直流电弧放电法合成In2O3纳米粒子

电弧放电法因能在瞬间产生高温使原料气化而成为一种高效的纳米材料制备方法。以金属In为原料,在无催化剂的条件下,采用直流电弧放电法直接合成了In2O3纳米粒子。XRD、SEM和TEM结果表明所制备的In2O3纳米粒子为立方结构,形貌为结晶良好的八面体,平均粒径为60～120nm。纳米粒子之间以点接触和面接触相连。     

Characterization of wurtzite indium nitride synthesized from indium oxide by In-115 MAS NMR spectroscopy

Wurtzite indium nitride (w-InN) powders synthesized from the reaction of indium oxide (In₂O₃) with ammonia were characterized by ¹¹⁵In magic-angle spinning (MAS) NMR spectroscopy and nitrogen analyzer. The powders were not a single phase of w-InN but a mixture of w-InN and In-incorporated w-InN. The incorporation of In metal in InN lattice due to thermal decomposition caused the ¹¹⁵In MAS NMR peak of w-InN to be downfield shifted and might be responsible for the increase in the band gap of w-InN.     

High-mobility molybdenum doped indium oxide

The effects of molybdenum doping (0-12 at.%) on the optical and electrical properties of In₂O₃ were investigated using combinatorial sputter deposition in combination with combinatorial analysis techniques. The electrical properties are highly dependent on the deposition temperature and the molybdenum doping concentration. A minimum temperature between 300 °C and 400 °C is needed to activate the carriers. The maximum mobility is observed at a Mo concentration of 4.4 at.% and is 65.3 cm² V^− 1 s^− 1. The maximum conductivity is observed at 5.9 at.% molybdenum doping and is equal to 5000 Ω^− 1 cm^− 1. The carrier concentration increases with increasing molybdenum doping to a maximum value of 6.6·10²⁰ cm^− 3 at a doping concentration of 8.6 at.%. The optical transparency is high (> 80%) in a wide spectral range that is dependent on the process parameters.     

Preparation of indium oxide powders by microwave plasma dehydration of indium hydroxide powders

Indium oxide was prepared from the dehydration of indium hydroxide using atmospheric-pressure microwave air plasma. Compared with the conventional thermal plasma processing that was performed with the vapor phase reaction, the solid-state reaction was attempted in this study because microwave plasma has an intermediate temperature that is comparable to the melting temperature of inorganic materials and between those of the electric furnace and the thermal plasma. The results were compared with those with the electric furnace and the thermal plasma. With both the microwave plasma and the electric furnace, the macro-morphologies of the raw material were maintained, which indicates successful dehydration. However, the micro-morphologies differed. The product of the microwave plasma had a smooth surface, whereas the product of the electric furnace had a cracked and rough surface. The cracks were regarded as the results of the poor diffusion of the dissociated water. In the microwave plasma, the high temperature and the fast heating rate enhanced the diffusion and controlled the formation of cracks. With the application of the thermal plasma, the nanoparticles were prepared due to the vaporization of the dehydrated material. Thus, the microwave plasma is considered applicable to the solid-state reaction accompanying degassing, without a change in the microstructure of the raw material.     

Refractive indices of textured indium tin oxide and zinc oxide thin films

The refractive indices of textured indium tin oxide (ITO) and zinc oxide (ZnO) thin films were measured and compared. The ITO thin film grown on glass and ZnO buffered glass substrates by sputtering showed distinct differences; the refractive index of ITO on glass was about 0.05 higher than that of ITO on ZnO buffered glass in the whole visible spectrum. The ZnO thin film grown on glass and ITO buffered glass substrates by filtered vacuum arc also showed distinct differences; the refractive index of ZnO on glass was higher than that of ZnO on ITO buffered glass in the red and green region, but lower in the blue region. The largest refractive index difference of ZnO on glass and ITO buffered glass was about 0.1 in the visible spectrum. The refractive index variation was correlated with the crystal quality, surface morphology and conductivity of the thin films.     

分子模板法合成介孔氧化锡

室温下在水溶液体系中,以非离子表面活性剂壬基酚聚氧乙烯醚和阳离子表面活性剂十六烷基三甲基溴化铵为模板,五水四氯化锡为无机前驱体合成介孔氧化锡,其孔径为2～10nm.通过N 2-吸附/脱附、XRD、TG-DTA等检测手段对产物进行分析.通过控制壬基酚聚氧乙烯醚和十六烷基三甲基溴化铵的比例,可调节孔径的大小及比表面积等.     

Transparent heaters based on solution-processed indium tin oxide nanoparticles

We demonstrate transparent heaters constructed on glass substrates using solution-processed indium tin oxide (ITO) nanoparticles (NPs) and their heating capability. The heat-generating characteristics of the heaters depended significantly on the sintering temperature at which the ITO NPs deposited on a glass substrate by spin-coating were transformed thermally into a solid film. The steady-state temperature of the ITO NP film sintered at 400 °C was 163 °C at a bias voltage of 20 V, and the defrosting capability of the film was confirmed by using dry-ice.     

Crystallization of amorphous indium zinc oxide thin films produced by radio-frequency magnetron sputtering

In this work we studied indium zinc oxide (IZO) thin films deposited by r.f. magnetron sputtering at room temperature. The films were annealed at high temperature (1100 K) in vacuum, and the oxygen exodiffusion was monitored in-situ. The results showed three main peaks, one at approximately 600 K, other at approximately 850 K and the last one at 940 K, which are probably from oxygen bonded in the film surface and in the bulk, respectively. The initial amorphous structure becomes microcrystalline, according to the X-ray diffraction. The electrical conductivity of the films decreases (about 3 orders of magnitude), after the annealing treatment.This behavior could be explained by the crystallization of the structure, which affects the transport mechanism. Apart from the changes in the material structure, a small variation was observed on the absorption coefficient.     

Investigation on indium concentration dependence of solution processed indium tin oxide thin film transistors

The effect of the indium content in indium tin oxide (ITO) films fabricated using a solution-based process and ITO channel thin film transistors (TFTs) was examined as a function of the indium mole ratio. The carrier concentration and resistivity of the ITO films could be controlled by the appropriate treatments. The TFTs showed an increase in the off-current due to the enhanced conductivity of the ITO channel layer with increasing indium mole ratios, producing an increase in the field effect mobility. The characteristics of the a-ITO channel TFT showed the best performance (μ_FE of 3.0 cm² V^− 1 s^− 1, V_th of 2.0 V, and S value of 0.4 V/decade) at In:Sn = 5:1.     

Ultraflat indium tin oxide films prepared by ion beam sputtering

Indium tin oxide (ITO) films with a smooth surface (root-mean-square roughness; R_rms=0.40 nm) were made using a combination of the deposition conditions in the ion beam-sputtering method. Sheet resistance was 13.8 Ω/sq for a 150-nm-thick film grown at 150 °C. Oxygen was fed into the growth chamber during film growth up to 15 nm, after which, the oxygen was turned off throughout the rest of the deposition. The surface of the films became smooth with the addition of ambient oxygen but electrical resistance increased. In films grown at 150 °C with no oxygen present, a rough surface (R_rms=2.1 nm) and low sheet resistance (14.4 Ω/sq) were observed. A flat surface (R_rms=0.5 nm) with high sheet resistance (41 Ω/sq) was obtained in the films grown with ambient oxygen throughout the film growth. Surface morphology and microstructure of the films were determined by the deposition conditions at the beginning of the growth. Therefore, fabrication of ITO films with a smooth surface and high electrical conductivity was possible by combining experimental conditions.     

Growth and characterization of indium oxide thin films prepared by spray pyrolysis

Highly transparent and conducting indium oxide thin films are prepared on glass substrates from precursor solution of indium chloride. These films are characterized by X-ray diffraction, scanning electron microscopy and optical transmission. The preferential orientation of these films is found to be sensitive to deposition parameters. A comparative study has been made on the dependence on the thickness of the film on substrate temperatures with aqueous solution and 1:1 C₂H₅OH and H₂O as precursors. Films deposited at optimum conditions have 167 nm thickness and exhibited a resistivity of 2.94 × 10⁻⁴ Ω m along with transmittance better than 82% at 550 nm. The analytical expressions enabling the derivation of the optical constants of these films from their transmission spectrum only have successfully been applied. Finally, the refractive index dispersion is discussed in terms of the single-oscillator Wemple and Didomenico model.     

Room temperature ferromagnetic multilayer thin film based on indium oxide and iron oxide for transparent spintronic applications

Pulsed laser deposition technique is used for fabrication of multilayer thin film of indium oxide (In₂O₃) and iron oxide (Fe₃O₄). X-ray diffraction study shows that In₂O₃ film is highly oriented along (222) direction. The optical band gap of the multilayer is observed to be 3.65 eV. The film shows n-type behavior with resistivity, carrier concentration, and mobility of 5.59 × 10⁻⁴ Ω.cm, 2.33 × 10²⁰ cm⁻³, and 48 cm ²v⁻¹ s⁻¹ respectively. Magnetic measurement shows that the film is ferromagnetic at room temperature. Hysteresis measurements at 5 K after field cooling show a shift and broadening of the hysteresis loop, which is due to exchange bias coupling.     

Room temperature indium tin oxide by XeCl excimer laser annealing for flexible display

A XeCl excimer laser (λ=308 nm) has been used to anneal Indium Tin Oxide (ITO) films deposited at 25 °C using DC magnetron sputtering. With increasing laser fluence, the film crystallinity was improved while retaining the as-deposited 111 texture. As a result of laser irradiation, the sheet resistance of 100 nm ITO films decreased from 191 Ω/□ (1.91×10⁻³ Ω cm) to 25 Ω/□ (2.5×10⁻⁴ Ω cm), while the optical transmittance in the visible range increased from 70% to more than 85%. Surface roughness and etching properties were also significantly improved following laser annealing.     

Properties of indium tin oxide films deposited using High Target Utilisation Sputtering

Indium tin oxide (ITO) films were deposited on soda lime glass and polyimide substrates using an innovative process known as High Target Utilisation Sputtering (HiTUS). The influence of the oxygen flow rate, substrate temperature and sputtering pressure, on the electrical, optical and thermal stability properties of the films was investigated. High substrate temperature, medium oxygen flow rate and moderate pressure gave the best compromise of low resistivity and high transmittance. The lowest resistivity was 1.6 × 10^− 4 Ω cm on glass while that on the polyimide was 1.9 × 10^− 4 Ω cm. Substrate temperatures above 100 °C were required to obtain visible light transmittance exceeding 85% for ITO films on glass. The thermal stability of the films was mainly influenced by the oxygen flow rate and thus the initial degree of oxidation. The film resistivity was either unaffected or reduced after heating in vacuum but generally increased for oxygen deficient films when heated in air. The greatest increase in transmittance of oxygen deficient films occurred for heat treatment in air while that of the highly oxidised films was largely unaffected by heating in both media. This study has demonstrated the potential of HiTUS as a favourable deposition method for high quality ITO suitable for use in thin film solar cells.     

Successive deposition of layered titanium oxide/indium tin oxide films on unheated substrates by twin direct current magnetron sputtering

Layered titanium oxide/indium tin oxide (TiO₂/ITO) films were successively deposited on unheated glass substrates in situ using a twin direct current magnetron sputtering system. The layered TiO₂/ITO films exhibited a strongly polycrystalline structure that comprises anatase and rutile phases, as revealed by X-ray diffraction and Raman spectra. The X-ray photoelectron spectrum of Ti2p also verified the stoichiometric state of titanium oxide near the surface. The photo-induced hydrophilic properties of the films were determined from changes in the water contact angles under ultra-violet (UV) irradiation. The results revealed that the layered TiO₂/ITO films possessed a dissipated rate of 30% when they were stored in the dark for 12 h. This result shows that the layered TiO₂/ITO films acted as “electron pools” with an inherent energy storage capability. This unique property is attributable to the rougher surface and nearly porosity-free columnar structure, which is responsible for increased UV energy absorption and loss-free hole or electron transportation.     

Deposition of indium tin oxide by atmospheric pressure chemical vapour deposition

We report the deposition of indium tin oxide (ITO) by atmospheric pressure chemical vapour deposition (APCVD). This process is potentially scalable for high throughput, large area production. We utilised a previously unreported precursor combination; dimethylindium acetylacetonate, [Me₂In(acac)] and monobutyltintrichloride, MBTC.[Me₂In(acac)] is a volatile solid. It is more stable and easier to handle than traditional indium oxide precursors such as pyrophoric trialkylindium compounds. Monobutyltintrichloride (MBTC) is also easily handled and can be readily vaporised. It is compatible with the process conditions required for using [Me₂In(acac)].Cubic ITO was deposited at a substrate temperature of 550 °C with growth rates exceeding 15 nm/s and growth efficiencies of between 20 and 30%. Resistivity was 3.5 × 10^− 4 Ω cm and transmission for a 200 nm film was > 85% with less than 2% haze.