Characteristics of SnO2 thin films prepared by SILAR

SnO₂ thin films were deposited on glass substrates by using Successive Ionic Layer Adsorption and Reaction (SILAR) method at room temperature. The film thickness effect on characteristic parameters such as structural, morphological, optical and electrical properties of the films was studied. Also, the films were annealed in oxygen atmosphere (400 °C, 30 min) and characteristic parameters of the films were investigated. The X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) studies showed that all the films exhibited polycrystalline nature with tetragonal structure and were covered well on glass substrates. After the investigation of the crystalline and surface properties of the films, it was found that they were improving with increasing film thickness. Optical band gap decreased from 3.90 eV to 3.54 eV and electrical conductivity changed between 0.015–0.815 (Ω-cm)⁻¹ as the film thickness increased from 215 to 490 nm. The refractive index (n), optical static and high frequency dielectric constants (ɛ_o, ɛ_∞) values were calculated by using the optical band gap values as a function of the film thickness.     

Electron injection dynamics of Ru polypyridyl complexes on SnO2 nanocrystalline thin films

Ultrafast infrared spectroscopy was utilized to investigate the electron-transfer dynamics from Ru(dcbpy)(2)(X)(2) complexes (dcbpy = 4,4'-dicarboxy-2,2'-bipyridine; X(2) = SCN(-), 2CN(-), and dcbpy; referenced as RuN3, Ru505, and Ru470, respectively) to nanocrystalline SnO(2) films. For both films exposed to air (dry) and submerged in a pH 2 buffer solution, all traces show biphasic dynamics with a small ultrafast component (less than 10%) and nonexponential slow component, indicating that most injection occurs from thermalized excited state of the dye. In the dry film, the injection rate becomes slower, comparing RuN3, Ru505, and Ru470, correlating with decreasing excited-state oxidation potentials in these dyes. However, the variation of injection rate with dye potential is less noticeable at pH 2. The possible reason for the different injection dynamics in these dyes and under different environments are discussed. These injection dynamics are also compared with those on TiO(2) and ZnO.     

SnO2 thin films prepared by dip-coating from microwave synthesized colloidal suspensions

Tin(IV) oxide thin films have been prepared by dip-coating. The suspensions used for these depositions have been synthesized by microwave-induced thermohydrolysis of tin tetrachloride aqueous solutions in the presence of hydrochloric acid. Single or multiple depositions were tested, on glass substrates as well as on pure SiO2. The obtained thin films were characterized by optical microscopy, interferometric roughness measurements (Micromap), scanning electron microscopy, secondary ion mass spectroscopy, and scanning tunneling microscopy.     

Electrodeposition of SnO2 nanocrystalline thin film using butyl-rhodamine B as a structure-directing agent

<正>Porous SnO_2 nanocrystalline thin films were successfully electrodeposited from an oxygen-saturated acid aqueous solution of SnCl_2 containing different concentrations of butyl-rhodamine B(BRhB) at 70℃.BRhB with substitute of amidocyanogen can be dissolved in the acid deposition solution,where HCl was added to suppress hydrolysis of SnCl_2.So it was used as a structure-directing agent to promote the crystal growth of SnO_2.The formed porous morphology and tetragonal rutile crystalline structure of the electrodeposited thin films were controlled by the addition of BRhB with different amounts.     

Preparation and characterization of CuAlO2 transparent thin films prepared by chemical solution deposition method

CuAlO₂ thin films were prepared on quartz glass and sapphire substrates by chemical solution deposition method using copper acetate monohydrate, aluminum nitrate nonahydrate and 2-methoxyethanol as starting precursor and solvent. The effects of annealing temperature on the structural, morphological, electrical and optical properties have been studied. Via the optimized annealing treatment condition, CuAlO₂ film annealed at 850 °C in nitrogen flow of 400sccm under atmosphere pressure exhibits the best performance with the lowest room temperature resistivity of 3.6 × 10² Ω cm and the highest optical transmission in the visible region (>70% at around 600 nm wavelength). CuAl₂O₄ and CuO phases, not CuAlO₂ phase are obtained when annealing temperature is lower than 850 °C. However, a further increase of annealing temperature weakens the crystallization quality and deteriorates the surface morphology of CuAlO₂ films as the annealing temperature exceeds 850 °C, leading to an increase in the resistivity and a decrease of the optical transmission in the visible region of CuAlO₂ films.     

Anatase TiO2 porous thin films prepared by sol-gel method using CTAB surfactant

Anatase TiO₂ porous thin films were prepared on glass substrates by sol-gel method with Cetyltrimethylammonium Bromide (CTAB) as a pore-forming agent, Tetrabutylorthotitanate as Ti precursor, ethanol as solvent and diethanolamine as chelating agent respectively. IR, TG-DSC, XRD and SEM analyzed the chemical and physical changes during sol-gel process and characteristics of the films. Effects of the amount of CTAB, alkane and water on morphology of the films were discussed and the principle of forming porous structure was proposed. It was shown that the diameter of pores was changed in the range of 30–400 nm.     

Synthesis and characterization of Mn:CdS nanoflower thin films prepared by hydrothermal method for photocatalytic activity

Journal of Sol-Gel Science and Technology - Mn-CdS nanoflowers were successfully deposited using hydrothermal technique at 150 °C for 2 h. The effect of changing the dopant...     

Electrical,optical, and structural characterization of p‐type N‐doped SnO thin films prepared by thermal oxidation of sputtered SnNx thin films

We present a study of electrical and optical properties of nitrogen‐doped tin oxide thin films deposited on glass by the DC Magnetron Sputtering method. The deposition conditions to obtain p‐type thin films were a relative partial pressure between 7% and 11% (N₂ and/or O₂), a total working pressure of 1.8 mTorr and a plasma power of 30 W. The deposited thin films were oxidized after annealing at 250°C for 30 minutes. X‐ray diffraction results showed that the as‐deposited thin films exhibit a Sn tetragonal structure, and after annealing, they showed SnO tetragonal structure. X‐ray photoelectron spectroscopy results showed the presence of nitrogen in the samples before and after annealing. The measured physical parameters of the thin films were optical band gap between 1.92 and 2.68 eV, resistivity between 0.52 and 5.46 Ωcm, a concentration of p‐type carriers between 10¹⁸ and 10¹⁹ cm^?3, and a Hall mobility between 0.1 and 1.94 cm²V^?1s^?1. These thin films were used to fabricate p‐type thin film transistors.     

The morphological,optical and electrical properties of SnO2:F thin films prepared by spray pyrolysis

Combining the spray pyrolysis and the sol–gel techniques gives the possibility to produce Fluorine doped Tin oxide (SnO₂:F) thin films. Transparent conducting SnO₂:F thin films have been deposited on glass substrates by the spray pyrolysis technique. This technique for the fabrication of SnO₂:F filmsby combining sol–gel process and the spray pyrolysis technique ispresented in this paper. The Sol–gel precursors have been successfully prepared using SnCl₂·5H₂O and (Ac)F₃. The structural, electrical, and optical properties of these films were investigated. The high resolution transmission electron microscopy (HRTEM) and selected area diffraction (SAD) patterns of SnO₂:F films show that the gel films lead to a tetragonal structure. The X‐ray diffraction pattern of the films deposited at substrate temperature 530° , the orientation of the films was predominantly [110]. In addition, the surface chemical components were also examined by X‐ray photoelectron spectroscopy (XPS) showing the SnO₂:F deposited with the atomic concentration ratios Sn/F 1.82:1. The minimum sheet resistance was 50 Ω and average transmission in the visible wavelength range of 300 to 800 nm was 87.25%. Copyright © 2008 John Wiley & Sons, Ltd.     

Fabrication and characterization of nanocrystalline cellulose films prepared under vacuum conditions

When dried under ambient conditions, the self-assembled chiral nematic arrangement of nanocrystalline cellulose (NCC) in suspension can be preserved in NCC films that can reflect light at specific wavelengths, but the process is slow. Rapid preparation of NCC films was first proposed to cast under vacuum conditions to accelerate water evaporation rates and shorten the drying time. Vacuum preparation of NCC films has been found to not only retain the self-assembled structure but to also increase the chiral nematic pitch and red-shift the reflection wavelength of the films. This method provides a new path to prepare NCC iridescent films with tunable reflection wavelengths and reduced time in many areas.     

Synthesis of TiO2 thin film by a modified sol-gel method and properties of the prepared films for photocatalyst

PTA (peroxo titanic acid) gel was prepared by a modified sol-gel method from peroxo titanic acid using TiCl₄/ethanol/water solution as the starting material at room temperature. Physicochemical properties of heat-treated gel were characterized by IR, XRD, TG-DTA and SEM. Optimal preparing conditions were chosen to prepare anatase film for the photocatalytic degradation of methyl orange. The dip-coating technique was used to synthesis the supported anatase film on quartz glass. Photocatalytic efficiency for the degradation of methyl orange under UV irradiation was also examined. It was found that the degradation efficiency of the anatase film synthesized in this paper is higher than commercial titania P25.     

Preparation and characterization of antimony-doped SnO2 thin films on gold and silver substrates for electrochemical and surface plasmon resonance studies

The paper reports on the deposition of thin antimony (Sb)-doped SnO₂ films onto gold and silver substrates using magnetron sputtering. The influence of the SnO₂:Sb film on the electrochemical and surface plasmon resonance properties is investigated. The best results in terms of stability, electrochemical and plasmonic characteristics are obtained for SnO₂:Sb of 8.5 nm thickness deposited on silver substrates.     

Synthesis of SiO2 thin films by sol-gel method using photoirradiation and molecular structure analysis

The SiO₂ thin films were prepared by a process which combines a sol-gel method and photoirradiation. The HF etch rate and microhardness of a film prepared by this process were better than those of a film furnace-fired at same temperature. The Raman and ²⁹Si solid state NMR spectra of film prepared by this process were similar to those of a film furnace-fired at higher temperature. There are many unstable folded non-linear SiO₂ species in the film prepared at low temperature. On treatment at higher temperature, unstable folded non-linear Si-O-Si rearranges to the stable linear Si-O-Si bond. Photoirradiation enhances this structure change. The process provided denser and harder SiO₂ thin films, even at low temperature, than the conventional furnace-firing method did.     

Physicochemical aspects of novel surfactantless, self-templated mesoporous SnO2 thin films

A novel method of synthesis consisting of the production of ordered arrangements of tubular pores distributed inside SnO2 annealed thin films, which are prepared from a rotating disk process carried out at 2000-3500 rpm, is herein described. The main novelty is that no surfactant molecules are required in order to create these ordered pore structures; the templating entities are supramolecular assemblies of oligomeric chains formed during the extra-long aging allowed to the sol-gel processing of tin(IV) tetra-tert-amiloxide, Sn(OAm(t))4, chelated with acetylacetone molecules. Low angle X-ray diffraction peaks of SnO2 thin films calcined at 500 degrees C clearly certify the existence of ordered mesostructures when employing the right H2O/Sn(OAm(t))4 molar ratio during the SnO2 sol-gel synthesis. The final SnO2 ordered mesostructures are reminiscent of those linked to MCM-41 and SBA-15 substrates. Pore-size distribution analyses proceeding from N2 sorption isotherms at 76 K on the SnO2 thin films calcined at 500 degrees C unequivocally confirm the presence of tubular mesopores (mode pore sizes ranging from 5 to 7 nm). The thicknesses of the SnO2 films range from 80 to 150 nm after performing a drying process at 100 degrees C and from 70 to 125 nm after calcining in air at 500 degrees C; these film thicknesses show, in general, decreasing trends when either the spinning rate or the H2O/(Sn(OAm(t))4 ratio is increased.     

Biological activity of functionalized SiO2 thin films prepared by sol-gel method

In this work we investigated the biological properties of sol-gel films in aqueous medium. Functionalized silica films were prepared by the sol-gel process, from organically modified silicon alkoxides with amino or thiol groups. Covalent binding of proteins with different orientations according to the hydrophilic or hydrophobic character of the surface was studied. This binding occurred via a covalent coupling agent providing a very stable linkage. No denaturation was detected and a good detection of the antigen was observed. Immunoassays have demonstrated the biological activity of grafted antibodies.     

Epitaxial ternary nitride thin films prepared by a chemical solution method

It is indispensable to use thin films for many technological applications. This is the first report of epitaxial growth of ternary nitride AMN2 films. Epitaxial tetragonal SrTiN2 films have been successfully prepared by a chemical solution approach, polymer-assisted deposition. The structural, electrical, and optical properties of the films are also investigated.     

Study of the properties of in situ Pt-doped SnO2 thin films prepared by metal-organic chemical vapour deposition

Pt-SnO₂ thin films were directly deposited by MOCVD in the temperature range 320–440°C using the reactive gas mixture SnEt4/O₂/Pt(hfa)₂ (hfa being bis(1,1,1,5,5,5-hexafluoroacetylacetonato). The Pt content of the films increases by increasing either the Pt(hfa)₂ mole fraction or the growth temperature. Platinum is uniformly incorporated through the thickness of the films although a small excess was found on the surface. In as-deposited films, Pt is in the metallic form on the surface whereas it is mainly in the form of PtO in the bulk of the layers. Pt doping decreases the resistivity by more than an order of magnitude and improves the thermal stability of the films. The detection sensitivity to ethanol in dry air of in situ Pt-doped SnO₂ is significantly enhanced compared to undoped layers. Another beneficial effect of Pt doping is the lowering of the optimum detection temperature of ethanol.     

Comparison characterization of copper selenide thin layers prepared on polyamide 6 films by sorption-diffusion method

Some earlier synthesized copper selenide (Cu _x Se) layers formed on the surface of polyamide 6 by sorption-diffusion method using potassium selenotrithionate (K₂SeS₂O₆) as precursor of selenium were characterized by the XRD, XPS and SEM methods. According to the results of the SEM studies, the most uniform Cu _x Se layers form at the 2.5 h polyamide seleniumized duration at the temperature of 60°C. The thickness of layers, which dependeds on the duration of seleniumization, changed in the range of 0.8–3.2 µm. The XRD patterns of not previously studied Cu _x Se layers showed their phase composition of six copper selenides: Cu₂Se, two phases of CuSe₂, Cu₃Se₂, berzellianite, Cu_2-x Se, and bellidoite Cu₂Se. Analysis of the XRD and XPS data shows that the macrostructure and composition of the Cu_xSe layers depend on the conditions of formation of these layers.