Advanced Materials Research Vols. 602-604

Abstract: In this paper, using classical molecular dynamics, the growth of the amorphous silicon thin film deposited on the single crystal silicon is simulated and studied by Stillinger-Weber potential. The radial distribution functions of particles are calculated and the Voronoi diagrams of the films are given. The regular and irregular structures in the film are analyzed and the part crystallization condition is discussed. It is found that the features of the film are related with the ratio of the substrate temperature and the temperature of the incident atoms. The density of the deposited silicon film is obtained. The value of the density is about 2.2515g/cm³ which is consistent with the experiment data.

Abstract: [Pb_0.95(La_0.6Bi_0.4)_0.05][Zr_0.53Ti_0.47]O₃ (PLBZT) ferroelectric thin films have been synthesized on ITO-coated glass by sol-gel processing. Effects of annealing temperature on structure and properties of PLBZT have been investigated. With the increase of annealing temperature from 500°C to 550°C, the remanent polarization Pr increase slightly to the maximum value of 25.4μC/cm² due to the improvement in crystallization of PLBZT films. However, when the annealing temperature is more than 550°C, the pyrochlore phase appear and degrade the Pr of PLBZT thin films. The lowest leakage current density of 1.8×10^-9 A/cm² can be observed in PLBZT thin films when the annealing temperature is 550°C.

Abstract: Fluorocarbon films were deposited using a Pulsed Plasma Thruster. By means of mass spectrum analysis, the compositions of the Pulsed Plasma Thruster plume were studied. The microstructure and chemical bonding nature of the films were investigated by X-ray photoelectron spectroscopy. The plume consists primarily of C, F, CF, CF₂, CF₃, amounts of thruster body materials are detected as well. Five chemical bonds, CF₃, CF₂, CF, C-CF_x, and elemental carbon bonds are observed on the surface of all the deposited films, the content of the various chemical bonds change with deposited angle, the F/C ratio reaches a minimum value of 0.7643 at 15 degree, and increases gradually with deposited angle increasing from 15 degree to 60 degree.

Abstract: In this article, the polystyrene (PS) microspheres monolayer film was manufactured on silicon substrate by spin-coating, and the effect of PS microspheres concentration on preparation of monolayer film was discussed in detail. With a view to the application of graphic substrate technology, the etching effect with different technological parameter (etching time and power) was researched, and a set of appropriate process parameter were obtained, which met the requirements of preparation of the extension graphics silicon substrate.

Abstract: The BiFeO3 thin film was prepared by sol-gel process on Pt/Si substrates. The dependences of structural, electrical properties on annealed temperature were studied. X-ray diffraction (XRD) analysis revealed that the pure phase of BiFeO3 thin film was obtained when annealed below 650°C for 60 minutes in air. The film annealed at lower temperature had denser surface morphology, and showed better electrical characteristic.

Abstract: Chitin nanofibers were prepared from prawn shell by a simple mechanical treatment after the removal of proteins and minerals. Since the exoskeleton of prawn is made up of a finer structure nano-fibrillation of prawn shell is easy, which allows chitin nanofibers to be prepared under neutral pH conditions. The obtained nanofibers were observed by FE-SEM and found to have a uniform width of approximately 20-40nm and high aspect ratio that more than 1000. Due to the size effect of the chitin nanofibers, the nanocomposite films had high transparency that the chitin nanofibers/epoxy resin nanocomposite transmitted 85.2% of light compared to the light transmittance of pure epoxy resin（91%）and the light transmittance of pure chitin nanofibers sheet (70.1%) at a visible wavelength of 600nm. In the study the coefficient of thermal expansion (CTE) from 20 to 160°C of the epoxy resin sheet was measured to be 170 ppm/K. By adding 40 wt% of chitin nanofibers, the CTE of the epoxy resin dropped to 22 ppm/K, approximately 1/8th of its original value. The novel material is a candidate for transparent substrates in the manufacturing optoelectronic devices such as flexible displays and solar cells.

Abstract: This study deals with the fabrication and characterization of polymer matrix thin films containing high content titanium dioxide (TiO₂). Poly(diallyldimethylammonium chloride) (PDADMAC) membrane incorporated with different percentages of TiO₂ nanoparticles were prepared by solvent casting. The morphologies of the films were characterised by scanning electron microscopy (SEM), and its thermal behavior were characterised by thermogravimetry(TG). The results indicated that dense TiO₂/polymer thin films can been fabricated conveniently by solvent casting from aqueous solutions of TiO₂/PDADMAC when the concentrations of TiO₂ were lower than 40 wt%, and the thermal stability of the TiO₂/PDADMAC composites were greatly improved by the addition of TiO₂ moieties.

Abstract: A commercially available PET thin film material with pure aluminum material deposited on its two surfaces is studied in this work to investigate the relationship between the mechanical behaviors and the structure of this “composite” material with the application of the concepts for the composite mechanics. This kind of structure has excellent anti-corrosion properties and can act as the good functional barrier material. Experimental researches are further carried out here to study the mechanical performance under various loading conditions as well as the influence of loading rates over the structure’s failure behavior, and over its mechanical properties like the yielding strength and the elastic modulus.

Abstract: TiO₂ nanoporous thin films were fabricated by the hydrothermal method using tetrabutyl titanate as the precursor and used to assemble dye-sensitized solar cells. The properties which include the short-circuit photocurrent(I_SC),open-circuit voltage(V_OC) and the fill factor(FF)of the solar cells were tested. The microstructure of titania films were modulated by changing the hydrothermal reaction temperature and the amount of PEG and the influence on the properties of the solar cells by titania films weas studied. The results indicate that there are better photoelectric properties for TiO₂ films at the hydrothermal temperature fo 230°C and the additive amount of PEG being 5% of the mass of TiO₂. I_SC,V_OC and FF was 12.42mA, 681mV, and 0.52 respectively, the photoelectric conversion efficiency(η)was 4.37%．

Abstract: Polyvinyl Alcohol (PVA) sustained-release film is prepared using partial alcoholysis PVA and total alcoholysis PVA to study mechanism of the sustained-release film. The permeable rate of the PVA sustained-release film is measured using distilled water. The influence factors to the sustained-release speed are discussed, the swelling ratio and dissolve weight loss rate of PVA sustained-release film are measured, and its stability is studied. It is shown in result that with the increasing of the ratio of partial alcoholysis PVA BM-I(1788), the sustained-release speed increases gradually; the thinner the film, the larger the sustained-release speed; the swelling ratio reaches its maximum value when PVA BM-I(1788) ratio is 30%; the film has good, it can maintain the sustained-release property in relatively long time.