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1.
In the present study TiO2 films were deposited by spray pyrolysis method onto ITO covered glass and Si (1 0 0) substrates. The spray solution containing titanium(IV) isopropoxide, acetylacetone and ethanol was sprayed at a substrate temperature of 450 °C employing 1-125 spray pulses (1 s spray and 30 s pause). According to AFM, continuous coverage of ITO and Si substrates with TiO2 layer is formed by 5-10 and below 5 spray pulses, respectively. XPS studies revealed that TiO2 film growth on Si substrate using up to 4 spray pulses follows 2D or layer-by-layer-growth. Above 4 spray pulses, 3D or island growth becomes dominant irrespective of the substrate. Only 50 spray pulses result in TiO2 layer with the thickness more than XPS measurement escape depth as any signal from the substrate could not be detected. TiO2 grain size remains 30 nm on ITO and increases from 10-20 nm to 50-100 nm on Si substrate with the number of spray pulses from 1 to 125. 相似文献
2.
Pure and Au-doped mesostructured SnO2 thin films were successfully prepared by using non-ionic surfactant Brij-58 (polyoxyethylene acyl ether) as organic template and tin tetrachloride and hydrogen tetrachloroaurate(III) trihydrate as inorganic precursor. Thin films were deposited onto the glass substrates at 450 °C by simple spray pyrolysis technique. The novel mesostructured tin oxide thin films with different Au concentration exhibit highly selective response towards CO. The correlation of the Au incorporation in the mesostructure with particular morphology and gas sensing behavior is discussed using scanning electron microscopy (SEM), X-ray diffraction (XRD), BET surface area and transmission electron microscopy (TEM) studies. 相似文献
3.
H.M. Martínez J. Torres M.E. Rodríguez-García L.D. López Carreño 《Physica B: Condensed Matter》2012,407(16):3199-3202
Thin films of molybdenum trioxide (MoO3) were deposited on common glass using the chemical spray pyrolysis technique. A (NH4)6Mo7O244H20 solution 0.1 M was used as the precursor one. The influence of substrate temperature on the crystallographic structure, surface morphology and electrical behavior of MoO3 thin films was studied. MoO3 can exist in two crystalline forms, the thermodynamically stable orthorhombic α-MoO3 and the metastable monoclinic β-MoO3 phase. XRD-spectra showed a growth of α-MoO3 phase percentage as substrate temperature increases from 420 K up to 670 K. Films deposited in the 500–600 K range have a clearly porous surface structure of nanometer order as can be seen in SEM images. Changes up to six magnitude orders were observed in MoO3 thin films electrical resistance when films temperature varied from 100 K up to 500 K. The sensing property of these MoO3 films was also studied. The sensitivity was investigated in the temperature range 160 and 360 K for H2O and CO gases, respectively. Both of them are of reducing nature. In all studied cases sensitivity decreases slowly as film temperature is raised. At room temperature the sensitivity changes from 12 up to 75% depending on substrate temperature. The sensitivity for CO gas was found to be lower than that of H2O. 相似文献
4.
Nanocrystalline SnO2 thin films were deposited by simple and inexpensive chemical route. The films were characterized for their structural, morphological, wettability and electrochemical properties using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy techniques (SEM), transmission electron microscopy (TEM), contact angle measurement, and cyclic voltammetry techniques. The XRD study revealed the deposited films were nanocrystalline with tetragonal rutile structure of SnO2. The FT-IR studies confirmed the formation of SnO2 with the characteristic vibrational mode of Sn-O. The SEM studies showed formation of loosely connected agglomerates with average size of 5-10 nm as observed from TEM studies. The surface wettability showed the hydrophilic nature of SnO2 thin film (water contact angle 9°). The SnO2 showed a maximum specific capacitance of 66 F g−1 in 0.5 Na2SO4 electrolyte at 10 mV s−1 scan rate. 相似文献
5.
Structural, morphological and optical properties of CuAlS2 films deposited by spray pyrolysis method
The structural, morphological and optical properties of CuAlS2 films deposited by spray pyrolysis method have been investigated. CuAlS2 in the form of films is prepared at different deposition conditions by a simple and economical spray pyrolysis method. The structural, surface morphology and optical properties of the films were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and absorbance spectra, respectively. The films were polycrystalline, crystallized in a tetragonal structure, and are preferentially orientated along the (1 1 2) direction. Grain size values, dislocation density, and d% error of CuAlS2 films were calculated. The optical band gap of the CuAlS2 film was found to be 3.45 eV. The optical constants such as refractive index, extinction coefficient and dielectric constants of the CuAlS2 film were determined. The refractive index dispersion curve of the film obeys the single oscillator model. Optical dispersion parameters Eo and Ed developed by Wemple-DiDomenico were calculated and found to be 3.562 and 12.590 eV. 相似文献
6.
Present investigation reports, spray pyrolytic deposition of Mn: Co3O4 thin films onto the stainless steel by spray pyrolysis, at the deposition temperature 573 ± 2 K via aqueous route. Prepared electrodes were characterized structurally and morphologically by means of XRD and SEM. Also optical and electrochemical characterizations were carried out in depth. Structural characterization confirms face centered cubic and tetragonal body centered crystal structures for Co3O4 and Mn3O4 respectively. The rough granular morphology is observed form SEM. Electrochemical study reveals the pseudo capacitive as well as double layer behavior with optimum specific capacitance 485.29 F/g at the scan rate 1 mV/s in 1 M KOH electrolyte. Specific energy, specific power and columbic efficiency were calculated using chronopotentiometric technique. Electrochemical impedance spectroscopy was carried out in the frequency range 1 mHz–1 MHz. Randles equivalent circuit parameters associated with the operative cell are reported. 相似文献
7.
在室温及不同的氧氩比条件下,采用射频磁控溅射Ag层和直流磁控溅射SnO2层,在载玻片衬底上制备出了SnO2/Ag/SnO2多层薄膜.用霍尔效应测试仪、四探针电阻测试仪和紫外-可见-近红外光谱仪等表征了薄膜的电学性质和光学性质.实验结果表明:当氧氩比为1:14时,所制得的薄膜的光电性质优良指数最大,为1.69×10-2 Ω-1;此时,薄膜的电阻率为9.8×10-5 Ω·cm,方电阻为9.68 Ω/sq,在400~800 nm可见光区的平均光学透射率达85%;并且,在氧氩比为1:14时,利用射频磁控溅射Ag层和直流磁控溅射SnO2层在PET柔性衬底上制备出了光电性质优良的柔性透明导电膜,其在可见光区的平均光学透过率达85%以上,电阻率为1.22×10-4 Ωcm,方电阻为12.05 Ω/sq. 相似文献
8.
Thin films of ZnWO4 and CdWO4 were prepared by spray pyrolysis and the structural, optical, and luminescence properties were investigated. Both ZnWO4 and CdWO4 thin films showed a broad blue-green emission band. The broad band of ZnWO4 films was centered at 495 nm (2.51 eV) consisted of three bands at 444 nm (2.80 eV), 495 nm (2.51 eV) and 540 nm (2.30 eV). The broad band of CdWO4 films at 495 nm (2.51 eV) could be decomposed to three bands at 444 nm (2.80 eV), 495 nm (2.51 eV) and 545 nm (2.28 eV). These results are consistent with emission from the WO66− molecular complex. The luminance and efficiency for ZnWO4 film at 5 kV and 57 μA/cm2 were 48 cd/m2 and 0.22 lm/w, respectively, and for CdWO4 film the values were 420 cd/m2 and 1.9 lm/w. 相似文献
9.
In this study, SnO2/TiO2 thin films are fabricated on SiO2/Si and Corning glass 1737 substrates using a R.F. magnetron sputtering process. The gas sensing properties of these films under an oxygen atmosphere with and without UV irradiation are carefully examined. The surface structure, morphology, optical transmission characteristics, and chemical compositions of the films are analyzed by atomic force microscopy, scanning electron microscopy and PL spectrometry. It is found that the oxygen sensitivity of the films deposited on Corning glass 1737 substrates is significantly lower than that of the films grown on SiO2/Si substrates. Therefore, the results suggest that SiO2/Si is an appropriate substrate material for oxygen gas sensors fabricated using thin SnO2/TiO2 films. 相似文献
10.
We have investigated the optical properties of sol-gel thin films of tin dioxide (SnO2) codoped with Er3+-Yb3+ as a function of Yb3+ concentration. The Judd-Ofelt model has been applied to absorption intensities of Er3+ (4f11) transitions to establish the so-called Judd-Ofelt intensity parameters: Ω2, Ω4, Ω6. Various spectroscopic parameters were obtained to evaluate their dependence and the potential of the samples as a laser material in the eye-safe laser wavelength (1.53 μm) as a function of Yb3+ concentration. An amelioration of the quality factor Ω4/Ω6 was found with Yb content. Both the IR photoluminescence (PL) intensity and the up-conversion emission, from Er3+ ion in SnO2, were found to increase with Yb concentration. We show that the Yb3+ ion acts as sensitizer for Er3+ ion and contributes largely to the improvement of the spectroscopic properties of SnO2:Er. The mechanism of up-conversion emission is discussed and a model is proposed. The results showed that sol-gel SnO2 is promising gain media for developing the solid-state 1.5 μm optical amplifiers and tunable up-conversion lasers. 相似文献
11.
The extensive investigation of the annealing effect in nitrogen atmosphere on the structural optical and electrical properties of chemically deposited CdS films on SnO2 has been performed. The as-deposited film shows 2.45 eV band gap (Eg) and decreases with increasing annealing temperature. The film annealed at 623 K having pure hexagonal phase (a = 4.14 Å, c = 6.71 Å for [1 0 0] plane) and Eg = 2.36 eV shows 10 times higher conductivity for all temperature range, and shows two different activation energies Ea = 0.114 eV and Ea = 0.033 eV for the temperature range 395 K ≤ T ≤ 515 K and 515 K ≤ T ≤ 585 K, respectively. The structural parameters such as dislocation density, strain and optical parameters such as absorption and extinction coefficient are calculated and compared for all the films. 相似文献
12.
Antimony-doped tin oxide thin films have a range of technological applications as conductive coatings, and sol-gel processing seems to offer some advantages over other coating techniques. In this study antimony-doped tin oxide (ATO) thin films have been prepared by the sol-gel dip-coating (SGDC) process, using tin (II) chloride dehydrate (SnCl2, 2H2O) and antimony (III) chloride (SbCl3) as host and dopant precursors respectively. The structure of the (ATO) powders was analysed by X-ray diffraction (XRD) and the microstructure of the thin films by atomic force microscopy (AFM). These investigations show that the structure is tetragonal rutile type and that an increase in Sb-doping decreases the crystallite size of the (ATO) particles. To analyze the impedance spectroscopy data, the Nyquist (Z″ vs. Z′) plots as well as the representation of imaginary (Z″) and real (Z′) parts of impedance vs. frequency were used. The Nyquist plots suggest that only the grain boundaries are responsible in the conduction mechanism of the material. From the variation of lnσ vs. inverse of absolute T we have deduced the activation energy found to be 0.87 eV. 相似文献
13.
Gd-doped SnO2 nanoparticles were chemically prepared doping 0-12.5% Gd into SnO2 and calcined at 600 °C. X-ray diffraction and Fourier transformed infrared spectroscopy measurements show the formation of single phase of Sn1−xGdxO2 up to x=0.0625 while at x=0.125, an additional secondary phase of tetragonal GdO2 (not cubic Gd2O3) is detected. The transmission electron microscopy studies show that the individual particles are single crystalline with an average size in the range of 10-12 nm. Magnetization measurements show the absence of ferromagnetic and antiferromagnetic ordering in all samples; however surface spin effects and enhanced Gd-O-Gd interactions are proposed to account for the observed magnetic properties of the samples. 相似文献
14.
Eu-doped Y2O3 particles with spherical shape and fine size were prepared by spray pyrolysis. The cathodoluminescence of Y2O3:Eu3+ powder was optimized by substituting small amount of zinc atoms in place of yttrium sites. As a result, the optimized (Y, Zn)2O3:Eu3+ phosphor showed 60% improved cathodoluminescence compared with Y2O3:Eu3+ particles. The prepared (Y, Zn)2O3:Eu3+ phosphor had spherical shape and 0.726 μm in mean size. Using these particles, the thickness of the phosphor film was controlled by varying the phosphor loading. The brightness and luminous efficiency of phosphor films prepared were monitored with varying the accelerating voltage ranges from 4 to 14 kV. The dependency of the luminous efficiency on the accelerating voltage was very sensitive to the phosphor loading. As increasing the accelerating voltage from 4 to 14 kV, the brightness of phosphor films prepared was monotonically increased from 200 to 1085 cd/cm2, but the saturation in the luminous efficiency appeared at 10 kV. The highest efficiency was achieved when the number of phosphor-particles layer was about 3. More details about the luminous efficiency and brightness were discussed with changing the phosphor loading. 相似文献
15.
Hui Yang Ruilin Han Yu Yan Xiaobo Du Qing Zhan Hanmin Jin 《Journal of magnetism and magnetic materials》2012
The electronic structures and magnetic properties of Zn- and Cd-doped SnO2 are investigated using first-principles calculations within the generalized gradient approximation (GGA) and GGA+U scheme. The substitutional Zn and Cd atoms introduce holes in the 2p orbitals of the O atoms and the introduced holes are mostly confined to the minority-spin states. The magnetic moment induced by doping mainly comes from the 2p orbitals of the O atoms, among which the moment of the first neighboring O atoms around the dopant are the biggest. The U correction for the anion-2p states obviously increases the moment of the first neighboring O atoms and transforms the ground states of the doped SnO2 from half-metallic to insulating. The magnetic coupling between the moments induced by two dopants is ferromagnetic and the origin of ferromagnetic coupling can be attributed to the p–d hybridization interaction involving holes. 相似文献
16.
M. Kovendhan D. Paul JosephE. Senthil Kumar A. SendilkumarP. Manimuthu S. SambasivamC. Venkateswaran R. Mohan 《Applied Surface Science》2011,257(18):8127-8133
The effect of Li (0-5 wt%) doping on the properties of WO3 thin films deposited using an automated homemade spray pyrolysis unit is studied. Change in structural and optical properties is observed on doping with Li. The XRD patterns shows that undoped WO3 film has an orthorhombic phase while the Li (1-5 wt%) doped WO3 films have tetragonal phase. The SEM and AFM images confirm relatively smooth surface of Li doped WO3 films compared to undoped WO3 film. Transmission spectra reveal that the transparency of the Li-doped films is much greater than that of undoped film. From the transmission data, the direct, indirect bandgap and phonon energies were calculated. Room temperature photoluminescence spectra showed pronounced blue emission on doping with Li. 相似文献
17.
Iron oxide thin films were prepared by spray pyrolysis technique onto glass substrates from iron chloride solution. They were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and (UV-vis) spectroscopy. The films deposited at Ts ≤ 450 °C were amorphous; while those produced at Tsub = 500 °C were polycrystalline α-Fe2O3 with a preferential orientation along the (1 0 4) direction. By observing scanning electron microscopy (SEM), it was seen that iron oxide films were relatively homogeneous uniform and had a good adherence to the glass substrates. The grain size was found (by RX) between 19 and 25 nm. The composition of these films was examined by X-ray photoelectron spectroscopy and electron probe microanalysis (EPMA). These films exhibited also a transmittance value about 80% in the visible and infrared range. The cyclic voltammetry study showed that the films of Fe2O3 deposited on ITO pre-coated glass substrates were capable of charge insertion/extraction when immersed in an electrolyte of propylene carbonate (PC) with 0.5 M LiCLO4. 相似文献
18.
SnO2 thin film was grown on Si substrate using the low pressure chemical vapor deposition (LPCVD) method. The SnO2 thin film was grown in the direction of (110) as deposition time increased. The atomic ratio of O decreased by 62.4, 57.6, and 45.6%, and the thickness of the thin film increased to 0.2, 0.3, and 0.7 ? as the deposition time increased to 10, 20, and 30 min, respectively. The interface of the thin film was examined using high-resolution transmission electron microscope (HRTEM) and energy dispersive spectroscopy (EDS) analysis. The SiO2 layer was observed at between the SnO2 thin film and the Si substrate. This layer decreased in thickness as the deposition time increased, which indicates that the deposition time affected the interface of the thin film. 相似文献
19.
(2 0 2)/(2 2 0)-oriented epitaxial β-FeSi2 thin films were deposited on textured Si (1 0 0) substrate by magnetron sputtering. The influences of thickness and annealing temperature on the β-FeSi2 crystallization were studied to find the optimal condition. The results of surface morphology and optical property measurements showed that the inverted pyramid array in the surface of β-FeSi2 thin films could reduce the surface reflection of β-FeSi2. In dark condition, the β-FeSi2/textured-Si heterojunction showed diode property with rectifying ratio of 2.89 × 105 and built-in potential of 0.58 V. These results indicated the potential application of textured Si substrate in β-FeSi2 solar cells. 相似文献
20.
SnO2:Eu and SnO2:Eu nanoparticles dispersed in silica matrix were prepared at a relatively low temperature of 185 °C in ethylene glycol medium. For as-prepared SnO2:Eu nanoparticles there exists a weak energy transfer from the SnO2 host to the Eu3+ ions. However, the energy transfer can be significantly improved by dispersing the Eu3+-doped SnO2 nanoparticles in silica matrix. Effective shielding of surface Eu3+ ions in SnO2:Eu nanoparticles from the stabilizing ligand by silica matrix is the reason for the improved extent of energy transfer. Increase in asymmetric ratio of luminescence (ratio of the intensity of the electric dipole allowed transition, 5D0→7F2, to magnetic dipole allowed transition, 5D0→7F1) for SnO2:Eu nanoparticles dispersed in silica compared to that of SnO2:Eu nanoparticles, has been attributed to the distorted environment around surface Eu3+ ions brought about by the presence of both tin and silicon structural units. 119Sn and 29Si MAS NMR studies on this sample confirmed that there is no interaction between the tin and silicon structural units even after heating the samples at 900 °C. 相似文献