Film morphology and orientation of amino silicone adsorbed onto cellulose substrate

A series of amino silicones with different amino values were synthesized and adsorbed onto surfaces of cotton fibers and cellulose substrates. The film morphology, hydrophobic properties and surface composition of the silicones are investigated and characterized by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), contact angle measurement, X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance infrared (ATR-IR). The results of the experiments indicate that the amino silicone can form a hydrophobic film on both cotton fibers and cellulose substrates and reduce the surface roughness significantly. Furthermore, the roughness becomes smaller with an increase in the amino value. All these results suggest that the orientation of amino silicone molecule is with the amino functional groups of amino silicone molecule adsorbed onto the cellulose interface while the main polymer chains and the hydrophobic Si-CH₃ groups extend toward the air.     

衬底对Cu(In,Ga)Se2薄膜织构的影响

分别在苏打石灰玻璃、Mo箔、无择优取向的Mo薄膜以及(110)择优取向的Mo薄膜四种不同衬底上，采用共蒸发工艺沉积约2 μm厚的Cu(In,Ga)Se₂薄膜，用X射线衍射仪测量薄膜的织构，研究衬底对Cu(In,Ga)Se₂薄膜织构的影响.在以上四种衬底上沉积的Cu(In,Ga)Se₂薄膜的(112)衍射峰强度依次逐渐减弱，(220/204)衍射峰从无到有且强度逐渐增强.在苏打石灰玻璃和Mo箔衬底上的Cu(In,Ga)Se_{2关键词： 择优取向 Cu(In 2}薄膜')" href="#">Ga)Se₂薄膜 太阳电池     

Some aspects of interactions between HTSC-films and substrates

Different aspects of the interaction between YBa₂Cu₂O_y(YBCO) films and (100) ZrO₂〈Y〉 (YSZ) substrates have been investigated. It was determined using X-ray diffraction methods that the structural mismatch between the film and the substrate leads to a film deformation throughout its thickness. At the same time a strained layer appears in the substrate, whose thickness is proportional to the film thickness. The surface morphology changes of YBCO films which take place with variation of the growth temperaturet_sin the vicinity of the optimum temperature lead to changes of the film grain structure probably connected with nucleation centers. Tl₂Ba₂CaCu₂O_y(TBCCO) films on YSZ substrates were also synthesized. It was found that the dependence of the TBCCO film surface morphology changes with annealing temperature and the dependence of YBCO film surface morphology changes ont_sare similar.     

Studies of electrochemically grafted thin organic layers on inorganic surfaces with infrared spectroscopic ellipsometry

We present IR spectroscopic ellipsometry (IRSE) measurements of electrochemically grafted organic ultrathin films down to monolayer thickness. The formation of organic layers of 4-methoxybenzene (anisole) on TiO₂, Au, and Si(111) surfaces was confirmed from observation of the respective absorption bands in the ellipsometric spectra. We discuss the orientation of molecules in a thin film on an Au substrate and in a thick film grafted on a TiO₂ substrate. The appearance of silicon oxide related bands in the IRSE spectra shows that oxidation is a side reaction of the electrochemical grafting on Si substrates. These results demonstrate the potential of IRSE application in studies of interfacial structures and thin film engineering. PACS 68.35.Ja; 82.45.Wx; 82.45.Jn     

Synthesis,structure, and electrochemical properties of epitaxial perovskite La0.8Sr0.2CoO3 film on YSZ substrate

Epitaxial films of the perovskite, La_0.8Sr_0.2CoO₃ (LSC), for SOFCs cathode were deposited on yttria-stabilized zirconia (YSZ) single crystals by pulsed laser deposition method. The films were characterized by thin-film X-ray diffraction measurement, atomic force microscopy (AFM), transmission electron microscope (TEM), and ac impedance spectroscopy. The film orientations depend on the substrate planes. The LSC films on the YSZ (100) and (111) substrates showed the (110) orientation with different twin structures, while those on the YSZ (110) had (100) and (112) orientations. Surface morphology of the films also depends on the substrate orientations. These films showed different electrode properties depending on the orientations. The relationships between the properties, the film orientations, surface morphology, and lattice misfit are discussed.     

Synthesis of ZnAl<Subscript>2</Subscript>O<Subscript>4</Subscript>/α-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> complex substrates and growth of GaN films

With the solid phase reaction between pulsed-laser-deposited (PLD) ZnO film and α-Al₂O₃ substrate, ZnAl₂O₄/α-Al₂O₃ complex substrates were synthesized. X-ray diffraction (XRD) spectra show that as the reaction proceeds, ZnAl₂O₄ changes from the initial (111)-oriented single crystal to poly-crystal, and then to inadequate (111) orientation. Corresponding scanning electron microscope (SEM) images indicate that the surface morphology of ZnAl₂O₄ transforms from uniform islands to stick structures, and then to bulgy-line structures. In addition, XRD spectra present that ZnAl₂O₄ prepared at low temperature is unstable at the environment of higher temperature. On the as-obtained ZnAl₂O₄/α-Al₂O₃ substrates, GaN films were grown without any nitride buffer using light-radiation heating low-pressure MOCVD (LRH-LP-MOCVD). XRD spectra indicate that GaN film on this kind of complex substrate changes fromc-axis single crystal to poly-crystal as ZnAl₂O₄ layer is thickened. For the single crystal GaN, its full width at half maximum (FWHM) of X-ray rocking curve is 0.4°. Results indicate that islands on thin ZnAl₂O₄ layer can promote nucleation at initial stage of GaN growth, which leads to the (0001)-oriented GaN film.     

Laser deposition of iron on graphite substrates

Pulsed laser deposition of iron atoms on graphite substrates was performed to produce iron carbide films. Mössbauer spectra of the sample revealed that iron carbide was produced on the substrate surface and that an α-Fe layer was produced above the iron carbide layer. When the substrate temperature was maintained at 300 K, the iron carbide layer had a hyperfine magnetic distribution because it contained high density of defects. Laser deposition of Fe at 570 K produced cementite Fe₃C with fewer defects due to enhancement of thermal reactions or annealing of the films. The orientation of hyperfine field of the Fe₃C film was parallel to the substrate surface.     

蓝宝石基片上制备大面积Tl2Ba2CaCu2O8超导薄膜

在2英寸双面蓝宝石基片上采用CeO₂作为缓冲层制备了高质量Tl₂Ba₂CaCu₂O₈(Tl-2212)超导薄膜.以金属铈作为溅射靶材,采用射频磁控反应溅射法生长了c轴织构的CeO₂缓冲薄膜,并研究了不同生长条件对于CeO₂缓冲层的晶体结构及表面形貌的影响.超导薄膜采用直流磁控溅射和后热处理的方法制备.扫描电子显微镜(SEM)图像显示,超     

Electrochemical behaviors of the magnesium alloy substrates in various pretreatment solutions

Interface reactions and film features of AZ91D magnesium alloy in pickling, activation and zinc immersion solutions have been investigated. The surface morphologies of the specimens were observed with scanning electron microscope (SEM). Electrochemical behaviors of AZ91D magnesium alloy in the baths of pickling, activation and zinc immersion were analyzed based on the open circuit potential (OCP) - time curves in various solutions. The results show that the corrosive rate in HNO₃ + CrO₃ or HNO₃ + H₃PO₄ pickling solution was more rapid than in KMnO₄ pickling-activation solution. Both α phase and β phase of the substrates were uniformly corroded in HNO₃ + CrO₃ or HNO₃ + H₃PO₄ pickling solution, the coarse surface can augment the mechanical occlusive force between the subsequent coatings and the substrates, so coatings with good adhesion can be obtained. In HF activation solution, the chromic compound formed via HNO₃ + CrO₃ pickling was removed and a compact MgF₂ film was formed on the substrate surface. In K₄P₂O₇ activation solution, the corrosion products formed via HNO₃ + H₃PO₄ pickling were removed, a new thin film of oxides and hydroxides was formed on the substrate surface. In KMnO₄ pickling-activation solution, a film of manganic oxides and phosphates was adhered on the substrate surface. Zinc film was symmetrically produced via K₄P₂O₇ activation or KMnO₄ pickling-activation, so it was good interlayer for Ni or Cu electroplating. Asymmetrical zinc film was produced because the MgF₂ film obtained in the HF activation solution had strong adhesive attraction and it was not suitable for interlayer for electroplating. However, the substrate containing compact MgF₂ film without zinc immersion was fit for direct electroless Ni-P plating.     

The growth and domain structure of YBa2Cu3Ox films on neodymium gallate substrates with a deviation of the normal to the surface from the [110] direction in NdGaO3

The growth, crystal structure, and electrophysical properties of YBa₂Cu₃O_x (YBCO) epitaxial films grown with and without a CeO₂ epitaxial sublayer on NdGaO₃ (NGO) substrates with the normal to the surface deviating from the [110] axis by 5° to 26.6° around the [001] axis are investigated. It is shown that the orientation of YBCO epitaxial films grown on such substrates is determined by the existence of symmetry-equivalent directions in the substrate and in the CeO₂ layer, as well as by the rate of film deposition. For a high deposition rate, YBCO films grow on the CeO₂ sublayer in the [001] orientation irrespective of the orientation of the substrate and the sublayer. It was found that when the angle of deviation of the substrate plane is from the (110) NGO plane, twinning of one or both twinning complexes in YBCO may be suppressed.     

Synthesis and tailoring of GaN nanocrystals at room temperature by RF magnetron sputtering

We report here the synthesis of hexagonal GaN nanocrystals on p-silicon substrates by Radio-Frequency (RF) magnetron sputtering without substrate heating or by post-deposition annealing treatment. GaN nanocrystals are synthesized and tailored as a function of RF power at constant Ar and N₂ flow rates (working pressure). The observed reduction in grain sizes as a function of RF power has been correlated with an increase in compressive strain. The effect of RF power on crystallite orientation has been determined by diffraction intensities using the degree of c-axis orientation. Atomic force microscopy shows uniform lateral nanocrystal sizes with spherical in shape by insignificant difference in Root-Mean-Square (RMS) roughness values for all the deposited thin films. Transmission electron microscope and field emission-scanning electron microscope studies have been performed to understand the surface morphologies and grain sizes. Thus, tailoring the size of the nanocrystals has been discussed by correlating RF powers, working pressures and cathode voltages on lattice vibrations.     

Structural, optical and electrical properties of tin oxide thin film deposited by APCVD method

Tin oxide (SnO₂) thin films have been grown on glass substrates using atmospheric pressure chemical vapour deposition (APCVD) method. During the deposition, the substrate temperature was kept at 400°C–500°C. The structural properties, surface morphology and chemical composition of the deposited film were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and Rutherford back scattering (RBS) spectrum. XRD pattern showed that the preferred orientation was (110) having tetragonal structure. The optical properties of the films were studied by measuring the transmittance, absorbance and reflectance spectra between λ = 254 nm to 1400 nm and the optical constants were calculated. Typical SnO₂ film transmits ∼ 94% of visible light. The electrical properties of the films were studied using four-probe method and Hall-voltage measurement experiment. The films showed room temperature conductivity in the range 1.08 × 10² to 1.69 × 10² Ω⁻¹cm⁻¹.     

IR and SFM study of PTCDA thin films on different substrates

FT-IR spectroscopy and SFM were used to investigate the growth of thin films of the organic semiconductor 3,4,9,10-perylenetetracarboxylicdianhydride (PTCDA) deposited by vacuum sublimation onto various substrates, i.e. Ag(111) layers on mica, KBr(100), mica, oxidized Si, and TiO₂ nanoparticles on Si. Layer thicknesses of PTCDA varied from 10 to 1500 nm.The anhydride vibrations of PTCDA differ for the used substrates, which can be connected to the orientation of the molecules relative to the substrate surface and the film morphology as detected in the SFM pictures.     

Effect of surface preparation on the morphology of ZnO nanorods

The effects of Si substrate orientation and surface treatment on the morphology and density of Zinc oxide (ZnO) nanorods were investigated. The size and density of ZnO nanorods were influenced by Si substrate orientation and surface preparation. ZnO nanorods synthesized on the ideally H-terminated Si(1 1 1) prepared with an NH₄F solution resulted in the biggest size and the lowest density. It is suggested that the smoother surface of the Si substrate and lattice shape match with a larger atomic distance result in the increase of the ZnO seedlayer's grain size, which in turn enhances the size of ZnO nanorods grown on it. The optical properties of the ZnO nanorods were affected by their size and crystallinity. The smallest ZnO nanorods with a preferential c-axis orientation synthesized on the HF-treated Si(1 1 1) surface showed the highest intensity ratio of UV to visible emission, and the biggest ZnO nanorods synthesized on the N₂-sparged NH₄F-treated Si(1 1 1) surface showed the lowest intensity ratio of UV to visible emission. Therefore, it can be concluded that Si substrate orientation and surface preparation significantly affect the optical properties of ZnO nanorods.     

Epitaxially grown zinc oxide films for electro-optic and acousto-optic interactions

Measurements of acoustic surface waves (ASW) and optical guided waves (OGW) wave properties have been carried out on chemical vapor deposited (CVD) epitaxial zinc oxide (ZnO) films on sapphire (Al₂O₃) substrates of different orientations. Surface preparation and orientation effects have been studied. Untuned acoustic insertion loss of 40 dB at 160 MHz and optical propagation loss of better than 5 dB/cm at 6328Å for the TE₀ mode were obtained in a 2μm thick (11$\text{2}$4) ZnO film deposited on a (0001) sapphire substrate.     

蓝宝石基片的处理方法对ZnO薄膜生长行为的影响

采用反应射频磁控溅射方法,在经过不同方法处理的蓝宝石基片上,在同一条件下沉积了ZnO薄膜.利用原子力显微镜、X射线衍射、反射式高能电子衍射等分析技术,对基片和薄膜的结构、表面形貌进行了系统表征.研究结果显示,不同退火条件下的蓝宝石基片表面结构之间没有本质的差异,均为α-Al₂O₃ (001)晶面,但基片表面形貌的变化较大.在不同方法处理的蓝宝石基片上生长的ZnO薄膜均具有高c轴取向的织构特征,但薄膜的表面形貌差异较大.基片经真空退火处 关键词： ZnO薄膜 反应磁控溅射 基片处理 形貌分析     

Control of tensile stress on inducing formation and tunability of (100) oriented Pb x Sr1−x TiO3 thin films

(100) Oriented Pb _x Sr_1?x TiO₃ (PSTO) thin films are prepared on indium tin oxide (ITO)/glass substrates by sol–gel technique while inserting doped PbTiO₃ (PTO)-inducing layer in between. The effect of tensile stress in PSTO on tunability and (100) orientation of the thin films was investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscope, and atomic force microscope, respectively. Results show that PSTO thin film deposited on doped PTO has (100) oriented structure while it is randomly oriented when deposited directly on the ITO/glass substrate. Lattice mismatch between PSTO and PTO appears, in which the in-plane lattice constant c is 0.3922–0.3924 nm in the former and 4.02–4.07 nm in the latter, respectively, contributing tensile stress in the PSTO due to different lattice constants between them. The stress in the PSTO thin film is 3.04, 3.15, 3.59 and 4.47 GPa when the doped PTOs are Fe–PTO, Tb–PTO, Co–PTO and Zn–PTO, respectively. The orientation degrees of PSTO thin films are from 89.63, 90.31, 91.92 to 93.29 % with increasing stress of PSTO on Fe–PTO, Tb–PTO, Co–PTO and Zn–PTO, respectively. Tunabilities of the well-oriented PSTO thin films increase in ascending order of 63 < 65 < 69 < 73 % when induced by oriented PTO layers of Fe–PTO, Tb–PTO, Co–PTO and Zn–PTO, respectively, which is in accordance with the degree of (100) orientation appearing in the thin films. The high tunability appears in the PSTO thin film while high (100) orientation is derived from the tensile stress. It is much higher than that of randomly oriented PSTO thin film.     

Fabrication of textured SnO2:F thin films by spray pyrolysis

Transparent conductive SnO₂:F thin films with textured surfaces were fabricated on soda-lime-silica glass substrates by spray pyrolysis. Structure, morphology, optical and electrical properties of the films were investigated. Results show that the film structure, morphology, haze, transmittance and sheet resistance are dependent on the substrate temperature and film thickness. An optimal 810 nm-thick SnO₂:F film with textured surface deposited at 520 °C exhibits polycrystalline rutile tetragonal structure with a (2 0 0) orientation. The sheet resistance, average transmittance in visible region, and haze of this film were 8 Ω/□, 80.04% and 11.07%, respectively, which are suitable for the electrode used in the hydrogenated amorphous silicon solar cells.     

Characteristics of SrBi2Ta2O9 ferroelectric films in an in situ applied low electric field prepared by metalorganic decomposition

SrBi₂Ta₂O₉ (SBT) films were prepared on Pt/TiO₂/SiO₂/Si substrates at 750 °C in oxygen by metalorganic decomposition method. A low electric field was in situ applied during the film crystallization. It was first found that a low electric field and its direction have significant influence on the microstructures and ferroelectric properties of SBT films. Under a positive electric field (assuming that the bottom electrode is electrically grounded), the films show stronger c-axis-preferred orientation than without electric field and under a negative electric field. As a possible origin is proposed that the interface-induced nucleation growth between SBT and Pt coated substrate with application of low electric field plays a key role. Above all, an in situ applied low electric field during the film crystallization is a promising technique controlling film orientation for film preparation by wet chemical method.     

Nanocrystalline ZnO film deposited by ultrasonic spray on textured silicon substrate as an anti-reflection coating layer

A ZnO thin film was successfully synthesized on glass, flat surface and textured silicon substrates by chemical spray deposition. The textured silicon substrate was carried out using two solutions (NaOH/IPA and Na₂CO₃). Textured with Na₂CO₃ solution, the sample surface exhibits uniform pyramids with an average height of 5 μm. The properties and morphology of ZnO films were investigated. X-ray diffraction (XRD) spectra revealed a preferred orientation of the ZnO nanocrystalline film along the c-axis where the low value of the tensile strain 0.26% was obtained. SEM images show that all films display a granular, polycrystalline morphology. The morphology of the ZnO layers depends dramatically on the substrate used and follows the contours of the pyramids on the substrate surface. The average reflectance of the textured surface was found to be around 13% and it decreases dramatically to 2.57% after deposition of a ZnO antireflection coating. FT-IR peaks arising from the bonding between Zn–O are clearly represented using a silicon textured surface. A very intense photoluminescence (PL) emission peak is observed for ZnO/textured Si, revealing the good quality of the layer. The PL peak at 380.5 nm (UV emission) and the high-intensity PL peak at 427.5 nm are observed and a high luminescence occurs when using a textured Si substrate.