Powder Target Research Articles

Growth of ErAs Nanoparticles by Pulsed Laser Ablation in an Inert Environment

The incorporation of ErAs nanoparticles into III–V semiconductor films has been shown to dramatically alter the properties of the resulting nanocomposite, while maintaining an epitaxial relationship throughout the film. Even though these composites have been extensively studied, little work has been done on the particles themselves, absent of the host matrix. In this paper, we demonstrate ErAs nanoparticle growth outside of a host matrix by laser ablation in an inert environment. Rietveld refinement was used to determine the compositions of ablation targets and resulting powders to better understand the requirements for the growth of binary nanoparticles from pressed powder targets and the limiting factors for particle growth. Powders with an ErAs concentration of 67.1% were obtained, and higher concentrations are expected to be achieved with higher purity targets.

Characteristics of the Structure and Properties of ZnSnO3 Films by Varying the Magnetron Sputtering Parameters

Transparent conductive oxide ZnSnO3 films were prepared by radio-frequency magnetron sputtering from powder targets and were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, atomic force microscopy, surface profile, UV–Vis spectroscopy, and Hall effect. The structures of the films were either amorphous or nanocrystalline depending on sputtering parameters including deposition time, target power, chamber pressure, and the target–substrate separation. The average transmittance of the ZnSnO3 films within the visible wavelength was approximately 80% and the resistivity of the ZnSnO3 films was in the range of 10−3–10−4 Ω cm. The structural, optical, and electrical properties of the ZnSnO3 films could be adjusted and regulated by optimizing the sputtering process, allowing materials with specific properties to be designed.

Thin-film heterostructures based on oxides of copper and zinc obtained by RF magnetron sputtering in one vacuum cycle

Investigations of formation conditions of oxide heterostructures ZnO/CuO in the same vacuum cycle using RF magnetron sputtering of powder targets of zinc and copper oxides were carried out. The optical and electrical properties of the thin film structures were studied.

Highly selective H2S gas sensor based on Cu-doped ZnO nanocrystalline films deposited by RF magnetron sputtering of powder target

Cu – doped ZnO (CZO) films were synthesized by RF magnetron sputtering of composite target prepared with powders of ZnO and copper. Crystalline nature, morphology and chemical/electronic composition of the films were investigated by X-ray diffraction (XRD), Atomic Force Microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). XRD showed hexagonal wurtzite structure with strong c-axis orientation for both doped and undoped films. AFM study revealed uniform deposition of nanocrystallites and XPS confirmed the Cu incorporation into ZnO lattice. Further the H2S sensing properties of the CZO films were investigated at different operating temperatures and gas concentrations. While all the doped films were highly selective to H2S, 2% CZO film showed highest sensitivity at an operating temperature of 250 °C.

Electrical and Optical Properties of Hydrogen Doped Aluminum-Doped Zinc Oxide Thin Films for Low Cost Applications

Aluminum-doped zinc oxide (AZO) thin films were prepared on glass substrate using a magnetron sputtering system. In this work, a powder target was used as a source material for low cost applications, instead of a conventional sintered ceramic target. The effects of the hydrogen gas ratio on the electrical and optical properties of the AZO films. The hydrogen doped AZO (AZO:H) films had a hexagonal polycrystalline structure. A small amount of hydrogen gas deteriorated the electrical and optical properties of the AZO:H films. However, these properties improved, as the H2/(H2 + Ar) gas ratio increased. The AZO:H films grown at an H2/(H2+Ar) ratio of 10% showed good properties for low cost applications, such as a low resistivity of 1.35 x 10(-3) Ω-cm, high average transmittance of 83.1% in the visible range of light.

Target nanomaterials at CERN-ISOLDE: synthesis and release data

Five different nanostructured target materials were tested and operated at ISOLDE in the year of 2014, three of them being carbon-based nanocomposites. In most cases such target materials have higher radioisotope intensities than standard targets and with apparently longer release characteristics. Here, an isotope release profile from a standard calcium oxide (CaO) powder target is compared to the nanostructured one. For all target materials, the synthesis is the key process since it determines the material characteristics and maximum operation temperature which, in turn, defines the final isotope yields (especially for exotic isotopes). An unexpected release of Ar isotopes from a nanometric CaO powder target, with its oven set to room temperature is described and a release mechanism is proposed: spallation recoil momentum from the natCa(p,x)35Ar reaction.

Residual stress and bending strength of ZnO films deposited on polyimide sheet by RF sputtering system

Zinc oxide (ZnO) films were deposited on a soft polyimide sheet substrate by radio frequency sputtering with a ZnO powder target, and the films' crystal orientations and residual stress were investigated using x-ray diffraction as a function of substrate temperature. C-axis oriented ZnO films were achieved using this ZnO powder target method. The ZnO films exhibited high compressive residual stresses between −0.7 and −1.4 GPa. Finally, the authors examined the strength of the obtained film by applying tensile bending loads. No cracks were observed on the surfaces of the ZnO films after a bending test using cylinders with diameters >25 mm. After a bending test using a cylinder with a diameter of 19 mm, large cracks were formed on the films. Therefore, the authors concluded that the tensile bending strength of the obtained films was greater than ∼420 MPa.

Lithium titanium oxynitride thin film with enhanced lithium storage and rate capability

The lithium titanium oxynitride (LTON) thin film electrode was prepared by radio frequency (RF) magnetron sputtering deposition using a cubic spinel structure Li4Ti5O12 (LTO) powder target in a N2 atmosphere for lithium ion batteries. XRD and SEM test results showed that the thin film was composed of weak crystal or amorphous structure and that its surface was homogeneous. XPS analyses indicated that nitrogen atoms were actually incorporated into the LTO matrix framework. The substitution of nitrogen for oxygen in the thin film created more abundant cross-linking structures, which favored the higher mobility of lithium ions. The LTON had a high capacity of 290mAhg−1 at 0.1C, excellent rate capability of 160mAhg−1 at 5C and only ≈7% capacity loss after 100 cycles at 5C charge and discharge rate. These properties make this thin film electrode a promising candidate material for use in thin film lithium ion batteries.

Preparation and electrical properties of amorphous Li-Al-Ti-P-O thin film electrolyte

The electrical properties of amorphous thin solid films of Li1.3Al0.3Ti1.7 (PO4)3 (LATP) electrolyte deposited on stainless steel substrates via radio-frequency magnetron sputtering from LATP powder targets were studied. The results indicated that the LATP thin film electrolyte deposited in Ar-O2 atmosphere has a high ionic conductivity of 6.47×10−6Scm−1 and a low electronic conductivity of 2.34×10−14Scm−1. The easy fabrication of LATP thin films, high ionic conductivity together with the small electronic conductivity suggest that LATP thin films are promising as a candidate for solid electrolytes in all-solid-state thin film lithium batteries.

Doping Ga effect on ZnO radio frequency sputtered films from a powder target

Undoped ZnO and ZnO:Ga films have been radio frequency (RF) sputtered on glass substrates using powder targets. X-ray diffraction studies reveal that the films are polycrystalline with a hexagonal wurtzite structure and a preferential orientation along the c-axis. The (002) peak shift to lower 2θ values indicates that the films suffered compressive stress with Ga incorporation. The grain sizes are found in the range of 20–23nm showing a nanostructure. All the films are highly transparent (>85%) in the visible region and the optical band gap shows a blue shift with Ga incorporation up to 3wt.% then a red shift with further Ga content from 3.56 to 3.47eV due to band tail. Urbach energy increases from 0.06 to 0.15eV with Ga content revealing disorder increase in the lattice.Besides the near band emission peak, which shows the same trend for the optical band gap variation, Photoluminescence measurements show deep level emissions in the violet, blue and green regions.The electrical parameters were obtained with both optical reflectance based on the Drude free-electron model and the Hall method and similar tendencies were observed within the two methods. The highest figure of merit observed in this study was 3.57×10−3Ω−1 showing that the 3wt.% ZnO:Ga films are potentially attractive for application as transparent conductive oxide thin films in solar cells. RF sputtering from a powder target was found to be a simple and cost effective technique for the synthesis of ZnO thin films for potential applications in the renewable energy devices.

Preparation of mixed bismuth and iron thin films by pulsed laser deposition using powder targets

Bismuth iron garnet (Bi3Fe5O12) thin films, for use in magnetic optics, were prepared by a pulsed laser deposition method using Bi and Fe mixed powder targets in oxygen gas. The deposition rate of the film strongly depended on the target mixture. The X-ray diffraction and X-ray photoelectron spectroscopy results suggest that the prepared films were not Bi3Fe5O12 but Bi-rich films, because of the lower melting temperature of Bi (544 K) compared with that of Fe (1811 K).

Sputtering deposition of Al-doped zinc oxide thin films using mixed powder targets

Sputtering deposition generally uses high-density bulk targets. Such a fabrication process has various problems including deterioration of the material during heating and difficulty in mixing a large number of materials in precise proportions. However, these problems can be solved by using a powder target. In this study, we prepared Al-doped ZnO (AZO) as transparent conductive thin films by radio-frequency magnetron sputtering with powder and bulk targets. Both the powder and bulk targets formed crystalline structures. The ZnO (002) peak was observed in the X-ray diffraction measurements. The mean transparency and resistivity of the films prepared with the powder target were 82% and 0.548 Ω · cm, respectively. The deposition rate with the powder target was lower than that with the bulk target.

Preparation and characterisation of porous lithium titanate thin film by magnetron sputtering

This work introduces a facile solution method for preparation of porous Li4Ti5O12 (LTO) thin film electrode for lithium-ion batteries (LIBs). The porous LTO films were prepared by magnetron sputtering deposition using cubic spinel LTO powder target as a sputtering source. The microstructure and morphology of the LTO thin films annealed in air (LTO-air) was porous structured thin film. The LTO-air thin film electrode showed the excellent electrochemical performance. The capacity of LTO-air up to 81 μAh cm−2μm was at 10 μA cm−2, and capacity retention was 99% after 100 cycles at 10 μA cm−2. The porous structure features of thin film likely contributed to the good electrochemical performance of the LTO-air thin film. This research suggests that LTO thin films have the potential for the high energy storage electrode material for LIBs.

Highly luminescent metal organic framework Eu(TMA)(H2O)4 materials prepared by laser ablation technique in liquid

A highly luminescent metal organic framework Eu(TMA)(H2O)4 has been prepared by the laser ablation technique in liquid environment for the first time. The experiment set up consists of the ablation of europium oxide powder target in a solution of DMF/H2O (1:1), Trimesic acid (TMA) and NaNO3 with the second harmonic (λ=532nm) of a high power Nd:YAG laser. The XRD patterns and SEM measurement show that the complex is highly crystalline and presents a morphology of rod like shape, with a diameter in the range of 80–500nm, and its length ranges from one hundred nanometers to a few micrometers. The FT-IR measurements confirm that the complex has been obtained and the difference parameter between the asymmetric and symmetric infrared mode Δν=183cm−1 is an indication that the carboxyl oxygen is coordinated with Eu(III) in a bidentate bridge coordination form. Photoluminescence analysis shows that the Eu(TMA)(H2O)4 complexes shows sharp emissions characteristic of 5D0–7F0–4 transitions, suggesting the presence of only one site of symmetry around the europium ion and quantum yield of Φ=40%.

Fabrication and Characterization of the AZO/Ag/AZO Transparent Conductive Films Prepared by RF Magnetron Sputtering Using Powder Targets

Fabrication and Characterization of the AZO/Ag/AZO Transparent Conductive Films Prepared by RF Magnetron Sputtering Using Powder Targets

Parametric X-rays from a polycrystalline target

A theoretical description of parametric X-ray radiation (PXR) from a nanocrystal powder target is presented in terms of the orientation distribution function (ODF). Two models of ODF resulting in the analytical solution for the PXR intensity distribution are used and the characteristic features of this distribution are considered. A promising estimate of the number of the emitted photons is obtained for the case of a nanodiamond powder target using the parameters of ASTA Facility at Fermilab. The PXR spectra from polycrystal and single crystal targets are compared. The application scenarios of PXR from nanocrystals are discussed.

Properties and preparation of Li–La–Ti–Zr–O thin film electrolyte

Amorphous Li–La–Ti–Zr–O thin film electrolyte has been deposited on the tin-doped indium oxide (ITO)/glass substrate by radio frequency magnetron co-sputtering using Li0.33La0.56TiO3 (LLTO) and Li7La3Zr2O12 (LLZO) powder targets. The ionic conductivity and electronic conductivity of the Li–La–Ti–Zr–O thin film electrolyte are investigated at room temperature by AC impedance and I–V curve, respectively. The results show that the as-prepared amorphous Li–La–Ti–Zr–O thin film electrolyte has a high ionic conductivity of 2.83×10−6Scm−1 and a low electronic conductivity of 5.10×10−10Scm−1, and can be used as an electrolyte of all-solid-state thin film lithium batteries.

High entropy alloy thin films deposited by magnetron sputtering of powder targets

High entropy alloys (HEA) contain at least five principal elements in equimolar or near-equimolar ratios. These materials crystallize typically as a face-centered cubic (FCC), body-centered cubic (BCC) solid solution or as a mixture of these two crystal structures. AlCoCrCuFeNi thin films were deposited by magnetron sputtering of homemade pressed powder targets. Four targets with different compositions were sputtered under various conditions to modify the alloy composition. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to study the surface morphology and composition whereas X-ray diffraction and X-ray reflectivity provided information regarding the phase formation and density of the films. It is suggested that, when taking into account the atomic radii of the constituent elements, the sputter deposited alloy thin films can be topologically regarded as binary alloys of the form Al-(CoCrCuFeNi). If the concentration of the largest atom (Al) increases, a transition from FCC to BCC is noticed. This structure transition could be attributed to a critical lattice distortion.

Titanium Oxide Thin Film Preparation by Pulsed Laser Deposition Method Using Ti and TiO<sub>2</sub> Powder Target

Titanium Oxide Thin Film Preparation by Pulsed Laser Deposition Method Using Ti and TiO<sub>2</sub> Powder Target

Hard wear-resistant TiAlSiCN/MoSeC coatings with a low friction coefficient at room and elevated temperatures

TiAlSiCN and TiAlSiCN/MoSeC coatings are fabricated by magnetron sputtering of segmented SHS and compacted powder targets. The structure and composition of coatings are investigated by X-ray phase analysis, X-ray photoelectron spectroscopy, Raman spectroscopy, transmission electron microscopy, and glow-discharge optical emission spectroscopy. The TiAlSiCN coating is based on the fcc phase with crystallite size <15 nm; the crystallite size decreases under sputtering of TiAlSiCN and MoSeC segments in a ratio of 3: 1 and crystallites amorphized at a ratio of 2: 2. The MoSe2 phase is also found in TiAlSiCN/MoSeC coatings. According to the results of nanoindentation, the hardness of TiAlSiCN coatings is 40 GPa and that of TiAlSiCN/MoSeC coatings is 28 and 12 GPa at ratios of 3: 1 and 2: 2, respectively. The friction coefficient of TiAlSiCN coatings at room temperature is 0.75, it decreases to 0.05 after the introduction of MoSeC, and wear resistance of coatings increases as well. A low friction coefficient (<0.1) under tribological tests of TiAl-SiCN/MoSeC coatings with continuous heating is invariable up to 300°C.