Nickel-induced microwheel-like surface morphological evolution of ZnO thin films by spray pyrolysis

Nickel?Czinc oxide (Ni?CZnO) thin films were deposited onto glass and tin-doped indium oxide-coated glass substrates by using a pneumatic spray pyrolysis technique at 450?°C from aqueous solutions of zinc acetate and nickel acetate precursors. The effect of nickel doping on structural, morphological and optical properties of the ZnO thin films has been studied. The X-ray diffraction patterns confirmed the polycrystalline nature of the films having hexagonal crystal structure. Ni?CZnO films with appropriate nickel doping revealed the occurrence of novel wheel-like surface morphology. The absorption edge of the Ni?CZnO films showed a red shift, meaning that the optical band gap energy decreases as the nickel doping concentration increases. A growth model is developed and proposed for the novel wheel-like morphology. All the thin films exhibited room-temperature photoluminescence. Pure ZnO and Ni?CZnO thin films were tested for their photoelectrochemical performance in 0.5 M Na₂SO₄ electrolyte solution. The values of fill factor and open circuit voltage were improved for the Ni?CZnO thin films.     

Reactively sputtered Ni, Ni(N) and Ni3N films: Structural, electrical and magnetic properties

Nickel thin films were deposited on glass substrates at different N₂ gas contents using a dc triode sputtering deposition system. Triode configuration was used to deposit nanostructured thin films with preferred orientation at lower gas pressure and at lower substrate temperature compared to the dc diode sputtering system. A gradual evolution in the composition of the films from Ni, Ni(N), to Ni₃N was found by X-ray diffraction analysis. The preferred growth orientation of the nanostructured Ni films changed from (1 1 1) to (1 0 0) for 9% N₂ at 100 °C. Ni₃N films were formed at 23% N₂ with a particle size of about 65 nm, while for 0% and 9% of nitrogen, the particles sizes were 60 nm, and 37 nm, respectively, as obtained by atomic force microscopy. Magnetic force microscopy imaging showed that the local magnetic structure changed from disordered stripe domains of about 200 nm for Ni and Ni(N) to a structure without a magnetic contrast, indicating the paramagnetic state of this material, which confirmed the structural transformation from Ni to Ni₃N.     

Ni,Ti, and NiTi laser ablation in vacuum and in water to deposit thin films or to generate nanoparticles in solution

An ns Nd:YAG pulsed laser was used to deposit thin films in a vacuum and to generate nanoparticles in the water of Ni, Ti, and NiTi alloys. Laser ablation was measured in terms of removing mass per laser pulse. The laser-generated plasma in vacuum was characterized in terms of temperature and energy of emitted particles. The ablation in water produces nanoparticles with dimensions of the order of 25 nm and solutions with concentrations of the order of some mg/ml. The NiTi alloy stoichiometry is well reported in the deposited thin film and in the composition of the produced nanoparticles.     

Method for producing graphite and alumina thin films

A simple comprehensible method for producing graphite and alumina films has been suggested. The optical properties of a graphite suspension in toluene and a suspension of natural clay with a high content of alumina particles in water have been studied. It has been found that the optical density of the suspensions varies from layer to layer, and the lowest optical density has been observed in upper layers. Graphite and aluminum films have been prepared by taking samples from different depths. The microstructure of the films has been examined. It has turned out that alumina particles coalesce into regularly shaped objects in the form of snowflakes. In addition, alumina films obtained from samples taken from different depths of the suspension have different thicknesses. In thin and thick films, the particle size is 0.29 and 2.81 μm or more, respectively.     

Silanation and stability of 3-aminopropyl triethoxy silane on nanosized superparamagnetic particles: I. Direct silanation

The direct silanation of nanosized superparamagnetic particles (γ-Fe₂O₃) using 3-aminopropyl triethoxy silane is described. The silanized films are characterized using X-ray photoelectron spectroscopy, diffuse-reflectance Fourier transform infrared spectroscopy and electrokinetics. The silanation is conducted in both organic (toluene) and water solutions to examine the solvent effect on the molecular orientation and packing density of the silanized films. Depending on the solvent, about 74 to 83% of amine groups are found to be un-protonated and remain reactive on the particles. In acidic environment, the films silanized in toluene are more stable than that in water, but both are unstable in basic environment.     

Influences of thin Ni layer on the electrical and absorption properties of PZT thin film pyroelectric IR sensors

A solid precursor was used to prepare ferroelectric lead zirconate titanate (PZT) 30/70 thin films using the sol–gel deposition method. To apply PZT thin films for uncooled pyroelectric IR sensors, a Ni layer was deposited onto the PZT thin films, serving both as a selective absorption layer and as the top electrode. The absorption properties of such Ni coated multi-layered pyroelectric sensors were studied in the visible and infrared wavelength ranges. The maximum absorption coefficient of this type of IR sensor was measured to be 0.8 at 0.633 μm and 0.7 at 4 μm wavelength, respectively. A striking asymmetric polarization hysteresis loop in these PZT thin films with Ni as the top electrode was observed as a direct consequence. This asymmetric polarization was attributed to cause the difference in the dynamic pyroelectric responses in these Ni/PZT/Pt films, poled either positively or negatively before the measurement.     

Nickel nanostructured materials from liquid phase photodeposition

Liquid Phase Photo-Deposition (LPPD) technique has been used to obtain both colloidal particles and thin films of metallic and chloride nickel from solutions of only precursor Ni(acac)₂ (acac=2,4-pentandionato). Metallic nickel was obtained from ethanol solutions by direct nickel(II) photoreduction at 254 nm and by acetone sensitised reaction at 300 nm. In this latter process the rate was higher than in the first one. NiCl₂ was formed from CCl₄ solution by a solvent-initiated reaction. TEM analysis, performed on colloidal particles of nickel, showed that their dimensions are in the range 2–4 nm. The films did not present carbon contamination and were characterized by AFM, XPS and GIXRD. Metallic films consisted of particles of 20–40 nm that are the result of the aggregation of smaller crystallites (4–5 nm). Larger agglomerations (around 200 nm) have been observed for NiCl₂ films.     

Particle size effect on thermal conductivity of AlN films with embedded diamond particles

Fabricating composite thin films is an effective and economic solution to improve the thermal performance of the films. The diamond particles of different sizes were successfully embedded in AlN thin films by a chemical solution approach, which was confirmed by scanning electron microscope, x-ray diffraction analysis and x-ray photoelectron spectroscopy. The thermal properties of the films embedded with different diamond particles were studied by using a 3-omega method, which was observed to be strongly dependent on the particle size. A 19 % enhancement in thermal conductivity can be achieved by embedding diamond particles of 1-μm radius in AlN thin films. However, the thermal conductivity decreases after embedding with 10-nm radius diamond particles. The results are discussed with high volume model, which confirms that the interface thermal resistance between the embedded materials and the films plays an important role in determining the thermal conductivity of the as-grown carbon material embedded AlN films.     

Adsorption properties of Mg–Al layered double hydroxides thin films grown by laser based techniques

Powdered layered double hydroxides (LDHs) have been widely studied due to their applications as catalysts, anionic exchangers or host materials for inorganic and/or organic molecules. Assembling nano-sized LDHs onto flat solid substrates forming thin films is an expanding area of research due to the prospects of novel applications as sensors, corrosion-resistant coatings, components in optical and magnetic devices.Continuous and adherent thin films were grown by laser techniques (pulsed laser deposition – PLD and matrix assisted pulsed laser evaporation – MAPLE) starting from targets of Mg–Al LDHs. The capacity of the grown thin films to retain a metal (Ni) from contaminated water has been also explored. The thin films were immersed in an Ni(NO₃)₂ aqueous solutions with Ni concentrations of 10^?3% (w/w) (1 g/L) and 10^?4% (w/w) (0.1 g/L), respectively. X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX) were the techniques used to characterize the prepared materials.     

The influence of pH electrolyte on the electrochemical deposition and properties of nickel thin films

Ni thin films were electrodeposited on gold substrate from chloride solution with different pH at room temperature. The effect of electrolyte pH on Ni coatings was studied by using the cyclic voltammetry, the scanning electron microscopy (SEM), x-ray diffraction, and alternating gradient force magnetometer measurements. From electrochemical measurements, the onset potential for reduction of Ni was gradually shifted towards more cathodic scan with increase in pH; this is due to the protons in the case of low pH values and to the hydroxide ions in the case of higher pH values. The SEM study showed that a granular and compact structure of the electrodeposited Ni layers and the variation of film morphology with bath pH are established. The x-ray diffraction spectra revealed the formation of fcc structure Ni thin films with a preferential orientation along the Ni(111). The size of the deposited crystals in both the cases has been found to be in the range of 49–153 nm. Magnetic properties such as coercivity and saturation magnetization showed strong dependence on the electrolyte solution pH and consequently the crystallite size. Coercivity higher than 130–160 Oe was achieved for a pH value of 4 to 5. The differences observed in the magnetic properties were attributed to the structural changes caused by the electrolyte pH.     

衬底材料对制备立方氮化硼薄膜的影响

较系统地研究了不同衬底材料对制备氮化硼薄膜的影响。用热丝增强射频等离子体CVD法,以NH3,B2H6和H2为反应气体,在Si,Ni,Co和不锈钢等衬底材料上,成功生长出高质量的立方氮化硼薄膜,还用13.56MHz的射频溅射系统将c-BN薄膜沉积在Si衬底上,靶材为h-BN(纯度为99.99％）,溅射气体为氩气和氮气的混合气体,所得到的氮化硼薄膜中立方相含量高于90%,用X射线衍射谱和傅里叶变换红谱对样品进行了分析表明,衬底材料与c-BN的晶格匹配情况,对于CVD生长立方氮化硼薄膜影响很大,而对溅射生长立方氮化硼薄膜影响不大。     

Study on metal microparticle content of the material transferred with Absorbing Film Assisted Laser Induced Forward Transfer when using silver absorbing layer

Absorbing Film Assisted Laser Induced Forward Transfer (AFA-LIFT) is a modified LIFT method where a high absorption coefficient thin film coating of a transparent substrate is used to transform the laser energy into kinetic in order to transfer the “target” material spread on it. This method can be used for the transfer of biomaterials and living cells, which could be damaged by direct irradiation of the laser beam. In previous experiments, ∼50-100 nm thick metal films have been used as absorbing layer. The transferred material can also contain metal microparticles originating from the absorbing thin film and acting as non-desired impurities in some cases. The aim of our work was to study how the properties (number, size and covered area) of metal particles transferred during the AFA-LIFT process depend on film thickness and the applied fluence. Silver thin films with different thickness (50-400 nm) were used as absorbing layers and real experimental conditions were modeled by a 100 μm thick water layer. The particles transferred without the use of water layer were also studied. The threshold laser fluence for the complete removal of the absorber from the irradiated area was found to strongly increase with increasing film thickness. The deposited micrometer and submicrometer particles were observed with optical microscope and atomic force microscope. Their size ranged from 100 nm to 20 μm and depended on the laser fluence. The increase in fluence resulted in an increasing number of particles of smaller average size.     

Investigation of the crystallinity,structural, and optical properties in hydrotreating of Li–W co-doped ZnO thin films

The hydrotreated Li–W co-doped ZnO (LWZO:H) thin films was prepared on quartz glass substrates by RF magnetron sputtering at substrate temperature 100 °C with varied hydrogen flow ratios. The X-ray diffraction spectra indicated that the hydrotreating Li–W co-doped ZnO films showed a preferred orientation toward the c-axis. The chemical compositions of all samples were confirmed by X-ray photoelectron spectroscopy, which clearly showed the existence of W as a doping element into ZnO crystal lattice. The surface morphology of LWZO:H thin films changed with the increasing R value can clearly be seen. The average transmittance of the films was found to be almost 85 % for the wavelength range of 400–1,200 nm. Meanwhile, the optical band gap increase of the films may be attributed to the band Burstein–Moss effect.     

Investigation of Physical and electrochemical properties of Ni doped CeO2 Thin films: DFT calculation

Undoped and Ni-doped thin films of cerium dioxide have been deposited by spray pyrolysis technique on the glass substrate at the optimized temperature (450 ± 5) °C. Thin films Ce_1-xNi_xO₂ doped by different concentrations of Ni was characterized by X-ray diffraction. Raman analysis showed a peak at 461 ± 1 cm⁻¹ position for the undoped film, which corresponds to the active mode (F_2g mode) of the cubic fluorite structure. SEM images showed that the particles have a uniform spherical shape. EDS data have confirmed all elements (Ce, Ni and O) existence. Optical properties of samples show a decrease in band gap energy with increasing the nickel rate. Cyclic voltammetry indicates that the storage capacity of samples increases as the Ni rate increases. The EIS of CeO₂/ITO electrodes displays a small semicircular at high frequency. The theoretical results obtained using WIEN2k match well with the experimental ones.     

Fabrication and structural characterization of metal films coated on cenosphere particles by magnetron sputtering deposition

Metal films were successfully coated on cenosphere particles using a magnetron sputtering deposition system in which a newly designed sample stage equipped with an ultrasonic vibration generator was used for the tumbling of cenosphere particles. It was found by FE-SEM and AFM results that the films were well compacted and highly uniform in thickness. Due to the difference in sputtering rate, the film thicknesses estimated from FE-SEM characterizations in backscattered mode were <10, 39, 50 and 134 nm for Co, Ni, Cu and Ag films, respectively, under the same sputtering deposition conditions. The RMS values derived from the AFM measurements were 1.94, 4.31, 10.92 and 18.33 nm for Co, Ni, Cu and Ag films, respectively, which can ascribe to the different crystallization behaviors for the four metals. The experiment results indicate that the coating method can be applicable for the fabrication of many other films on cenosphere particles which can be sputter deposited.     

Structural and magnetic properties of single-step electrochemically deposited nanocrystalline cobalt ferrite thin films

In this paper, we study the structural, surface morphological and magnetic properties of single-step electrochemically deposited cobalt ferrite thin films. The prepared films were nanocrystalline with cubic crystal structure. Scanning electron micrograph image showed that the cobalt ferrite thin film was uniformly distributed over the substrate in addition to some random overgrowth of porous particles. The saturation magnetization of 298 emu/c was confirmed when films were used in magnetic studies.     

Effect of nickel incorporation on the optical properties of diamond-like carbon (DLC) matrix

The present study investigates the optical behavior of composite nanostructured DLC based films and functional coatings. Diamond-like carbon (DLC) thin films were synthesized by electrodeposition method onto SnO₂-coated glass substrates using an electrolyte of a mixture of acetic acid and water. Nanoparticles of nickel were then introduced into the DLC matrix. Morphology of the metal incorporated thin films and distribution of nanoparticles were studied by SEM; continuous homogeneous distribution of the particles was observed. Raman spectroscopy showed additional peaks in addition to the peaks due to DLC matrix. FTIR spectra revealed new peaks in the lower wave number region due to metal inclusion. UV-vis transmittance studies were performed to calculate the band gap of the samples. The estimated band gap from the Tauc relation was found to vary from 2.63 eV for the virgin DLC to 1.48 eV for the metal incorporated DLC.     

对超声波作用下的化学浴沉积方法制备CdS薄膜的谱学分析

用化学浴沉积法制备了CdS薄膜 ,并研究了加超声波对CdS薄膜生长过程的影响。利用卢瑟福背散射 ,X 射线粉末衍射和扫描电子显微镜对薄膜的厚度、晶相和表面形貌进行了表征。结果表明施加超声波的作用能有效地改善薄膜的质量 ,制备出均匀、致密的有较好的晶体结构CdS薄膜。同时 ,通过时间的控制可以精确地控制薄膜在 5 0nm左右 ,以满足制备太阳能电池的特殊要求。     

Stable highly hydrophobic and oleophilic meshes for oil-water separation

This paper describes a simple method for fabricating both highly hydrophobic and oleophilic meshes by coating thin fluoro-containing films. The static contact angle of such meshes is greater than 150° for water, and close to 0° for kerosene, xylene and toluene. These meshes can separate water from oil effectively without resorting to any extra power or chemical agent. Moreover, they exhibited stable water resisting, anti-chemical erosion and anti-hot aging properties. It promises as a candidate for the separation of oil and water.