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Abstract: CdSe thin films have been grown on GaAs (001) substrates by molecular beam epitaxy (MBE). The effects of substrate temperature and annealing treatment on the structural properties of CdSe layers were investigated. The growth rate slightly decreases due to the accelerated desorption of Cd from CdSe surface with an increase in the temperature. The sample grown at 260°C shows a polycrystalline structure with rough surface. As the temperature increases over 300°C, crystalline CdSe (001) epilayers with zinc-blende structure are achieved and the structural quality is improved remarkably. The epilayer grown at 340°C displays the narrowest full-width at half-maximum (FWHM) from (004) reflection in double-crystal X-ray rocking curve (DCXRC) and the smallest root-mean-square (RMS) roughness of 0.816nm. Additionally, samples fabricated at 320°C were annealed in air for 30min to study the films’ thermal stability. X-ray diffraction (XRD) results indicate that the zinc-blende structure remains unchanged when the annealing temperature is elevated to 460°C, meaning a good thermal stability of the cubic CdSe epilayers. [Copyright &y& Elsevier]

Abstract: Polypropylene (PP) was modified with 2-hydroxyethyl acrylate (HEA) by solution radical grafting to introduce active hydroxyl groups on polypropylene backbone (PP-g-HEA). Then the biomimic monomer, 2-methacryloyloxyethyl phosphorycholine (MPC), was grafted onto the surface of PP-g-HEA film (PP-g-HEA-g-MPC) by redox graft polymerizations with ceric(IV) ammonium nitrate as an initiator. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed that the HEA and MPC were introduced onto PP molecular chains and the copolymer, PP-g-HEA-g-MPC were formed. The water contact angle measurements demonstrated that the final modified PP film exhibited a better hydrophilic surface compared to the neat PP film. The platelets adhesion on the neat PP, PP-g-HEA and PP-g-HEA-g-MPC film was examined by scanning electron microscopy (SEM). It was found that a large number of platelets were adhered and activated on the surface of neat PP and PP-g-HEA films, while the number of platelets on PP-g-HEA-g-MPC surface was decreased remarkably. The result revealed that the introduction of poly(MPC) onto the PP surface improved the hemocompatibility of PP substantially. [Copyright &y& Elsevier]

Abstract: Epitaxial ZnO thin films have been synthesized directly on Si(111) substrates by pulsed laser deposition (PLD) in vacuum. The reflection high-energy electron diffraction (RHEED) indicates that streaky patterns can be clearly observed from the ZnO epilayers prepared at 600 and 650°C, revealing a two-dimensional (2D) growth mode. While the ZnO thin film deposited in oxygen ambient shows ring RHEED pattern. There is a compressive in-plane stress existing in the ZnO epitaxial film, but a tensile one in the polycrystalline film. Compared with the ZnO epilayer, the ZnO polycrystalline film shows more intense ultraviolet emission (UVE) with a small full width at half maximum (FWHM) of 89meV. It is suggested that the atomically flat epilayers may be powerfully used as transitive stratums to grow high-quality ZnO films suitable for the fabrication of optoelectronic devices. [Copyright &y& Elsevier]

Abstract: ZnO thin films with highly c-axis orientation have been fabricated on p-type Si(111) substrates at 400°C by pulsed laser deposition (PLD) from a metallic Zn target with oxygen pressures between 0.1 and 0.7mbar. Experimental results indicate that the films deposited at 0.3 and 0.5mbar have better crystalline and optical quality and flatter surfaces than the films prepared at other pressures. The full width at half maximum (FWHM) of (0002) diffraction peak decreases remarkably from 0.46 to 0.19° with increasing annealing temperature for the film prepared at 0.3mbar. In photoluminescence (PL) spectra at room temperature, the annealed film at 700°C exhibits a smaller ultraviolet (UV) peak FWHM of 108meV than the as-grown film (119meV). However, an enhanced deep-level emission is observed. Possible origins to above results are discussed. [Copyright &y& Elsevier]

ZnO thin films were fabricated on Si (1 1 1) substrates by oxidation of metallic Zn films in air. A thin layer of Au was used to enhance the adhesion of the Zn atoms to the Si surface during depositing the Zn films on the substrates at room temperature (RT) by thermal evaporation. X-ray diffraction (XRD) studies indicate that the ZnO film prepared at 500 °C has better crystalline quality than films prepared at other temperatures. In photoluminescence (PL) spectra at room temperature, the film oxidized at 500 °C exhibits the biggest intensity ratio of 162 of ultraviolet (UV) emission to deep-level emission and the narrowest UV peak full width at half maximum (FWHM) of 94.8 meV. These results reveal that high-quality ZnO thin films with good crystallinity and strong UV emission can be achieved at such low temperature. It was also observed that the deep-level emission would become dominant in the PL spectra for the samples annealed at high temperatures above 700 °C, and the possible origin was discussed. [Copyright &y& Elsevier]

A mild and low-cost strategy for fabricating nanoporous silver (NPS) thin films loaded on Ni wire were reported via co-electrodeposition of Ag-Sn alloy and subsequent dealloying in alkaline solution. Scanning electron microscope (SEM) and energy dispersive spectrum (EDS) were performed to investigate the morphology and composition of the electrodes. The crystal structures of the precursor alloy and NPS were examined by X-ray diffraction (XRD). After selectively etching the Sn out of the Ag-Sn alloy, an unordered three-dimensional bicontinuous nanoporous structure was observed, with a pore size of ∼50–120 nm and a ligament size of ∼40–200 nm. The NPS electrodes presented linear current response to hydrogen peroxide under the concentration ranging from 0.010 to 8.000 mM, with an excellent correlation coefficient (R 2 ) of 0.99998. The high sensitivity, reliability, anti-interference ability, stability and short response time indicate its potential in real-time monitoring H 2 O 2 . [ABSTRACT FROM AUTHOR]

Abstract: We described a two-step process to fabricate the heparinized polypropylene (PP) film using cyanuric chloride (CC) as a trifunctional reagent and poly (ethylene glycol) methacrylate (PEGMA) as a spacer. The modified PP films were characterized by attenuated total reflectance FT-IR and X-ray photoelectron spectroscopy; the content of PEGMA and heparin were determined by gravimetric method and a toluidine blue assay, respectively. For the PP-g-PEGMA films, it was found that small size protein BSA tended to adsorb on the surface of low molecular weight monomer grafted PP, whereas big spindle-shaped fibrinogen tended to adsorb on the surface of high molecular weight monomer grafted PP. We gave a definition of anti-protein adsorptive factor r with two model proteins, albumin and fibrinogen. The results by platelet adhesion and plasma recalcification time (PRT) experiments indicated that the factor r could be used to quantitatively evaluate the anticoagulant tendency of PP-g-PEGMA modified films. For the PP-g-PEGMA-g-heparin modified films, the surface was proved to have a high bioactivity by the adsorption of AT III assay and very low platelet adhesion. It indicated that immobilization of heparin on the PP film with PEGMA as a spacer was an effective way to improve the hemocompatibility of PP. [Copyright &y& Elsevier]

Abstract: A stable organic solar cell with structure of ITO/buffer/donor/acceptor/cathode is presented. A thin layer (5nm) of MoO3-doped CuPc is adopted as the buffer in CuPc/C60 organic heterojunction photovoltaic (PV) solar cells, resulting in two times longer lifetime. The surface morphology of buffer layer plays a decisive role in improving the stability. [Copyright &y& Elsevier]