Al Thin Layers Research Articles

Effect of incorporating aluminum wire mesh on the notched and un-notched strengths of glass fiber/epoxy composites

The fiber/metal composite technology consolidates the usefulness of metallic materials and fiber reinforced matrix systems. Glass laminate aluminum reinforced epoxy is a hybrid composite containing alternative thin layer of Aluminum (Al) plies and fiber reinforced epoxy. However, the low adhesion between Al thin layer and epoxy limits their application. In this work, we used Al wire meshes to toughen the neat E-glass fiber/epoxy composite. Un-notched and notched tensile and flexural tests were conducted to study the effect of incorporating Al wire meshes at different locations within the specimen thickness instead of the glass fiber plies on the mechanical properties of the produced materials. The results indicated that, incorporating Al mesh as a replacement of glass fibers could tailor the laminates strength, ductility and toughness. As the number of Al mesh layers increased, the specific tensile and flexural strengths decreased. The through-the-thickness position and orientation of Al mesh layer significantly affected the properties of the produced hybrid laminates. The presence of Al mesh at the outer layers highly reduced the tensile and flexural strengths. However, it improved the tensile and flexural strains and reaching an improvement of 54% and 117%, respectively. The energy absorption ability under tensile and flexural tests was highly improved with the addition of Al mesh layers reaching a maximum improvement of 210% and 166%, respectively. The mode I fracture toughness characterized by notched bending test was improved by 25.7% for samples with Al mesh layer replacing the third and sixth glass fiber layers.

Reflective Phosphor-in-Glass Color Converter for Laser-Driven White Lighting

In this work, we fabricated a phosphor-in-glass (PiG) film on Al-coated sapphire as reflective color converter driven by a laser diode. The borosilicate glass PiG film was sintered on heat-conducting sapphire and an Al thin layer with high reflectivity was deposited on the other surface of the sapphire, providing the function of heat dissipation and light reflection. The optical performance of the laser-driven white emitter (LD-WE) was adjusted by controlling the PiG film thickness. At a thickness of $120~\mu \text{m}$ , the LD-WE emits white light with a correlated color temperature (CCT) of 6733 K and a chromaticity coordinate of (0.3104, 0.3184). When the laser power increases from 0.32 to 1.12 W, the luminous flux increases from 19.3 to 129 lm and the light quality is stable. The color rendering index (CRI) of LD-WE reaches 82.5 by adding red phosphor. Furthermore, the converter has low working temperature from 30.7 to 45.6°C due to the effective heat transfer of sapphire.

Structure and Electrical Properties of ZnO Nanoparticles Blend with POT-DBSA

In this study, we report on a successful preparation nanocomposites poly (o-toluidine) (POT) doping with dodecylbenzene sulfonate acid (DBSA)/ ZnO by in-situ polymerization of (o-toluidine) monomer using ZnO nanoparticles (the weight ratios OT/ZnO: 1/5%, 1/10%, 1/15%). The composite films have been prepared by using the casting method on different substrate depending on the type of measurement. The surface morphology properties of the prepared samples were studied by the field emission scanning electron microscopy (FESEM). The results of FESEM indicate that ZnO nanoparticles were successfully embedded in the POT via chemical interactions between ZnO and (O-toluidine) monomer and the EDX spectrum showed the presence of element Zn in POT-DBSA/ZnO composites. The crystal structure was measured by x-ray directional and its pattern revealed the presence of ZnO in dopant polymer, in the diffraction patterns of POT-DBSA. The intensity of the peaks was increased as the amount of ZnO nanoparticles increased in POT-DBSA. The typical rectifying behaviour indicated that the formation of a diode observes by the I–V characterization of POT-DBSA/ZnO composites at thin film layer with top Al thin layer contact.

Measurement of proton microbeam profiles in atmosphere produced by single tapered glass capillary optics with an end window

SynopsisProfiles of 2.8 MeV H+ microbeam extracted from a single tapered glass capillary optics were meas-ured by two methods for a future irradiation to an outer organ of insect target. The halo component was analyzed to be 575 μm in full width at half maximum (FWHM) at a plastic tracking detector CR-39 located 1 mm down-stream of the capillary. The core component was examined by knife-edge method according to the ion energies. The profiles consisting of more energy-loss events have wider FWHM, which can be reduced by Al thin layers.

Structural studies of Al thin layer on misoriented GaAs(100) substrate by transmission electron microscopy

AbstractA thin Al layer has been grown on a misoriented GaAs(100) substrate by molecular beam epitaxy and its structure has been studied by means of transmission electron microscopy. The metal layer is formed as grains of three orientations Al(100), Al(110) and Al(110)R. Digital analysis of dark‐field micrographs made it possible to obtain their grain sizes and relative coverage areas. By comparison with an Al layer grown on an exactly oriented GaAs(100) substrate it has been found that on the vicinal surface the relative coverage area and grain size of the Al(110)R orientation increase and the Al(100) relative coverage area decreases. This is attributed to surface atomic steps, which have been visualized in high‐resolution micrographs. The edge misfit dislocation system at the Al/GaAs interface has been revealed, which is insensitive to the substrate misorientation. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

TEM interfacial characterization of CVD diamond film grown on Al inter-layered steel substrate

Al interlayer is precoated on pure iron or steel substrates for diamond film deposition. Microstructures and compositions around the interfacial region of diamond film/Al interlayer/substrates have been comprehensively analyzed by transmission electron microscopy (TEM). Using only a simple Al thin layer is not sufficient, as the integrity of the Al interlayer is easily destroyed during scratching pretreatment. Consequently, the continuity of diamond film is damaged and local carburization corrosion occurs on the substrate. The carburization products primarily consist of voluminous graphite and a large number of fine particles of iron carbide are dispersed at the interfacial region, inducing deteriorated interfacial adhesion. To solve it, an interdiffusion pretreatment of Al interlayer under annealing vacuum is required. The results show that a Fe–Al alloy facilitated the formation of a protective Al oxide layer and improved the diamond film deposition. However, the surface aluminizing process needs to be further optimized, as indicated by a comparison with the diamond deposition directly on Fe–Cr–Al bulk alloy substrate.

Triple-wavelength, narrowband Mg/SiC multilayers with corrosion barriers and high peak reflectance in the 25-80 nm wavelength region

We have developed new, Mg/SiC multilayer coatings with corrosion barriers which can be used to efficiently and simultaneously reflect extreme ultraviolet (EUV) radiation in single or multiple narrow bands centered at wavelengths in the spectral region from 25 to 80 nm. Corrosion mitigation was attempted through the use of Al-Mg or Al thin layers. Three different multilayer design concepts were developed and deposited by magnetron sputtering and the reflectance was measured at near-normal incidence in a broad spectral range. Standard Mg/SiC multilayers were also deposited and measured for comparison. They were shown to efficiently reflect radiation at a wavelength of 76.9 nm with a peak reflectance of 40.6% at near-normal incidence, the highest experimental reflectance reported at this wavelength for a narrowband coating. The demonstration of multilayer coatings with corrosion resistance and multiple-wavelength EUV performance is of great interest in the development of mirrors for space-borne solar physics telescopes and other applications requiring long-lasting coatings with narrowband response in multiple emission lines across the EUV range.

STRUCTURE AND PHOTOLUMINESCENT PROPERTIES OF SiCO THIN-FILMS DOPED WITH Al PREPARED BY DUAL MAGNETRON SPUTTERING

SiCO thin-films doped with aluminum (Al) prepared by alternate deposition of SiC and Al thin layers using Ar and O 2 as sputtering gas were deposited on n- Si substrates. The as-deposited thin-films were annealed under 600°C in nitrogen ambient. The thin-films have been characterized by atomic force microscopy, energy dispersive spectrometer, X-ray diffraction, fourier transform infrared spectroscopy, and photoluminescence spectra. The results showed that the introduction of Al promotes the formation of Si — C bonds, but hinders amorphous SiC to further transform to crystalline SiC . The doped Al would react with SiO x in the thin-films to form more Si particles which strongly affect the optical properties. After Al doped, there presented a seven times of enhancement emission band centered around 412 nm, which is ascribed to nanostructure Si -related defect centers embedded in the SiCO thin-films. The obtained results are expected to have important applications in modern optoelectronic devices.

Effect of annealing on structural and electrical properties of ZnO and In2S3:Al thin layers

Thin films of ZnO and In2S3:Al are deposited on Pyrex substrates by spray technique.Structural and electrical properties of ZnO and β-In2S3:Al compounds were studied using X Ray Diffraction (XRD), (MEB) and the Vander Pauw method before and after annealing.The X-rays revealed that, ZnO and In2S3:Al were well crystallized respectively in the hexagonal and cubic structure.The main orientations of ZnO were (101), (100) and (110). The (101) direction is the preferentially one. The annealing favors the preferential peak crystallization with a reduction of the grains size and the thickness layer.The β-In2S3 contain Aluminum inclusion by introducing the ratio x= [Al3+]/[In3+] in sprayed solution.X-ray diffraction spectra of In2−xAlxS3 thin layer, realized for the value of z equal to 20%, show well-defined peaks of (311), (400), (511), and (440) principal orientations corresponding to cubic structure of β-In2S3. For In2S3:Al, we note that the annealing increase the intensity of all peaks with an increase of the grains size and the thickness layer. Besides, thanks to the determination of the resistance from which we calculated resistivity, we note that the annealing increase conductivity of β-In2S3:Al and decrease it for ZnO.

Selective growth of GaN nanocolumns by Al thin layer on substrate

AbstractFor the application of GaN nanocolumns, one of the most important issues is to control their shapes and positions. We demonstrated a selective RF‐MBE growth of GaN nanocolumns using patterned Al thin pre‐deposited layers on a substrate via their nitridation. As the nanocolumns were grown at the edge of the nitrided Al patterns, a possibility of controlling the shape and the position of nanocolumns was suggested. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Effects of interfaces on nano-friction of vertically aligned multi-walled carbon nanotube arrays

Sliding friction properties of vertically aligned multi-walled carbon nanotube (VAMWNT) arrays have been investigated in current study in a quantitative manner. The VAMWNT arrays have been fabricated on an anodic aluminum oxide template by chemical vapor deposition at 650 °C. Friction force was measured in air by a modified atomic force microscopy (AFM) cantilever-bead assembly with 15 μm diameter borosilicate sphere attached to the end of the regular AFM cantilever. Quantitative measurements were achieved by using a novel in situ calibration methods recently developed based on diamagnetic levitation [Q. Li, K.-S. Kim, A. Rydberg, Rev. Sci. Instrum. 77 (2006) 065105-1-13]. The effects of different interfaces were studied using both cantilever-bead assembly coated with and without Al thin layer coatings. A reverse stick–slip behavior was observed in the current system as compared to the normal stick–slip behavior found in the literature.

Direct growth of three-dimensional multicomponent micropatterns of vertically aligned single-walled carbon nanotubes interposed with their multi-walled counterparts on Al-activated iron substrates

Vertically aligned single-walled carbon nanotubes (VA-SWNTs) have been synthesized by an Al-activated plasma-enhanced chemical vapor deposition (PECVD) method. On this basis, we have developed a facile but effective method for direct growth of multicomponent micropatterns of VA-SWNTs interposed within the patterned areas surrounded by vertically aligned multi-walled carbon nanotubes (VA-MWNTs) onto an Al-activated iron substrate. The Al-activated iron substrate was prepared by region-selectively depositing an Al thin layer on either an Fe-coated substrate or a commercially available iron foil. This simple approach allows for an effective integration of various aligned carbon nanotubes with different electronic characteristics into multifunctional materials and devices.

Effect of doping level and spray time on zinc oxide thin films produced by spray pyrolysis for transparent electrodes applications

In this paper, we present the results of optical, electrical and structural properties of zinc oxide (ZnO) semiconductors thin layers with various aluminium (Al) doping level and deposited at different spray time using the spray pyrolysis technique in atmospheric pressure. The study of optical properties from reflection and transmission spectra shows a high transmission value a band gap energy of about 3.33 eV and the reflection index is equal to 2.34 in the transparency range. The thickness is approximately equal to 1 μm. X-ray diffraction shows that these layers prepared at a substrate temperature of 380 °C, are well crystallized and oriented preferentially in the (0 0 2) direction. We also outperformed that ZnO:Al thin layers for a spray solution of 3% at.% Al doping rate and sputtered under 3600 s spray time, have a low value of resistivity of about 3 × 10 −3 Ωcm. Hence this allows us to use those layers in photovoltaic and solar applications as transparent electrodes.

Preparation of Zr 1− x Al xO 2 by annealing of ZrO x/Al thin films in the air atmosphere

Preparation of Zr 1− x Al x O 2 by annealing of ZrO x /Al thin layers in the reactive medium is presented in this work. At first ZrO x thin films were deposited by reactive cathodic arc evaporation. Cathodic arc evaporation is the most versatile PVD coating technology. The process uses arc evaporation to create highly ionized plasma. It allows the “droplets” to escape into the coating under special condition in the chamber. After complete analysis of the process of arc deposition, ZrO x thin films with thickness of ∼600 nm were deposited on Al 2O 3 and quartz substrates. Using vaporization on ZrO x thin films 10% mol of Al was deposited and these ZrO x /Al thin films were annealed at 500–900 °C in the air medium. The Zr 0.9Al 0.1O 2 thin films with nanocrystallite and two phases, monoclinic and cubic, were produced using the above-mentioned technique. The structure and optical properties of films were investigated by XRD, ellipsometry, photospectometry, respectively.

Transparent semiconducting ZnO:Al thin films prepared by spray pyrolysis

Aluminum doped zinc oxide (ZnO:Al) films which can be used as transparent electrodes or heating layers have been deposited by the low cost spray pyrolysis technique. Undoped and Al-doped ZnO films deposited using various preparation conditions and on different substrates (soda lime glass, quartz glass and crystalline quartz, respectively) have been studied. The effect of substrate type, temperature, deposition time and doping concentration on ZnO:Al thin layers have been investigated by analysing the optical and structural properties of the films. A substrate temperature of 770 K allows the preparation of nanosized ZnO:Al crystals with preferred [002] orientation. Films with optical transmission T>85% and a adjustable resistivity ρ between 2 and 100 Ω cm have been obtained. The resistivity value of the films can be adjusted by tuning suitable processing parameters. The feasibility of the spray pyrolysis technique for the preparation of thin semiconducting ZnO:Al films on conventional soda lime glass substrates is demonstrated.

Depth profiles in SiON and AlON thin films produced by ion implantation

Sialon ceramics have several interesting mechanical properties that make them candidates for applications at high temperatures. The aim of this work is to define experimental procedures to obtain homogeneous SiAlON thin films. Thin layers (< 200 nm) of oxinitride were synthesized using nitrogen and oxygen implantation into Si or Al layers deposited on B 4C or glassy carbon substrates. For this purpose, the deposited Si and Al thin layers have been successively implanted with 50 keV 15N and 18O for doses ranging from 1 × 10 17 to 1 × 10 18 ions/cm 2. High depth resolution profiles and stoichiometry have been measured using Rutherford backscattering spectroscopy (RBS) and the resonant nuclear reactions 15N(p,αγ) at 429 keV and 18O(p,γ) at 1928 keV. The chemical bonds were investigated by XPS and LEEIXS.

Aluminum Reflow Behavior in Via-Hole Filling Investigated by Molecular Dynamics Simulation and Computer Graphics

We have performed molecular dynamics simulation to study the fine structure of Al thin layer and Al reflow behavior in a temperature range of 300 K-1400 K. We have shown that at 300 K the Al atoms on the insulator surface do not migrate toward the via-hole. With increasing the temperature, the mobility of all the Al atoms increased and the via-hole was completely filled with the Al atoms at 1400 K. This acceleration of Al reflow behavior due to the rise of the temperature is in qualitatively good agreement with the experimental result. Furthermore, we clarified the dynamic transformation process of an Al thin-layer on SiO2 surface to an Al plug filling in the via-hole on an atomic scale. Hence, the effectiveness and the applicability of the molecular dynamics method to investigate the Al reflow behavior related to the fabrication of an electronic device were strongly confirmed.