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1.
In2O3 thin films were prepared by the thermal oxidation of amorphous InSe films in air atmosphere. The structure, morphology and composition of the thermal annealed products were characterized by X-ray diffraction (XRD), scanning electron microscopy and energy-dispersive spectroscopy, respectively. The XRD patterns indicate that the as-deposited InSe films were amorphous and they fully transformed into polycrystalline In2O3 films with a cubic crystal structure in the preferential (222) orientation at a temperature around 600 °C. The optical energy gap of 3.66 eV was determined at room temperature by transmittance and reflectance measurements using UV-vis-NIR spectroscopy. A preliminary characterization shows that these films have a promising response towards NO2 gas at a working temperature around 180 °C.  相似文献   

2.
The correlations between microstructure of nanocrystalline TCO SnO2 and In2O3 and parameters of oxygen chemisorption are analyzed. Nanocrystalline SnO2 and In2O3 were prepared by wet chemical method. The sample's microstructure was characterized by TEM, XRD and low-temperature nitrogen adsorption. Electrical properties of TCO were studied at 200-400 °C depending on the oxygen partial pressure. Increase of TCO grain size leads to the increase of the fraction of atomic forms of chemisorbed oxygen at the fixed temperature. It could be due to the decrease of surface barrier resulting in the decrease of activation energy of dissociation of molecular ion O2(ads).  相似文献   

3.
This paper reports the influence of In2O3 film structure on gas-sensing characteristics measured in steady state and transient modes. Films were deposited by spray pyrolysis from InCl3–water solutions. Correlation between gas-sensing parameters and structural parameters such as film thickness (20–400 nm), grain size (10–70 nm), refractive index and film texture (I(400)/I(222)) were established. It was shown that grain size and porosity are the parameters of In2O3 films that best control gas response to ozone. In the detection of reducing gases, the influence of film structure is less important. Decreases in film thickness, grain size and degree of texture are the best way to decrease time constants of the gas response of In2O3-based gas sensors.  相似文献   

4.
Indium Tin Oxide (ITO) thin films have been deposited by the Sol-Gel Dip-Coating technique, the starting solutions being prepared from chlorides. These multilayered films were crystallized by means of a classical heat treatment at temperatures ranging from 500 to 600 °C. Five stacked layers are necessary to obtain a global electrical resistivity value of 2.9×10−3 Ω cm, for 500 °C annealed film. The paper focuses on the study of the structure of such multilayered deposits, and on the densification process, using transmission electron microscopy, Rutherford Back-scattering Spectrometry and electrical resistivity measurements. This analysis reveals structural inhomogeneities and different crystallite growth processes as a function of annealing temperature and number of deposited layers.  相似文献   

5.
Role of surface properties of MoO3-doped SnO2 thin films on NO2 gas sensing   总被引:1,自引:0,他引:1  
Jaswinder Kaur 《Thin solid films》2010,518(14):3982-260
The role of surface morphology of MoO3-doped SnO2 thin film on the gas sensing properties is analyzed. SnO2 thin films doped with 1, 3, 5 and 10 wt% MoO3 are prepared by sol-gel spin coating process. Structural and morphological properties are studied using glancing angle X-ray diffractometer, atomic force microscopy, transmission electron microscopy and high resolution transmission electron microscopy. Energy dispersive X-ray analysis and X-ray photoelectron spectroscopy studies are used for chemical analysis. A good correlation is found between the characteristics of the surface and gas sensing properties of these films. MoO3 addition is found responsible for increase in acidic nature of films which in turn increases their sensitivity and selectivity towards NO2 gas.  相似文献   

6.
This study examined the characteristics of Ga:In2O3 (IGO) co-sputtered Zn:In2O3 (IZO) films prepared by dual target direct current (DC) magnetron sputtering at room temperature in a pure Ar atmosphere for transparent electrodes in IGZO-based TFTs. Electrical, optical, structural and surface properties of Ga and Zn co-doped In2O3 (IGZO) electrodes were investigated as a function of IGO and IZO target DC power during the co-sputtering process. Unlike semiconducting InGaZnO4 films, which were widely used as a channel layer in the oxide TFTs, the co-sputtered IGZO films showed a high transmittance (91.84%) and low resistivity (4.1 × 10− 4 Ω cm) at optimized DC power of the IGO and IZO targets, due to low atomic percent of Ga and Zn elements. Furthermore, the IGO co-sputtered IZO films showed a very smooth and featureless surface and an amorphous structure regardless of the IGO and IZO DC power due to the room temperature sputtering process. This indicates that co-sputtered IGZO films are a promising S/D electrode in the IGZO-based TFTs due to their low resistivity, high transmittance and same elements with channel InGaZnO4 layer.  相似文献   

7.
Considering practical applications in electronic devices, we studied the growth of In2O3 thin films on amorphous glasses by magnetron sputtering at room temperature and annealing effect on the structural and electrical properties. The vacuum annealed In2O3 thin films display a grain size enlargement and preferential orientation. Electrical characterization shows that the vacuum annealed In2O3 thin films exhibit a significant enhancement of both electron density and mobility, while air ambient annealing leads to a remarkable drop. The mechanism of the electrical characteristic changes in In2O3 thin films by annealing is explored by using different scattering mechanisms. Finally, a thin film transistor device using vacuum annealed In2O3 nano-meter thin films as active channel material is demonstrated.  相似文献   

8.
An amorphous transparent conductive oxide thin film of molybdenum-doped indium oxide (IMO) was prepared by reactive direct current magnetron sputtering at room temperature. The films formed on glass microscope slides show good electrical and optical properties: the low resistivity of 5.9 × 10− 4 Ω cm, the carrier concentration of 5.2 × 1020 cm− 3, the carrier mobility of 20.2 cm2 V− 1 s− 1, and an average visible transmittance of about 90.1%. The investigation reveals that oxygen content influences greatly the carrier concentration and then the photoelectrical properties of the films. Atomic force microscope evaluation shows that the IMO film with uniform particle size and smooth surface in terms of root mean square of 0.8 nm was obtained.  相似文献   

9.
Zirconium doped indium oxide thin films were deposited by the atomic layer deposition technique at 500 °C using InCl3, ZrCl4 and water as precursors. The films were characterised by X-ray diffraction, energy dispersive X-ray analysis and by optical and electrical measurements. The films had polycrystalline In2O3 structure. High transparency and resistivity of 3.7×10−4 Ω cm were obtained.  相似文献   

10.
S. Kaleemulla 《Materials Letters》2007,61(21):4309-4313
Indium oxide (In2O3) thin films were prepared by flash evaporated technique under various substrate temperatures in the range of 303-673 K and systematically studied the structural, electrical and optical properties of the deposited films. The films formed at substrate temperatures of < 373 K were amorphous while those deposited at higher substrate temperatures (≥ 373 K) were polycrystalline in nature. The optical band gap of the films decreased from 3.71 eV to 2.86 eV with the increase of substrate temperature from 303 K to 673 K. Figure of merit of the films increased from 2.8 × 103 Ω 1 cm 1 to 4.2 × 103 Ω 1 cm 1 with increasing substrate temperature from 303 K to 573 K, thereafter decreased to 2.2 × 103 Ω 1 cm 1 at higher temperature of 673 K.  相似文献   

11.
R.K. Gupta  S.R. Mishra 《Thin solid films》2008,516(10):3204-3209
Highly transparent and conducting thin films of gadolinium doped indium oxide, which have high electron mobility, were deposited on quartz substrate to study the effect of growth temperature and oxygen pressure on their structural, optical, and electrical properties. X-ray diffraction study reveals that these films are randomly oriented on the quartz surface. The average particle size of the films grown at 600 °C was calculated to be ∼ 23 nm. The optical transparency of the films increases with an increase in the growth temperature. The film transparency is also found to increase with increased oxygen pressure during deposition. The electrical properties of these films strongly depend on both the growth temperature and the oxygen pressure. Analysis of the electrical data shows that the mobility of the films increases with increase in the growth temperature.  相似文献   

12.
Thin films of indium oxide have been deposited using the atomic layer deposition (ALD) technique using In(acac)3 (acac = acetylacetonate, pentane-2,4-dione) and either H2O or O3 as precursors. Successful growth using In(acac)3 is contradictory to what has been reported previously in the literature [J.W. Elam, A.B.F. Martinson, M.J. Pellin, J.T. Hupp, Chem. Mater. 18 (2006) 3571.]. Investigation of the dependence of temperature on the deposition shows windows where the growth rates are relatively unaffected by temperature in the ranges 165–200 °C for In(acac)3 and H2O, 165–225 °C for In(acac)3 and O3. The growth rates obtained are of the order 20 pm/cycle for In(acac)3 and H2O, 12 pm/cycle for In(acac)3.  相似文献   

13.
Polycrystalline ZnO-In2O3 thin films were prepared by thermal oxidation in air of metallic Zn-In films deposited onto glass substrates by thermal evaporation under vacuum. Different oxidation conditions (oxidation temperature, oxidation time, heating rate) were used in order to prepare homogeneous films that can be used as gas sensors. Polycrystalline structure of the as-obtained films was confirmed by X-ray and electron diffraction investigations. The electrical conductivity of various thin film samples ranged between 0.84 and 6.44 (Ω cm)− 1.Gas sensitivity to six different gasses (ammonia, methane, LPG, acetone, ethanol and formaldehyde) was evaluated and it was found that the highest sensitivity was obtained for ammonia.  相似文献   

14.
The nanocrystalline powders of pure and La3+-doped In2O3 with cubic structure were prepared by a simple hydrothermal decomposition route. The structure and crystal phase of the powders were characterized by X-ray diffraction (XRD) and microstructure by transmission electron microscopy (TEM). All the compositions exhibited a single phase, suggesting a formation of solid solution in the concentration of doping investigated. Gas-sensing properties of the sensor elements were tested by mixing a gas in air at static state, as a function of concentration of dopant, operating temperature and concentrations of the test gases. The pure In2O3 exhibited high response towards H2S gas at an operating temperature 150 °C. Doping of In2O3 with La3+ increases its response towards H2S and La3+ (5.0 wt.% La2O3)-doped In2O3 showed the maximum response at 125 °C. The selectivity of the sensor elements for H2S against different reducing gases was studied. The results on response and recovery time were also discussed.  相似文献   

15.
The electronic structural analysis of the conductive transparent films was carried out using bulk sensitive hard X-ray photoelectron spectroscopy (HAXPES). The In2O3-ZnO film has amorphous structure before and after annealed, and the conduction band spectrum around Fermi level showed the similar spectra with that of as-deposited amorphous In2O3 film. In these amorphous films, the conduction band minimum locates at the deeper level than the crystalline In2O3 film. The electronic state which comes from randomness of amorphous structure possibly exists around this level or below. These electrons are expected to act as scattering center. We concluded that the electron mobility depends on the density of this electronic state.  相似文献   

16.
Indium tin oxide (ITO) thin films were deposited on quartz substrates by direct current magnetron sputtering and annealed in N2 and air. The normal incidence transmittance of the films was measured by a spectrophotometer. The electrical parameters such as carrier concentration, mobility and resistivity were investigated by van der Pauw method. An optical model has been proposed to simulate the optical constants and thicknesses of the films from transmittance data, which combines the Forouhi-Bloomer model and modified Drude model. The relaxation energy in the Drude term is taken as energy-dependent for a better fitting in the visible spectral range. The simulated transmittance is in good agreement with the measured spectrum in the whole measurement wavelength range. The electrical parameters obtained from the optical simulation are well consistent with those measured electrically by van der Pauw method. The experimental results also indicate that the different post-deposition annealing treatments yield the distinct optical and electrical properties of ITO films.  相似文献   

17.
High quality films of In2O3 and tin-doped In2O3 were prepared by a novel activated reactive evaporation technique developed for use with resistively heated evaporation sources. Transparent conducting coatings of In2O3 have a sheet resistance of 80 Ω/□ with an optical transparency of more than 95% in the 0.4–1.6 μm wavelength range. Thin (0.4 μm) In2O3(Sn) films have a sheet resistance of 25 Ω/□ and an optical transparency as high as 99% at some wavelengths with an average transmission between 0.4 and 1.6 μm of 96%. Thicker films have a sheet resistance as low as 2.2 Ω/□. A comparison of the properties of In2O3(Sn) films with those of transparent conducting films produced by other techniques is made.  相似文献   

18.
TiO2 films were grown by an advanced pulsed laser deposition method (PLD) on ITO substrates to be used as functional electrodes in the manufacturing of solar cells. A pure titanium target (99.99%) was irradiated by a Nd:YAG laser (355 and 532 nm, 5 ns, 35 mJ, 3 J/cm2) in an oxygen atmosphere at different pressures (20-160 mTorr) and at room temperature. After deposition, the films were subjected to an annealing process at 350 °C. The film structure, surface morphology, thickness, roughness, and optical transmission were investigated. Regardless of the wavelength used, the films deposited at room temperature presented only Ti2O and TiO peaks. After thermal treatment, the TiO2 films became strongly crystalline, with a tetragonal structure and in the anatase phase; the threshold temperature value was 250 °C. The deposition rate was in the range of 0.035-0.250 nm/pulse, and the roughness was 135-305 nm. Optical transmission of the films in the visible range was between 40% and 60%.  相似文献   

19.
Highly oriented and transparent indium tin oxide (ITO) films have been deposited onto glass substrates by radio frequency magnetron sputtering at 648 K, under an oxygen partial pressure of 1 Pa. The effect of the sputtering power and annealing was studied. Transmission was measured with a double beam spectrometer and electrical analysis using four probe and Hall effect setup. Structural characterization of the films was done by X-ray diffraction. Characterization of the coatings revealed an electrical resistivity below 6.5 × 10− 3 Ω cm. The ITO films deposited at 648 K were amorphous, while the crystallinity improved after annealing at 700 K. The optical transmittance of the film was more than 80% in the visible region. The surface morphology examined by scanning electron microscopy appears to be uniform over the entire surface area, after annealing. The NO2 sensing properties of the ITO films were investigated. At a working temperature of 600 K, the ITO sensor showed high sensitivity to NO2 gas, at concentrations lower than 50 ppm.  相似文献   

20.
Zinc oxide (ZnO) thin films were prepared using thermal oxidation of zinc metallic films deposited by vacuum evaporation. The structure of the as-obtained ZnO films was investigated by X-ray diffraction technique and atomic force microscopy. Investigations revealed that ZnO thin films were polycrystalline and have a hexagonal (wurtzit) structure. The structural parameters depend on the oxidation conditions. The wettability of the films was studied and was observed that under UV-irradiation the ZnO films become super-hydrophilic. Optical properties of the films were investigated and it was observed that, in visible domain, optical transmittance ranged between 85 and 95% and optical reflectance is less 15%.  相似文献   

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