies have been used to characterize colloidal CdS, TiO2:CdS solutions and thin films deposited on soda-lime slides. The Z-scan technique has been used to measure the non-linear refractive indices of the solutions and the non-linear absorption coefficients of the thin films. 相似文献
11.
Glasses for architecture must have many functions in addition to their transparency. For example, the glasses with the functions, of self-cleaning, light control, UV reduction, anti-bacterial, energy conversion, and so on, will be used in buildings in the near future. This paper reviews some results on multifunctional photoactive glasses based on multi-layer coatings containing TiO2 film and other functional coatings developed by us recently. The self-cleaning of glasses can be realized by coating the photoinduced super-hydrophilic nanoporous thin films based on TiO2 photocatalysts via sol–gel route. A new method to enhance the photocatalytic activity of TiO2 thin films direct coated on soda-lime glass was developed by treating the films in acidic solutions. The films also have good photoinduced anti-bacterial properties. The doping of a small amount of silver into the TiO2 porous film can enhance its anti-bacteria effect without UV light irradiation. The TiO2 thin films by appropriate heat-treatment can operate as self-cleaning glass in the visible light region. The UV reduction self-cleaning glasses are prepared by magnetron sputtering two layers of TiO2–CeO2 and TiO2 thin films on soda-lime glasses. The TiO2–CeO2 thin films can cut all of UV light through adjusting the ratio of TiO2 and CeO2. The TiO2/TiN/TiO2 type multi-layer coated on glass substrate can act as low-E self-cleaning glass. The potential water-repellent coating based on TiO2 is discussed finally. 相似文献
12.
J. Siva Kumar U. V. Subba Rao K. V. Satyanarayana Rao K. Narasimha Reddy 《Crystal Research and Technology》1991,26(1):103-108
Thin films of various thicknesses in the MIM structure have been prepared from the the powders of SnO2, Sb2O3 and (SnO2 + Sb2O3) of high purity by the thermal evaporation technique in a vacuum of 10−5 Torr. Dielectric properties of SnO2, Sb2O3, and their mixed thin films have been studied with ac and dc electric fields and frequency. Capacitance and loss tangent are almost independent on dc voltage upto 1.0 V for SnO2, 10.0 V for Sb2O3 and 2.5 V for mixed films. These capacitors become unstable at 1.0 V for SnO2 films and 2.5 V for mixed films. For higher film thicknesses the decay in these films starts at higher voltages. Capacitance and loss tangent increases with applied ac voltage in SnO2, Sb2O3, and their mixed films. A comparison of the capacitance values of SnO2, Sb2O3, and their mixed films showed that the capacitance values are less in Sb2O3 as compared to SnO2 films. In mixed films the capacitance is greater than the constituent films. These studies have shown that Sb2O3 films are found to be more stable compared to SnO2 and their mixed films for ac and dc voltages. The results thus obtained on SnO2, Sb2O3, and their films are presented and discussed. 相似文献
13.
J. Grzechulska M. Hamerski A. W. Morawski 《Molecular Crystals and Liquid Crystals》2013,570(2):243-248
Abstract In this work we prepared the stable photocatalyst by the incorporation of lithium into TiO2 host. Lithium hydroxide was used as the modifier. Titanium host material was in two forms: commercial titanium dioxide (anatase. Police Chemical Factory, Poland) and titanium slurry that was slightly crystallized. The prepared materials have been characterized by XRD. FTIR and UV-Vis/DR methods. The XRD analysis showed that the main component of these samples was lithium titanate—Li2TiO3. The photocatalytic activity of prepared materials was tested in the photocatalytic reactions of oil and phenol decomposition in water. It was found that both oil and phenol undergo the photocatalytic decomposition over lithium-TiO2 and the activity of these materials was higher in comparison with that of pure anatase host. 相似文献
14.
TiO2 thin films were prepared by DC reactive magnetron sputtering on heated Si, quartz and glass substrates using O2 and water vapor as reactive gases. The percentage of anatase and rutile as well as the grain size strongly depend on the deposition conditions, as revealed by X-ray diffraction patterns. The films deposited on Si substrates are pure rutile, while a mixed anatase/rutile structure occurs in the films deposited on glass and quartz substrates. Smaller grain rutile and anatase films were prepared in a water vapor atmosphere, in contrast to the films grown in oxygen. The former choice considerably increases the sensing properties of titanium dioxide films. The gas sensitivity was investigated for some reducing gases (methane, acetone, ethanol and liquefied petroleum gas) and the optimum operating temperatures were found. 相似文献
15.
Undoped and 5%(Mn, In)-doped SnO2 thin films were deposited on Si(1 0 0) and Al2O3 (R-cut) by RF magnetron sputtering at different deposition power, sputtering gas mixture and substrate temperature. X-ray reflectivity was used to determine the films thickness (10–130 nm) and roughness (~1 nm). The combination of X-ray diffraction and Mössbauer techniques evidenced the presence of Sn4+ in an amorphous environment, for as-grown films obtained at low power and temperature, and the formation of crystalline SnO2 for annealed films. As the deposition power, substrate temperature or O2 proportion are increased, SnO2 nanocrystals are formed. Epitaxial SnO2 films are obtained on Al2O3 at 550 °C. The amorphous films are quite uniform but a more columnar growth is detected for increasing deposition power. No secondary phases or segregation of dopants were detected. 相似文献
16.
Titanium dioxide (TiO2) coatings have been long considered as biocompatible interfaces to promote the physico-chemical bonding between the bone tissues and implant material (e.g., titanium and stainless steel). Monodispersed TiO2 (anatase, the low temperature polymorph of TiO2) microspheres, produced in the form of colloidal precipitates, were deposited on different substrates and apatite formation was induced on the resulted surface by immersing the coated substrates in simulated body fluid solution. Analytical and microstructural investigations, conducted by X-ray diffraction, energy depressive X-ray spectroscopy and scanning electron microscopy techniques, showed considerable higher rates of apatite formation, in vitro, on the anatase microspheres compared to the sol-gel-derived thin films of the same oxide. We concluded that the particular surface morphology of the packed TiO2 microspheres, promotes a faster apatite formation in vitro. 相似文献
17.
Bi3.15Nd0.85Ti2.8-xZr0.2MnxO12 (BNTZM) thin films with various Mn content (x = 0, 0.005, 0.01, 0.03, and 0.05) have been prepared on Pt/Ti/SiO2/Si (100) substrates by a chemical solution deposition (CSD) technique. The crystal structures of BNTZM thin film have been analyzed by X-ray diffraction (XRD). The dependence of Mn contents on the ferroelectric, dielectric properties, and leakage current of these BNTZM films have been thoroughly investigated. The XRD analysis demonstrated that all the BNTZM thin films were of typical bismuth-layer-structured ferroelectrics (BLSF) polycrystalline structure and exhibited a highly preferred (117) orientation. Among these BNTZM films, the BNTZM thin film with Mn content equal to 0.01 exhibits the maximum remnant polarization (2Pr) of 48μC/cm2 and a low coercive field (2Ec) of 177 kV/cm. In addition, the BNTZM thin film with x = 0.01 (Mn) showed a fatigue-free behavior up to 1 × 1010 read/write cycles. 相似文献
18.
Xihong Hao Jiwei Zhai Zhenxing Yue Jing Zhou Jichun Yang Shengli An 《Journal of Crystal Growth》2011,314(1):151-156
In the present work, the effects of oxide buffer layers, such as ZrO2, CeO2 and TiO2, on the microstructure and electrical properties of (Pb0.97La0.02)(Zr0.87Sn0.10Ti0.03)O3 (PLZST 2/87/10/3) antiferroelectric (AFE) thin films were investigated systematically. X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) pictures illustrated that the crystalline orientation and surface microstructure of PLZST 2/87/10/3 AFE thin films had a close relation with these oxide buffer layers. As a result, the final electrical properties of AFE films were tuned by these buffer layers. Electrical measurements result showed that the dielectric properties, polarization characteristic and current–field curves of AFE thin films could be tailored by selecting a proper oxide buffer layer. 相似文献
19.
Hydrogenated carbon nitride (a-CN:H) films were deposited on n-type (1 0 0) silicon substrates making use of direct current radio frequency plasma enhanced chemical vapor deposition (DC-RF-PECVD), using a gas mixture of CH4 and N2 as the source gas in range of N2/CH4 flow ratio from 1/3 to 3/1 (sccm). The deposition rate, composition and bonding structure of the a-CN:H films were characterized by means of X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectrometry (FTIR). The mechanical properties of the deposited films were evaluated using nano-indentation test. It was found that the parameter for the DC-RF-PECVD process had significant effects on the growth rate, structure and properties of the deposited films. The deposition rate of the films decreased clearly, while the N/C ratio in the films increased with increasing N2/CH4 flow ratio. CN radicals were remarkably formed in the deposited films at different N2/CH4 flow ratio, and their contents are related to the nitrogen concentrations in the deposited films. Moreover, the hardness and Young’s modulus of the a-CN:H films sharply increased at first with increasing N2/CH4 flow ratio, then dramatically decreased with further increase of the N2/CH4 flow ratio, and the a-CN:H film deposited at 1/1 had the maximum hardness and Young’s modulus. In addition, the structural transformation from sp3-like to sp2-like carbon-nitrogen network in the deposited films also was revealed. 相似文献
20.
Tin oxide (SnO2) thin films were deposited on UV fused silica (UVFS) substrates using filtered vacuum arc deposition (FVAD). During deposition, the substrates were at room temperature (RT). As-deposited films were annealed at 400 and 600 °C in Ar for 30 min. The film structure, composition, and surface morphology were determined as function of the annealing temperature using X-ray diffraction (XRD), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The XRD patterns of the SnO2 thin films deposited on substrates at RT indicated that the films were amorphous, however, after the annealing the film structure became polycrystalline. The grain size of the annealed films, obtained from the XRD analysis, increased with the annealing temperature, and it was in the range 8-34 nm. The AFM analysis of the surface revealed an increase in the film surface average grain size from 15 nm to 46 nm, and the surface roughness from 0.2 to 1.8 nm, as function of the annealing temperature. The average optical transmission of the films in the visible spectrum was >80%, and increased by the annealing ∼10%. The films’ optical constants in the 250-989 nm wavelength range were determined by variable angle spectroscopic ellipsometry (VASE). The refractive indexes of as-deposited and annealed films were in the range 1.83-2.23 and 1.85-2.3, respectively. The extinction coefficients, k(λ), of as-deposited and annealed films were in the range same range ∼0-0.5. The optical energy band gap (Eg), as determined by the dependence of the absorption coefficient on the photon energy at short wavelengths, increased with the annealing temperature from 3.90 to 4.35 eV. The lowest electrical resistivity of the as-deposited tin oxide films was 7.8 × 10−3 Ω cm, however, film annealing resulted in highly resistive films. 相似文献