Substrate temperature effects on the tin oxide films prepared by spray pyrolysis

Indium-doped tin oxide films were prepared by the spray pyrolysis technique at different substrate temperatures ranging from 400–525 C. Texture coefficients for (200) and (112) reflections of tetragonal SnO₂ were calculated. The surface morphology of the prepared films was revealed by using scanning electron microscopy. A dendrite structure was observed in the films deposited at a substrate temperature of 525 C. The obtained specific resistances were correlated with those obtained from X-ray diffraction analysis and scanning electron microscopy. A study of the effect of film thickness on the plane of preferred orientation was carried out.     

Single step synthesis of indium tin oxide by ultrasonic spray and microwave assisted pyrolysis

Ultrafine indium tin oxide (ITO) powders were successfully synthesised by the combined methods of ultrasonic spray and microwave assisted pyrolysis, which is a single step, facile, rapid and continuous method without post-heating treatment. Crystallinity, morphology and microstructure of the samples were investigated by X-ray diffractometer, scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectroscope, selected area electron diffraction pattern and laser grain size analyser. Results indicate that pure solid solution ITO ultrafine powders with homogeneous and narrow size distribution, highly dense and smooth surface morphology can be obtained under optimum conditions. Each uniform spherical particle consisted of many smaller crystallites with diameter of <10 nm.     

Synthesis of indium tin oxide powder by solid-phase reaction with microwave heating

Indium tin oxide (ITO) powder was synthesized from indium oxide and tin oxide powders by a solid-phase method using microwave heating and conventional heating methods. Microwave heating could reduce the treatment time necessary for the completion of the solid-phase reaction by 1/30. This decrease was attributed to an increase in the diffusion rate of Sn at the local heat spot in the indium oxide formed by microwave irradiation. However, microwave heating also decreased the amount of ITO produced, since the powder layer of the raw material was heated unevenly and had an uneven temperature distribution.Therefore, a microwave heating method including a mixing process was proposed in order to diminish the uneven progress of the ITO synthesis reaction in the powder layer. This revised method could increase the conversion to ITO, which is higher than that obtained by using the conventional heating method. Hence, the electric conductivity of the powder layer obtained by the proposed method was higher than that of the commercially supplied ITO powder layer.     

Characterization of molybdenum-doped indium oxide thin films by spray pyrolysis technique

In this research, indium oxide nanostructure undoped and doped with Mo were prepared on glass substrates using spray pyrolysis technique. Various parameters such as dopant concentration and deposition temperatures were studied. Structural properties of these films were investigated by X-ray diffraction and scanning electron microscopy. Electrical and optical properties have been studied by Hall effect and UV–Visible spectrophotometer, respectively. The thickness of the films was determined by PUMA software. The variation of refractive index, extension coefficient and bandgap of these films also were investigated.     

Gas sensitivity of metal oxide mixed tin oxide films prepared by spray pyrolysis

Various kinds of SnO₂ films, modified with the addition of iron, antimony, copper, titanium, manganese, nickel, cobalt or calcium oxides, were fabricated by using the spray pyrolysis technique and their gas-sensing characteristics were studied. From electrical measurements in air, the relative sensitivity towards inflammable gas of these SnO₂-based film sensors was compared. It was observed that SnO₂-based films of higher electrical resistance had a tendency to have higher sensitivity towards ethanol than the SnO₂-based films of lower resistance. The addition of p-type metal oxides, such as NiO and MnO, to the SnO₂ matrix was found to be effective in increasing the sensitivity towards inflammable gas.     

In-situ fabrication of nanostructured cobalt oxide powders by spray pyrolysis technique

Nano-crystalline Co3O4 and CoO powders have been prepared by a spray pyrolysis approach. The effects of the reaction temperature and initial salts on the crystallinity and phase composition have been studied. Based on the TEM and XRD results, the crystal sizes were in the range of 1-10 nm. SEM and TEM observations also reveal that the nano-powders easily create micron-scale spherical agglomerates. The Co3O4 powders obtained by spraying nitrate solution at 500 degrees C show high specific surface area, which according to the BET method is 82.37 m2/g. The time/temperature phase diagram of cobalt oxides developed from XRD and DTA/TGA analyses shows the existence of a CoO phase at low and high temperature ranges when some specific preparation conditions are applied.     

喷雾热分解法制备SnO2·F薄膜与导电性能研究

以SnCl4·5H2O和NH4F为原料,采用喷雾热分解的方法在片状日用玻璃基材和石英玻璃基材上制得了掺氟氧化锡透明导电薄膜.采用X射线衍射仪(XRD)和扫描电镜(SEM)分别对薄膜的内部结构和表面形貌进行了表征.研究了F-的掺杂量、喷涂温度、沉积时间和热处理对薄膜方阻R□的影响.实验结果表明,当[NH4F]/[SnCl4·5H2O]=32wt%、成膜温度为450℃、喷涂时间为15s时,可使所得薄膜的方阻R□达最低,为10Ω/□.     

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.     

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.     

Deposition of improved optically selective conductive tin oxide films by spray pyrolysis

Antimony-doped SnO₂ films with a resistivity as low as 9×10^–4 cm were prepared by spray pyrolysis. Structural, electrical and optical properties were studied by varying the antimony concentration, film thickness and deposition temperature. About 94% average transmission in the visible region and about 87% infrared reflectance were obtained for antimony-doped SnO₂ films by a systematic optimization of the preparation parameters. As the best combination, an average transmission of 88% in the visible region and an infrared reflectance of 76% was possible for the doped SnO₂ films.     

Temperature dependence of Fluorine-doped tin oxide films produced by ultrasonic spray pyrolysis

Fluorine-doped tin oxide (FTO) films were prepared at different substrate temperatures by ultrasonic spray pyrolysis technique on glass substrates. Among F-doped tin oxide films, the lowest resistivitiy was found to be 6.2 × 10^− 4 Ω-cm for a doping percentage of 50 mol% of fluorine in 0.5 M solution, deposited at 400 °C. Hall coefficient analyses and secondary ion mass spectrometry (SIMS) measured the electron carrier concentration that varies from 3.52 × 10²⁰ cm^− 3 to 6.21 × 10²⁰ cm^− 3 with increasing fluorine content from 4.6 × 10²⁰ cm^− 3 to 7.2 × 10²⁰ cm^− 3 in FTO films deposited on various temperatures. Deposition temperature on FTO films has been optimized for achieving a minimum resistivity and maximum optical transmittance.     

Effect of indium doping on zinc oxide films prepared by chemical spray pyrolysis technique

We report the conducting and transparent In doped ZnO films fabricated by a homemade chemical spray pyrolysis system (CSPT). The effect of In concentration on the structural, morphological, electrical and optical properties have been studied. These films are found to show (0 0 2) preferential growth at low indium concentrations. An increase in In concentration causes a decrease in crystalline quality of films as confirmed by X-ray diffraction technique which leads to the introduction of defects in ZnO. Indium doping also significantly increased the electron concentrations, making the films heavily n type. However, the crystallinity and surface roughness of the films decreases with increase in indium doping content likely as a result of the formation of smaller grain size, which is clearly displayed in AFM images. Typical optical transmittance values in the order of (80%) were obtained for all films. The lowest resistivity value of 0.045 Ω-m was obtained for film with 5% indium doping.     

Studies on tin oxide films prepared by electron beam evaporation and spray pyrolysis methods

Transparent conducting tin oxide thin films have been prepared by electron beam evaporation and spray pyrolysis methods. Structural, optical and electrical properties were studied under different preparation conditions like substrate temperature, solution flow rate and rate of deposition. Resistivity of undoped evaporated films varied from 2.65 × 10⁻² ω-cm to 3.57 × 10⁻³ ω-cm in the temperature range 150–200°C. For undoped spray pyrolyzed films, the resistivity was observed to be in the range 1.2 × 10⁻¹ to 1.69 × 10⁻² ω-cm in the temperature range 250–370° C. Hall effect measurements indicated that the mobility as well as carrier concentration of evaporated films were greater than that of spray deposited films. The lowest resistivity for antimony doped tin oxide film was found to be 7.74 × 10⁻⁴ ω-cm, which was deposited at 350°C with 0.26 g of SbCl₃ and 4 g of SnCl₄ (SbCl₃/SnCl₄ = 0.065). Evaporated films were found to be amorphous in the temperature range up to 200°C, whereas spray pyrolyzed films prepared at substrate temperature of 300– 370°C were poly crystalline. The morphology of tin oxide films was studied using SEM.     

喷雾热解法制备掺氟氧化锡导电玻璃及其性能

采用喷雾热解法,以四氯化锡和氟化铵为原料、喷瓶为雾化装置,在载玻片上制得氟掺杂二氧化锡(FTO)透明导电薄膜。运用XRD、SEM、紫外-可见分光光度计和四探针测试仪分别对薄膜进行了表征。研究了喷涂次数、衬底温度、前体浓度、掺杂浓度和醇水比对FTO薄膜光电性能的影响。结果表明,当衬底温度为500℃,SnCl4.5H2O浓度为0.81mol/L,NH4F浓度为0.1mol/L,醇水比为8:2,喷涂100次时,薄膜的光电性能较好,其方块电阻为13Ω/□,平均透光率为79%。     

水热法合成铟锡氧化物纳米粒子的制备及表征

采用三氧化二铟和真空蒸发法制得的纳米锡粉为原料，溶解在一定浓度的氢氧化钠溶液中，水热条件下成功的合成了纳米级的铟锡氧化物粒子，通过粉末X射线衍射（XRD），场发射扫描电子显微镜（FE-SEM），透射电子显微镜（TEM）和紫外可见光光吸收光谱（Uv-Vis）等手段对所得产物进行表征。讨论了反应时间、pH值因素对产物成分和形貌的影响。结果表明：在温度为180℃，10mol／L NaOH溶液的条件下，水热反应36h得到比较均一的产物In1.94Sn0.06O3，产物形貌为均匀的六面体，大小在100nm左右，且对波长在200-400nm的光有强烈的吸收。     

Immobilization of aromatic aldehyde molecules on indium tin oxide surface using acetalization reaction

We demonstrated an acetalization reaction as a versatile method to immobilize aromatic aldehyde molecules on surfaces of metal oxides, silicon dioxide, and indium tin oxide. First, a trimethylsily (TMS) terminated surface was formed using a silylation reaction between a chloride group of trimethylsilychloride and a hydroxyl group of the substrate surfaces. Second, terephthalaldehyde (TPA) was immobilized on the surfaces using an acetalization reaction between the TMS-terminated surface and an aldehyde group of TPA. Results of contact angle, X-ray photoelectron, and ultraviolet absorption spectra revealed that the TPA molecules on the surfaces were well-packed with a high surface density.     

Nano-sized manganese oxide particles prepared by low-pressure spray pyrolysis using FEAG process

Nano-sized manganese oxide particles were prepared by low-pressure spray pyrolysis using the new type of liquid aerosol generator called as FEAG process. The particles prepared from polymeric precursors spray solution with organic additives had large size, hollow and fractured morphologies due to the gas evolution from the decomposition of the organic additives. The precursor particles with micron size, hollow and thin wall structures turned to nano-sized manganese oxide particles after post-treatment at temperatures of 700 and 800 °C. The optimum concentrations of citric acid (CA) and ethylene glycol (EG) to prepare the nano-sized manganese oxide particles by spray pyrolysis using the FEAG process were 0.3 M each. The manganese oxide particles prepared from the polymeric precursors spray solutions with high concentrations of CA and EG had spherical shape and porous morphologies.     

Influence of manufacturing process of indium tin oxide sputtering targets on sputtering behavior

Thin films of In₂O₃+SnO₂ (indium tin oxide or ITO) have wide utility because they are electrically conductive and transparent at visible wavelengths. A preferred method for making highest quality ITO coatings is reactive sputtering from targets of mixed indium and tin oxides. The resulting film properties are highly dependent upon the deposition conditions, and upon post-deposition film treatments. Film data and sputtering efficiency are also effected by sputtering target characteristics.

This study evaluated the influence of the targets on the electrical resistivity of deposited ITO films, and the effect of target properties on the sputtering rate. A matrix of 12 targets was tested; all had composition 90 wt.%In₂O₃+10 wt.%SnO₂. The effects of varying target density, degree of target oxide reduction from complete stoichiometry, and target purity were measured.

The results are, in summary, (1) partial reduction of oxide targets from complete stoichiometry does not influence film resistivity, (2) the data indicate a small (perhaps negligible) dependence of film resistivity upon target density, (3) higher target density tends to promote enhanced deposition rate, and (4) purposeful addition of silicon, aluminum, magnesium, calcium, and sodium at high levels to ITO targets degrades film resistivity depending upon the total concentration of impurities added, but independently of the contaminating species.     

The production of ultrafine zirconium oxide powders by spray pyrolysis

Twin-fluid atomisation spray-pyrolysis has been investigated for the production of ZrO₂ powders. The atomiser used in this study has a novel internal arrangement that can produce a spray with a mean diameter (SMD) of less than 5 m. Spray pyrolysis tests with zirconium nitrate as a precursor salt were performed and the formation of ZrO₂ powder was studied under substantially different heating rates and initial solution concentrations. A mean particle diameter, d(0.5), of 0.67 m and 0.77 m was achieved for 0.05 M and 0.5 M solutions, respectively. It was concluded that the new nozzle design performed well and was successful in producing ultra-fine ZrO₂ powder with a principally tetragonal structure when the correct process conditions of heating rate and residence time were applied.     

Preparation of transparent conductive indium tin oxide thin films from nanocrystalline indium tin hydroxide by dip-coating method

Indium tin oxide (ITO) thin films with well-controlled layer thickness were produced by dip-coating method. The ITO was synthesized by a sol-gel technique involving the use of aqueous InCl₃, SnCl₄ and NH₃ solutions. To obtain stable sols for thin film preparation, as-prepared Sn-doped indium hydroxide was dialyzed, aged, and dispersed in ethanol. Polyvinylpyrrolidone (PVP) was applied to enhance the stability of the resulting ethanolic sols. The transparent, conductive ITO films on glass substrates were characterized by X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy. The ITO layer thickness increased linearly during the dipping cycles, which permits excellent controllability of the film thickness in the range ~ 40-1160 nm. After calcination at 550 °C, the initial indium tin hydroxide films were transformed completely to nanocrystalline ITO with cubic and rhombohedral structure. The effects of PVP on the optical, morphological and electrical properties of ITO are discussed.