Study on the properties of a nanocrystal and polymer composite PbTiO3/PEK-c film with optical anisotropy

Composite thin films of PbTiO₃ nanocrystals and PEK-c polymer for applications in nonlinear optical devices were prepared by spin coating. The size of PbTiO₃ nanocrystals was estimated to be 30–40 nm. The microstructure of PbTiO₃/PEK-c composite polymer film before and after poling was analyzed by X-ray diffraction, which show that this film is c axis-orientated. The poled composite film displayed the refractive index anisotropy. In this sample the TE- and TM-indices differences are found to be 0.02945 for 633 nm and 0.03915 for 414 nm. The electro-optic coefficient ₃₃ of poled composite film was measured to be 12.89 pm V^–1 at 633 nm by the transmission technique. The dielectric constant of it at 100 KHz under room temperature was determined to be 7.32. The figure of merit F ₂ was estimated to be 492. In addition, a relaxation process was observed in the time range of 28 days and the relaxation time constant was calculated to be 2393 min.     

Optical waveguiding in epitaxial PbTiO(3) thin films

Epitaxial lead titanate (PbTiO(3)) thin films on SrTiO(3) (100) substrate were grown in situ by radio-frequency sputtering for optical waveguiding applications. The crystalline quality of the PbTiO(3) films deposited at 550 degrees C has been investigated through x-ray diffraction analysis. It indicates that thin films are completely c-axis oriented (rocking curve FWHM of 0.2 degrees for the 001 reflection). The transmission spectrum method has been used to measure the dispersion of the refractive index. At 632.8 nm, the PbTiO(3) film with an (001) orientation exhibits a refractive index of 2.61, which represents 98% of the bulk material. The prism-coupling technique has been also employed to determine the optical attenuation in the planar waveguide. In this study, we report a low propagation loss of 2.2 ? 0.2 dB/cm obtained in a PbTiO(3) optical waveguide.     

Inkjet printing of multi-walled carbon nanotube/polymer composite thin film for interconnection

In this paper, multi-walled carbon nanotube (MWCNT) ink was selectively patterned by inkjet printing on substrates to form conductive traces and electrodes for interconnection application. MWCNT was firstly functionalized using concentrated acid and dispersed in deionized water to form a colloidal solution. Various concentrations of MWCNT were formulated to test the stability of the solution. The printability of the MWCNT ink was examined against printing temperature, ink concentration and ink droplet pitch. Rheological properties of the ink were determined by rheometer and sessile drop method. The electrical conductivity of the MWCNT pattern was measured against multiple printing of MWCNT on the same pattern (up to 10 layers). While single layer printing pattern exhibited highest resistance, the CNT entangled together and formed a random network with more printed layers has higher conductivity. The electrical properties of the printed film was compared to a composite ink of CNT and conducting polymer (CNT ink was mixed with conductive polymer solution, Poly(3,4-ethylenedioxythiophene)-Poly(styrenesulfonate) (PEDOT:PSS)). Scanning electron microscopy (SEM) was used to observe the surface structure and atomic force microscopy (AFM) was used to study the morphology of the printed film under different conditions.     

Simultaneous determination of thickness and optical constants of polymer thin film by analyzing transmittance

We present a novel method for determining both the thickness and the optical constants of a weakly absorbing thin film upon a nearly transparent substrate through analysis of transmittance measured at various incident angles with coherent light. We demonstrate this method for a polymer thin film. The refractive indices and extinction coefficients of poly(DRI-anthranilic acid) at wavelengths of 1,064, 632.8, and 532 nm were determined for the first time to our knowledge. We also confirmed the validity of our method with a polystyrene thin film whose optical constant was known. It was found that a thickness of a few hundred nanometers can easily be measured and that this method offers simplicity as well as the capability of in situ measurement.     

Optical properties of the c-axis oriented LiNbO3 thin film

C-axis oriented Lithium Niobate (LiNbO₃) thin films have been deposited onto epitaxially matched (001) sapphire substrate using pulsed laser deposition technique. Structural and optical properties of the thin films have been studied using the X-ray diffraction (XRD) and UV-Visible spectroscopy respectively. Raman spectroscopy has been used to study the optical phonon modes and defects in the c-axis oriented LiNbO₃ thin films. XRD analysis indicates the presence of stress in the as-grown LiNbO₃ thin films and is attributed to the small lattice mismatch between LiNbO₃ and sapphire. Refractive index (n = 2.13 at 640 nm) of the (006) LiNbO₃ thin films was found to be slightly lower from the corresponding bulk value (n = 2.28). Various factors responsible for the deviation in the refractive index of (006) LiNbO₃ thin films from the corresponding bulk value are discussed and the deviation is mainly attributed to the lattice contraction due to the presence of stress in deposited film.     

Optical constants of thermally evaporated amorphous GeSe3 thin films

The optical transmission spectra of amorphous Ge-Se films of chemical composition GeSe₃, prepared by thermal evaporation, are measured overthe 300 nm to 2500 nm spectral region. A simple, straightforward procedure suggested by Swanepoel, which is based on the use of interference fringes, has been applied in order to derive the real and imaginary parts of the complex refractive index, and also the film thickness. Furthermore, thickness measurements made by a surface-profiling stylus are also carried out to cross-check the results obtained by the present optical method, employing only T(). The dispersion of n is discussed in terms of the single-oscillator Wemple and DiDomenico model, and the optical band gap E _g ^opt has been determined from the absorption coefficient values, using the Tauc procedure.     

Optical constants in the IR from thin film interference and reflectance: the reststrahlen region of muscovite mica

A new technique for determining the IR optical constants of materials that can be formed into thin films is presented. At a given wavelength the thickness of the film t, the index of refraction n, and the extinction coefficient k combine to produce interference effects in the film, which in turn control reflectance from the film. When reflectance is plotted vs thickness the resultant curve is a unique function of n and k. Values of n and k are determined by curve fitting. The technique is illustrated using thin films of muscovite mica, and values of n and k are reported for wave numbers from 1200 to 400 cm-1, which include the reststrahlen region of mica.     

Nonlinear optical properties and thermal stability of the poled polymer NTAB/PEK-c

Films of high glass transition temperature polymer polyetherketone doped with chromophore 2,2′-[4-[(5-nitro-2-thiazolyl)azophenyl]-amino]-bisethanol (NTAB) were prepared, poled by the corona-onset poling setup which includes a grid voltage making the surface-charge distribution uniform at elevated temperature. The thickness of the films was measured by the Model 2010 Prism Coupler system. Second harmonic generation d₃₃ was measured by the second harmonic generation method, and the d₃₃ is 38.12 pm/V at 1064 nm under the absorption correction. The nonlinear optical activity maintains 80% of its initial value.     

Deposition of PbTiO3 film by the spray-ICP technique

PbTiO₃ thin films were prepared on various substrates by spraying an ultrasonically atomized aqueous solution of Pb(NO₃)₂ + TiO (NO₃)₂ into an inductively coupled plasma (ICP) under atmospheric pressure. Single-phase PbTiO₃ with perovskite structure was obtained at 500–650 °C. The perovskite obtained below 600 °C showed less tetragonality due to the effect of grain size. The PbTiO₃ films crystallized with preferred (1 1 1) and (0 0 1) orientations on sapphire (0 0 1) and MgO (1 0 0), respectively. Based on the analysis of ICP emission spectra, it is suggested that a reoxidation of titanium preceded that of lead in the plasma, and also that OH in the plasma played an important role in the deposition of PbTiO₃.     

Optical constants of Zn-doped CuInS2 thin films

Optical properties of Zn-doped CuInS₂ thin films grown by double source thermal evaporation method have been studied. The amount of the Zn source was determined to be 0%-4% molecular weight compared with CuInS₂ source. After that, samples were annealed in vacuum at the temperature of 450 °C in quartz tube. The optical constants of the deposited films were obtained from the analysis of the experimental recorded transmission and reflexion spectral data over the wavelength range 300-1800 nm. It is observed that there is an increase in optical band gap with increasing Zn % molecular weight. It has been found that the refractive index and extinction coefficient are dependent on Zn incorporation. The complex dielectric constants of Zn-doped CuInS₂ films have been calculated in the investigated wavelength range. It was found that the refractive index dispersion data obeyed the single oscillator of the Wemple-DiDomenico model, from which the dispersion parameters and the high-frequency dielectric constant were determined. The electric free carrier susceptibility and the carrier concentration on the effective mass ratio were estimated according to the model of Spitzer and Fan.     

Development of guide rollers using electroplated carbon fiber-epoxy composite for thin polymer film processing

Since thin polymer films can not sustain the large tension generated from the rotational inertia of a guide roller during start and stop periods of film processing and can be easily damaged by the rough surface of the guide roller, the guide roller should have low rotational inertia, low friction coefficient, high bending stiffness and fine surfaces.

The carbon fiber-epoxy composite material electroplated with chromium has excellent properties for the structure of the guide roller due to its high specific modulus and high damping, which reduces induced vibrations.

In this paper, the design and manufacturing methods as well as the static, dynamic and frictional characteristics of the carbon fiber-epoxy composite rollers electroplated with chromium were investigated using analytical and experimental methods to improve the performance of the high speed guide roller.     

LaNiO3溅射薄膜的光学和电学特性的研究

采用LaNiO3陶瓷靶和射频磁控溅射技术在350℃的K9玻璃衬底上制备出了具有较好（100）择优取向的LaNiO3薄膜。通过对不同厚度薄膜的光学、电学以及薄膜结构等物理特性的测试分析，发现薄膜厚度小于100nm时为非晶结构，厚度大于150nm后出现了具有（100）择优取向的LaNiO3相。非晶结构的LaNiO3具有较高的面电阻和高的光学透射率，而晶化的LaNiO3薄膜具有类似于金属的导电能力和光学特性。薄膜的生长动力学和导电分析结果认为薄膜生长的初期会形成一个非晶过渡层。     

光学薄膜及其发展现状

介绍了传统光学薄膜的原理,并对反光膜、增透膜、纳米光学薄膜等传统光学薄膜的研究现状及应用情况,以及几种新型光学薄膜如高强度激光器、金刚石及类金刚石膜、软X射线多层膜、光电通信用光学薄膜的研究现状及应用进行了详细分析;最后对光学薄膜的发展前景进行了展望。     

用于微测辐射热计的氧化钒薄膜的光电性能研究

采用磁控溅射方法在p-Si(100)衬底上制备了VO2和择优取向的V6O13混合相成分的薄膜.利用X射线衍射(XRD)分析、原子力显微镜(AFM)、傅立叶红外光谱(FT-IR)分析及四探针测试方法,研究了薄膜的相成分和红外吸收特性,并测试分析了薄膜的电学热稳定性.研究结果表明,通过这种方法制备的氧化钒薄膜具有较低的电阻率和较高的电阻温度系数(TCR),并且具有良好的热稳定性,可以作为微测辐射热计的热敏材料.