Ellipsometry study of poly(o-methoxyaniline) thin films

Spin-coated poly(o-methoxyaniline) (POMA) thin films on various substrates were investigated using spectroscopic ellipsometry (SE) in the 1.5–4.5 eV photon energy range. Spin-coating process parameters are reported (spin speed and concentration). Substrates with higher surface energy were found to increase polymer film thickness and decrease roughness. An optical model was developed using SE data along with complementary data from atomic force microscopy and UV–vis spectroscopy to obtain optical properties—refractive index n and extinction coefficient k for POMA. The model includes Lorentz oscillators for the POMA film and a Bruggeman effective medium approximation for roughness. In-plane film optical anisotropy was not observed, but a small out of plane anisotropy was detected for the polymer.     

Surface morphology control of zirconia thin films prepared using novel photochromic molecules

A new photochromic ZrO₂ precursor solution was prepared using zirconium tetra-n-butoxide, 4-(phenylazo)benzoic acid and ethyleneglycol monomethylether. The density functional theory (DFT) calculation has identified that the structure of the synthesized precursor molecule changed by UV irradiation. Four types of thin films were prepared using the ZrO₂ precursor solution with and without UV irradiation and applying an electric field. It was found that the surface morphology of thin films changed by applying UV irradiation to the precursor solution and an electric field.     

Electrochemical deposition and characterization of cupric oxide thin films

Polycrystalline cupric oxide (CuO) thin films are deposited using an alkaline solution bath employing cathodic electrodeposition method. Thin films are electroplated at various bath temperatures onto conducting indium tin oxide coated glass substrates. The bath temperature effects on the structural, optical and morphological properties of copper oxide films are studied and reported. X-ray diffraction studies revealed mixed phases of monoclinic and cubic for films grown at lower bath temperatures and that the deposited films at temperatures optimized as 75 °C exhibited cubic structure with preferential orientation along a (111) plane. Texture coefficient (T_c) values are calculated for all diffraction lines and the films were highly textured (T_c > 1). The surface morphology and surface roughness are estimated using scanning electron microscopy and atomic force microscopy, respectively and a morphology made up of pyramid shaped grains is presented. Energy dispersive analysis by X-rays revealed that the near stoichiometric CuO thin films are obtained at optimized preparative parameters. The refractive index is calculated using the envelop method. Also, the optical constants of CuO thin films such as complex dielectric constant (ε) and extinction coefficient (k) are also evaluated and reported.     

Microstructure and optical properties of plasmapolymer thin films with embedded silver nanoparticles

Plasmapolymer thin films with embedded silver nanoparticles were deposited by simultaneous plasma polymerization and metal evaporation. The particle size and shape were determined by transmission electron microscopy (TEM) and analysed by optical image processing. The optical properties in the UV/ VIS/NIR spectral region were determined by the plasma resonance absorption of the silver particles. Transmittance spectra were calculated with the Bergman effective medium theory and compared with experimental spectra.     

Waveguide-modulated surface plasmon-coupled emission of Nile blue in poly(vinyl alcohol) thin films

Surface plasmon-coupled emission (SPCE) phenomenon is the coupling of excited fluorophores near a silver film with surface plasmons, resulting in directional emission into the underlying glass substrates. We report a complex coupling of Nile Blue fluorophore with 50 nm silver mirror, resulting in emission at several angles in the glass substrate, with either s or p polarization. This complex pattern of directional and polarized emission appears to be due to optical waveguide effects occurring when the sample thickness becomes comparable to the emission wavelength. We expect waveguide-modulated SPCE to have applications to biophysics and sensing.     

Modulated IR radiometry of (TiSi)N thin films

The thermal properties of (TiSi)N thin films deposited by dc reactive magnetron sputtering on steel have been measured using contactless modulated IR radiometry. To interpret the measured IR signals, a two-layer model has been applied, and to describe surface roughness effects related to the coatings' growth process, a three-layer model has been developed. Empirical correlations have been found between thermal transport properties and structural-physical parameters, e.g. the grain size and surface roughness of the coatings, and first correlations have additionally been found with the deposition conditions, e.g. the bias voltage.     

Intrinsic optical and structural properties of SrS thin films

SrS thin films were deposited by electron beam evaporation on heated silica substrates. The optical properties of the layers – complex refractive index and optical band gap –were derived from optical transmission spectra, measured by means of UV-VIS-NIR spectrophotometry. The influence of post-deposition annealing by rapid thermal processing (RTP) was studied. X-ray powder diffraction (XRD) was used to study the film crystal structure and preferential orientation.     

Stochastic homogenization of nano-thickness thin films including patterned holes using structural perturbation method

The aim of this paper is to investigate the statistical response of the homogenized mechanical behavior of nano-thickness thin films with circular holes. For this purpose, a stochastic multiscale framework is proposed. The proposed framework involves molecular dynamics simulation, surface modeling, asymptotic homogenization, moving-mesh technique, Monte-Carlo simulation, and a reduced computational scheme. The surface effect of thin-film material is predicted by the molecular dynamics (MD) approach. The volume fraction and location of each circular hole are considered as geometric uncertainties of a model. In order to investigate the statistical response of the homogenized mechanical behavior, Monte-Carlo simulation is performed to show the probability density distribution of the homogenized elastic modulus against geometric uncertainties. The reduced computational schematic based on the static reduction method and the structural perturbation method is proposed in order to overcome the issues of a cumbersome remeshing procedure and computational inefficiency of Monte-Carlo simulations involving a high number of repetitive trials. A guideline to minimize the coefficient of variation (CV) of the mechanical properties is suggested based on the parametric study.     

高性能导电薄膜的制备

采用磁控溅射法在玻璃基底上制备了Cr-Cu-Al-Cr薄膜,用焊接法测试薄膜附着性能,用x射线衍射仪（XRD）、原子力显微镜（AFM）和台阶仪对薄膜进行表征,研究溅射过程中以及在高温大气环境下薄膜的防氧化方法,分析薄膜晶粒大小与电性能关系,制备出性能较好的导电膜。     

Sol-gel synthesis of nickel oxide thin films and their characterization

Sol-gel method has been employed for the synthesis of nanocrystalline nickel oxide (NiO). The NiO powders were sintered at 400-700 °C for 1 h in an air. Thin films of sintered powders were prepared on glass substrate using spin coating technique and changes in the structural, morphological, electrical and optical properties were studied. The structural and microstructural properties of nickel oxide films were studied by means of X-ray diffraction and field emission scanning electron microscopy. Structural analysis shows that all the films are crystallized in the cubic phase and present a random orientation. Surface morphology of the nickel oxide film consists of nanocrystalline grains with uniform coverage of the substrate surface with randomly oriented morphology. The electrical conductivity showed the semiconducting nature with room temperature electrical conductivity increased from 10^− 4 to 10^− 2 (Ω cm) ^− 1 after sintering. The electron carrier concentration (n) and mobility (μ) of NiO films annealed at 400-700 °C were estimated to be of the order of 1.30 to 3.75 × 10¹⁹ cm^− 3 and 1.98 to 4.20 × 10^− 5 cm² V^− 1 s^− 1.The decrease in the band gap energy from 3.86 to 3.47 eV was observed for NiO sintered between 400 and 700 °C. These mean that the optical quality of NiO films is improved by sintering.     

Electrical and physicochemical properties of Poly(3,4-ethylenedioxythiophene)-based organic-inorganic hybrid conductive thin films

Conductive polymer coating precursors were prepared using poly (3, 4-ehtylenedioxythiophene) (PEDOT) and three kinds of silane precursors (Q type, T type, and bridged T type) through an in-situ organic/inorganic hybrid sol-gel process. The spin-coated precursor films on Poly(ethyleneterephthalate) substrate exhibited fairly good surface resistance (~ 10⁴ Ω/□), transparency (~ 80%) and pencil hardness (2 - 4 H). The solvent resistance of the film using 2, 5-bis (triethoxysilyl)-3, 4-ethylenedioxythiophene (BTES-EDOT) was excellent as compared with the films that used silane precursors due to a high degree of BTES-EDOT crosslinking in the hybrid film. Moreover, EDOT moiety in the BTES-EDOT molecule may contribute to homogeneous dispersion of the PEDOT in the organic-inorganic hybrid film.     

Preparation and characterization of amorphous manganese sulfide thin films by SILAR method

Manganese sulfide thin films were deposited by a simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method using manganese acetate as a manganese and sodium sulfide as sulfide ion sources, respectively. Manganese sulfide films were characterized for their structural, surface morphological and optical properties by means of X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and optical absorption measurement techniques. The as-deposited film on glass substrate was amorphous. The optical band gap of the film was found to be thickness dependent. As thickness increases optical band gap was found to be increase. The water angle contact was found to be 34°, suggesting hydrophilic nature of manganese sulfide thin films. The presence of Mn and S in thin film was confirmed by energy dispersive X-ray analysis.     

Preparation and optical characterization of lanthanum modified lead zirconate titanate thin films on indium-doped tin oxide-coated glass substrate

Lanthanum modified lead zirconate titanate (PLZT) thin films were fabricated on indium-doped tin oxide (ITO)-coated glass substrate by sol-gel method. The structure of the films was characterized with X-ray diffraction and scanning electron microscopy. The optical properties were investigated in the wavelength range of 220-2400 nm. The sample was modelled as a three layer structure on finite substrate, and optical constants of this system were calculated from the transmission and reflection spectra. The calculated dielectric function was fitted with the Drude model in the case of ITO and a sum of Lorentzian oscillators in the case of PLZT films. For PLZT film the anomalous behaviour of imaginary part of dielectric function was observed below the absorption edge. The possible reasons of that behaviour were discussed.     

Structural and dielectric properties of (001) and (111)-oriented BaZr0.2Ti0.8O3 epitaxial thin films

We have grown and characterized BaZr_0.2Ti_0.8O₃ (BZT) epitaxial thin films deposited on (001) and (111)-oriented SrRuO₃-buffered SrTiO₃ substrates by pulsed laser deposition. Structural and morphological characterizations were performed using X-ray diffractometry and atomic force microscopy, respectively. A cube-on-cube epitaxial relationship was ascertained from the θ-2θ and φ diffractograms in both (001) and (111)-oriented films. The (001)-oriented films showed a smooth granular morphology, whereas the faceted pyramid-like crystallites of the (111)-oriented films led to a rough surface. The dielectric response of BZT at room temperature was measured along the growth direction. The films were found to be ferroelectric, although a well-saturated hysteresis loop was obtained only for the (001)-oriented films. High leakage currents were observed for the (111) orientation, likely associated to charge transport along the boundaries of its crystallites. The remanent polarization, coercive field, dielectric constant, and relative change of dielectric permittivity (tunability) of (111)-oriented BZT were higher than those of (001)-oriented BZT.     

Chemical bath deposition of indium sulphide thin films: preparation and characterization

Indium sulphide (In₂S₃) thin films have been successfully deposited on different substrates under varying deposition conditions using chemical bath deposition technique. The deposition mechanism of In₂S₃ thin films from thioacetamide deposition bath has been proposed. Films have been characterized with respect to their crystalline structure, composition, optical and electrical properties by means of X-ray diffraction, TEM, EDAX, optical absorption, TRMC (time resolved microwave conductivity) and RBS. Films on glass substrates were amorphous and on FTO (flourine doped tin oxide coated) glass substrates were polycrystalline ( phase). The optical band gap of In₂S₃ thin film was estimated to be 2.75 eV. The as-deposited films were photoactive as evidenced by TRMC studies. The presence of oxygen in the film was detected by RBS analysis.     

Deposition and modification of titanium dioxide thin films by filtered arc deposition

Thin films of titanium dioxide have been deposited on glass substrates and conducting (100) silicon wafers by filtered arc deposition (FAD). The influence of the depositing Ti⁻ energy, substrate types and substrate temperature on the structure, density, mechanical and optical properties have been investigated. The results of X-ray diffraction (XRD) showed that with increasing substrate bias, the film structure on silicon substrates changes from anatase to amorphous and then to rutile phase without auxiliary heating, the transition to rutile occurring at a depositing particle energy of about 100 eV. However, in the case of the glass substrate, no changes in the structure and optical properties were observed with increasing substrate bias. The optical properties over the range of 300–800 nm were measured using spectroscopic elliosometery, and found to be strongly dependent on the substrate bias, film density and substrate type. The refractive index values of the amorphous, anatase and rutile films on Si were found to be 2.56, 2.62 and 2.72 at a wavelength of 550 nm, respectively. The hardness and elastic modulus of the films were found to be strongly dependent on the film density. Measurements of the mechanical properties and stress also confirmed the structural transitions. The hardness and elastic modulus range of TiO₂ films were found to be between 10–18 and 140–225 GPa, respectively. The compressive stress was found to vary from 0.7 to 2.6 GPa over the substrate bias range studied. The composition of the film was measured to be stoichiometric and no change was observed with increasing substrate bias. The density of the film varied with change in the substrate bias, and the density ranged between 3.62 and 4.09 g/cm³.     

An electrochemical technique to deposit thin films of PbTe

PbTe thin films were deposited electrochemically on transparent conducting oxide coated (TCO) glass substrates from a solution of lead acetate and TeO₂ at low pH. A lead (Pb) strip was used as a sacrificing anode and the TCO glass acted as the cathode, which were short-circuited externally. Depositions were carried out at different temperatures of the bath to study the growth kinetics and grain growth. X-ray diffraction technique, scanning electron microscopy, infrared spectroscopy and resistivity measurements were carried out to characterize the deposited films. The films were polycrystalline in nature with a cubic phase.     

改性石墨烯/聚(偏二氟乙烯-共-六氟丙烯)复合材料薄膜的制备与性能

采用改进Hummers法对天然鳞片石墨进行氧化和超声剥离处理制备氧化石墨烯（GO）,将十三氟辛基三乙氧基硅烷（FAS）与GO反应并还原得到FAS修饰的还原氧化石墨烯（FAS-RGO）。利用溶液涂覆成膜工艺制得FAS-RGO/聚（偏二氟乙烯-共-六氟丙烯）（P（VDF-HFP））复合材料。采用FTIR、XPS、XRD、Raman和TEM表征了FAS-RGO的结构与形貌,同时研究了FAS-RGO用量对FAS-RGO/P（VDF-HFP）介电性能的影响。结果表明：FAS包覆在RGO的表面,有效解决了RGO容易团聚的问题,并且FAS的引入提高了RGO与P（VDF-HFP）的界面结合,改善了RGO在P（VDF-HFP）中的分散性,FAS-RGO还能提高P（VDF-HFP）的结晶性,促进形成β晶型。当FAS-RGO的体积分数为1.6vol%、在100 Hz频率时,FAS-RGO/P（VDF-HFP）复合材料的介电常数为62,较纯P（VDF-HFP）提高了5.2倍,同时FAS-RGO/P（VDF-HFP）复合材料的介电损耗较低。     

Controlled formation of Ag/poly(methyl-methacrylate) thin films by RAFT technique for optical switcher

The functional group of sulfur was introduced into the PMMA terminus by the reversible addition-fragmentation transfer (RAFT) technique and the PMMA/Ag nanocomposite film was prepared by the in situ synthetic method. The third-order nonlinear optical properties of the material were further investigated by the Z-scan technique. The result shows that the χ⁽³⁾ nonlinearity of the material depend on the doped content of Ag nanoparticles and is obtained to be 6.22 × 10⁻⁹ esu at the content of 2.4 wt%. Furthermore, it is found that the material has the potential application on optical switcher at the content of 0.8 wt%.     

Preparation of high quality spray-deposited fluorine-doped tin oxide thin films using dilute di(n-butyl)tin(iv) diacetate precursor solutions

Fluorine-doped tin oxide (FTO) thin films were prepared, at different substrate temperatures, using dilute precursor solutions of di(n-butyl)tin(iv) diacetate (0.1 M DBTDA) by varying the F⁻ concentration in the solution. It is noticed that conductivity of FTO film is increasing by increasing the fluorine amount in the solution. Morphology of SEM image reveals that grain size and its distribution are totally affected by the substrate temperature in which conductivity is altered. Among these FTO films, the best film obtained gives an electronic conductivity of 31.85 × 10² Ω^− 1 cm^− 1, sheet resistance of 4.4 Ω/□ (ρ = 3.14 × 10^− 4 Ω cm) with over 80% average normal transmittance between the 400 and 800 nm wavelength range. The best FTO film consists of a large distribution of grain sizes from 50 nm to 400 nm range and the optimum conditions used are 0.1 M DBTDA, 0.3 M ammonium fluoride, in a mixture of propan-2-ol and water, at 470 °C substrate temperature. The large distribution of grain sizes can be easily obtained using low DBTDA concentration (~ 0.1 M or less) and moderate substrate temperature (470 °C).