Magnetron Sputtering

This research reveals the missing or often undisclosed experimental data on processing conditions of Cu(In,Ga)(S,Se)2 absorbers by the two-step sequential technique. Accordingly, by employing a one-variable-at-a-time approach-where each factor is exclusively changed with respect to a defined center point, we identified a handful of significant parameters which play the most significant role in an absorber's properties and consequently, prospective high-performing solar cells. This was done by analyzing their impact on a few most important metrics. Hence, the vast processing window with numerous factors and levels for development of Cu(In,Ga)(S,Se)2 by this method becomes constrained and feasible to optimize in future endeavours.

Polycrystalline Cu 2 ZnSnS 4 (CZTS) thin film has been grown on glass substrate by RF-magnetron sputtering at substrate temperature 573 K using a commercial target of same composition. Structural and optical properties of the grown thin film have been investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectroscopy and UV-vis spectroscopy. Detailed analysis of XRD data has showed that the as-grown CZTS thin film has keserite structure ( I , a = 5.4290 and c = 10.849Å) with preferred orientation along (112) plane. All the peaks observed in the XRD pattern have been accounted for kieserite structure, which shows the absence of additional phases such as elemental or binary or ternary systems in the grown film. SEM images recorded with different magnification have showed that the film has smooth and homogeneous surface with average crystallite size 100 nm. Raman spectrum recorded at room temperature has showed the dominant Raman shift at about 326 cm -1 which can be attributed to A 1 mode and confirms the formation of kieserite CZTS phase. From optical transmittance spectrum, the grown film is found to have direct band gap of ~1.51 eV. The above observations show that the material under investigation is suitable for solar cell application.

Swanepoel method is employed for spectroscopic determination of optical properties of Cu 3 N thin film using transmittance data. Investigated films have been deposited using reactive magnetron sputtering system. Deposition time was 9 to 21 min. Refractive index, absorption coefficient, and bandgap energy of the samples are determined. Thickness of the films is calculated by Swanepoel method, and result is compared with the thickness of the films measured by profilmeter. It is shown that Swanepoel method is a reliable way to calculate the optical constants of thin films when the transmittance spectrum of the film is influenced by wavelike patterns due to reflection of the probe beam from different interfaces.

Swanepoel method is employed for spectroscopic determination of optical properties of Cu 3 N thin film using transmittance data. Investigated films have been deposited using reactive magnetron sputtering system. Deposition time was 9 to 21 min. Refractive index, absorption coefficient, and bandgap energy of the samples are determined. Thickness of the films is calculated by Swanepoel method, and result is compared with the thickness of the films measured by profilmeter. It is shown that Swanepoel method is a reliable way to calculate the optical constants of thin films when the transmittance spectrum of the film is influenced by wavelike patterns due to reflection of the probe beam from different interfaces.

Swanepoel method is employed for spectroscopic determination of optical properties of Cu3N thin film using transmittance data. Investigated films have been deposited using reactive magnetron sputtering system. Deposition time was 9 to 21 min. Refractive index, absorption coefficient, and bandgap energy of the samples are determined. Thickness of the films is calculated by Swanepoel method, and result is compared with the thickness of the films measured by profilmeter. It is shown that Swanepoel method is a reliable way to calculate the optical constants of thin films when the transmittance spectrum of the film is influenced by wavelike patterns due to reflection of the probe beam from different interfaces.

Broadband extreme ultraviolet molybdenum/yttrium aperiodic multilayer analyzers were designed for polarization experiments in 8.5–11.7nm wavelength range. The multilayer analyzers were made using direct current magnetron sputtering and characterized using the soft x-ray polarimeter at BESSY-II facility. Measured s reflectivities at the Brewster angle are 5.5% for a multilayer designed for 8.5–10.1nm wavelength range and 6.1% for one designed for 9.1–11.7nm. The multilayers also exhibit high polarization degree up to 98.79%. In addition, the multilayer was also measured over 38°–52° angular range at the fixed wavelength of 10.2nm and the mean s reflectivity is 6.2%.

Different sputtering methods, viz. rf-diode, rf-magnetron, and dc-magnetron sputtering, have been used to increase the sensitivity of Co/Cu/Co/FeMn top spin valve systems by more than a factor of 2. This improvement is due to an enhanced magnetoresistive effect ΔR/R and a reduced anisotropy field Hk for the best sample. In the present paper the transport and magnetic properties are discussed in the context of microstructure and interfacial quality of the multilayers evaluated by comprehensive transmission electron microscopy and x-ray reflectometry investigations. The sample with the highest sensitivity (dc-magnetron sputtered) shows less structural defects and locally smoother interfaces than the other samples. Additionally it is shown that the ferromagnetic interlayer exchange field is not affected by the applied sputtering methods and can be well understood in terms of orange peel coupling.

Five-component Fe-based films containing 2 at % Ti, 1-2 at % B, 8-13 at % O, and 2-7 at % N were deposited by magnetron sputtering of the Fe(88-82)Ti(4-6)B(8-12) sintered targets. The sintered targets being a source of gaseousforming elements contaminate the films by impurity oxygen and nitrogen, which affect the chemical and phase composition of the films. As the oxygen and nitrogen contents in the films increase, the paramagnetic FeO phase appears along with a paramagnetic amorphous grain boundary phase. This fact, in turn, determines the effect of impurity O and N on the magnetic microstructure, quasi-static and microwave magnetic properties of the films. All the films are characterized by high coercive field (2-5.5 kA/m); as the impurity content increases, both saturation magnetization and relative permeability measured in a range up to 1 GHz decrease by an order of magnitude, namely, from 1.93±0.02 to 0.18±0.03 T and from 30±5 to 3 ± 1, respectively. The magnetron deposition of the films belonging to the Fe-Me IV X alloying system (where Me IV is Ti, Zr, or Hf; X is C, N, or B) should be performed under conditions that prevent a degradation of magnetic properties: in the absence of (1) contamination by residual gases, (2) formation of Fe-based paramagnetic phase and (3) a columnar structure.

In this study, anodized aluminum coupons are sputtered with titanium and successfully demonstrated as dye-sensitized solar cell (DSC) electrode substrates in both anode [back-illumination (BI)] and cathode [front-illumination (FI)] configurations. The FI DSCs were found to be significantly more efficient than the BI devices registering an average efficiency of 5.7 vs 2.6 pct. By comparison, the efficiency of benchmark cells built with fluorine-tin oxide-glass was 6.7 and 4.6 pct, respectively. The thickness of the titanium-sputtered film was varied from 0.85 to 1.1 lm with the latter providing a better average efficiency when used as a counter electrode. According to preliminary stability testing, the Ti-sputtered anodized aluminum-based DSC devices exhibited a significant reduction of their efficiency over a period of 10 days that was partly attributed to triiodide redox electrolyte reaction with the aluminum substrate. This points to the need for optimization of the sputtered-titanium coating microstructure in order to completely isolate the aluminum substrate from the liquid electrolyte.

We describe the deposition and characterization of epitaxial thin ®lms of the iron oxide haematite (a-Fe 2 O 3 ), a promising candidate for fundamental studies of exchange anisotropy as well as for high thermal stability applications. The ®lms were deposited by reactive dc magnetron sputtering. Structural characterization was by large-angle X-ray di raction and grazing-incidence re¯ectivity (with the scattering vector normal to the sample plane), in-plane grazing-incidence di raction (scattering vector in the sample plane) and re¯ection high-energy electron di raction. Optimized sputtering conditions result in good epitaxy both in the growth direction and in the plane, as well as very smooth surfaces.

Resumen -La necesidad de nuevos materiales con propiedades funcionales muy específicas y las herramientas para su conformación mecánica han encarecido enormemente muchos procesos de mecanizado y el costo de las piezas terminadas. Los recubrimientos superficiales permiten la obtención de las propiedades mecánicas requeridas sobre un material de base de bajo costo y fácil mecanizado. Los procesos de recubrimientos por plasma producen mejoras en el comportamiento de las superficies y tienen, entre otras, las ventajas siguientes: • Permiten obtener resultados de calidad superior y en muchos casos propiedades únicas frente a otras tecnologías convencionales. • No son contaminantes; hacen uso eficiente de la energía; son aplicables a mayor cantidad de materiales y tienen máxima seguridad operativa. • Se aplican al componente, herramienta o pieza cuando ya están terminados, es decir, forman parte de la última etapa de fabricación y, por lo tanto, influyen directamente sobre elementos que ya tienen alto valor agregado.

The effect of annealing in Ni doped Zinc oxide (ZnO) semiconductor thin films grown by a modified SILAR method is presented in this study. The XRD diffraction patterns reveal good crystalline quality without any appreciable changes from pure ZnO films and are genuinely polycrystalline with a hexagonal wurtzite structure. Scanning electron microscopic (SEM) investigation suggested that both the shape of the crystals and the texture of the films were highly influenced by the SILAR method. The SEM morphology shows the formation of vertical nanorods and interestingly, Ni doped ZnO shows fiber-like structures with good uniformity. These nano thin films are promising candidate for solar cells, photo detectors, and gas sensors.

Je remercie Monsieur Boyan Mutaftschiev pour m'avoir accueilli au laboratoire Maurice Letort et dans son équipe du "faisceau moléculaire", et pour avoir dirigé ces travaux. Je remercie Madame et Messieurs les membres du jury pour avoir accepté de faire partie de ma Commission d'Examen, et de consacrer ainsi un temps précieux à l'étude de ce rapport. Je remercie aussi Christophe de Beauvais pour m'avoir suivi et conseillé tout au long de cette thèse, tant au niveau théorique qu'expérimental et jusqu'à sa rédaction finale. Ce manuscrit lui doit beaucoup dans son contenu et dans sa forme, et je tiens à lui en rendre hommage . Je désire également exprimer ma reconnaissance à toutes les personnes de mon entourage scientifique et technique qui m'ont accompagné pendant ces années, et en particulier à Jean-Jacques Ehrhardt pour son soutien amical et attentif en tant que nouveau directeur du laboratoire, a Bernard Bigeard pour sa collaboration technique rigoureuse et compétente, et son efficacité lors des réparations de Cléopâtre, à Marc Alnot, Pascal Kissienne et Jacques Lambert pour leurs dépannages-éclairs en matière d'informatique, à Jean-Marie Génin pour sa lecture attentive du chapitre C.V, à l'ensemble des chercheurs et du personnel technique pour leur serviabilité et leur bienveillance, et en particulier à Georges Antoine et Jean-Pierre Mihé, à Marie-Rose Tempère et Christelle Launois pour leur disponibilité, leur gentillesse et leur efficacité jamais démenties, avec une mention spéciale à Christelle pour son assistance dans la frappe de ce rapport, à mon ami Ahmed Hamdi et tous les étudiants du laboratoire pour leur franche camaraderie. Je veux enfin remercier globalement tous les acteurs du laboratoire Maurice Letort, qui par leur caractère, leur humour et leur philosophie, ont su entretenir en son sein une atmosphère vivante et chaleureuse, au-delà des remous traversés par celui-ci. Mais je ne peux clore ce chapitre des remerciements sans rendre hommage à la simplicité et la gentillesse de la famille Moulin, dont la présence discrète assure au chercheur du soir (ou du dimanche) l'accueil d'un laboratoire toujours hospitalier.

La0.7Sr0.3MnO3 as a sensing material has shown an amazing potential for uncooled thermal imaging application. Here we report the fabrication of a La0.7Sr0.3MnO3 (LSMO) thin film thermistor on a Si wafer and explored two prime figure-of-merit such as temperature coefficient of resistance (TCR) and optical responsivity, which are very useful parameters to compare the performance with any thermal sensor. The LSMO films were deposited on a SrTiO3(STO) buffer layer with Si/SiO2 as a substrate, by a pulsed laser deposition (PLD) technique. The crystallinity and surface topography of the films were analyzed by X-ray diffraction (XRD) and atomic force microscopy (AFM). The fabricated device was then analyzed for its thermal and electrical characteristics to validate its suitability as an IR sensor. The fabricated device shows very sharp metal-to-insulator (TMI) phase transition temperature at 150 K and very high TCR of +4% K−1 and −4%K−1near 100 K and 200 K respectively, when the temperatur...

Thin films of rhenium trioxide (ReO 3 ) were produced by reactive DC magnetron sputtering from metallic rhenium target followed by annealing in the air in the range of temperatures from 200C to 350C. Nanocrystalline singlephase ReO 3 films were obtained upon annealing at about 250C. The thin films appear bright red in reflected light and blue-green in transmitted light, thus showing an optical transparency window in the spectral range of 475-525 nm. The film exhibits high conductivity, evidenced by macro-and nano-scale conductivity measurements. The longrange and local atomic structures of the films were studied in detail by structural methods as X-ray diffraction and X-ray absorption spectroscopy. The oxidation state (6+) of rhenium was confirmed by X-ray photoemission and Xray absorption spectroscopies. The nanocrystalline morphology of the annealed films was evidenced by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The obtained results allowed us to propose the mechanism of rhenium oxide conversion from the initially amorphous ReO x phase to cubic ReO 3 .

Ba 0.5 Sr 0.5 TiO 3 (BST) thin films were deposited by rf magnetron sputtering using a Ba 0.5 Sr 0.5 TiO 3 target in pure Argon on two electrodes (Pt and RuO 2 ) at room temperature. The interface formation between BST and bottom electrode (Pt or RuO 2 ) was investigated by XPS for thicknesses in the 1 to 50 nm range. The chemical composition of the BST layers can be modified by the electrode nature over the first five nanometers. A 1 h ex-situ annealing, under flowing oxygen at 600 °C, was necessary to obtain crystallized 150 nm thick BST films, as evidenced by XRD and TEM analysis.

Ti-Si-C-ON films were deposited by DC reactive magnetron sputtering using different partial pressure of oxygen (p O2 ) and nitrogen (p N2 ) ratio. Compositional analysis revealed the existence of two different growth zones for the films; one zone deposited under low p O2 /p N2 and another zone deposited under high p O2 /p N2 . The films produced under low p O2 /p N2 were deposited at a lower rate and presented a fcc structure, as well as, dense and featureless morphologies. The films deposited with high p O2 /p N2, consequently higher oxygen content, were deposited at a higher rate and developed an amorphous structure. The structural changes are consistent with the hardness and Young's modulus evolution, as seen by the significant reduction of the hardness and influence on the Young's modulus by increasing p O2 /p N2.

A 10 nm Fe/5 nm NiO/10 nm Co polycrystalline trilayer prepared by magnetron sputtering has been investigated by resonant magnetic reflectivity of linearly polarized soft x rays ͑transversal magneto-optical Kerr effect geometry͒ at the L 3 edges of Fe, Ni, and Co. The exchange coupling in the trilayer, introduced during synthesis, has been altered by cooling through the Ne ´el temperature T N of NiO at three different cooling fields H FC . We show that the chemical structure at the interfaces, the grain size and the magnetic properties of the trilayer are governed by factors such as successive heat treatment, magnetic field applied during synthesis and cooling through T N of NiO. Clear evidence for oxidation of Fe and Co states has been obtained, suggestive for the formation of mixed oxides at the Fe/NiO and NiO/Co interfaces. Oxidized Fe and Co are found to carry a net magnetic moment, which couples to the moments of the metallic states. We find that the coupling between oxidized and metallic Co spins is ferromagnetic, whereas the coupling between oxidized and metallic Fe spins is antiferromagnetic. We observe the presence of two types of excess Ni spins. A rigid excess Ni magnetic moment is induced at the interface during synthesis as follows from the strong asymmetry of the x-ray Kerr loops of the oxidized Co spins at H FC ϭ0 Oe and metallic Co spins at H FC ϭ240 Oe. Heat treatment leads to appearence of a soft excess Ni magnetic moment, which is ferromagnetically coupled to the metallic Fe and Co spins and exhibits a conventional hysteresis loop. Competing interactions lead to frustrated magnetization at the NiO/Fe interface and cause a tilt of the Fe spins away from the direction of applied magnetic field. This manifests itself in the presence of characteristic humps in the Fe Kerr loops.

Using numerical optimization algorithm, non-periodic Mo/Si, Mo/Be, and Ni/C broad angular multilayer analyzers have been designed. At the wavelength of 13 nm and the angular range of 45~49 o , the Mo/Si and Mo/Be multilayer can provide the plateau s-reflectivity of 65% and 45%, respectively. At 5.7 nm, the s-reflectivity of Ni/C multilayer is 16% in the 44~46 o range. The non-periodic Mo/Si broad angular multilayer was also fabricated using DC magnetron sputtering, and characterized using the soft X-ray polarimeter at BESSY. The s-reflectivity is higher than 45.6% over the angular range of 45~49 o at 13 nm, where, the degree of polarization is more than 99.98%.

Cr-Ti multilayers with ultrashort periods of 1.39-2.04 nm have been grown for the first time as highly reflective, soft-x-ray multilayer, near-normal incidence mirrors for transition radiation and C ˇherenkov radiation x-ray sources based on the Ti-2p absorption edge at E ϭ 452 eV ͑ ϭ 2.74 nm͒. Hard, as well as soft, x-ay reflectivity and transmission electron microscopy were used to characterize the nanostructure of the mirrors. To achieve minimal accumulated roughness, improved interface flatness, and to avoid intermixing at the interfaces, each individual layer was engineered by use of a two-stage ion assistance process during magnetron sputter deposition: The first 0.3 nm of each Ti and Cr layer was grown without ion assistance, and the remaining 0.39-0.72 nm of the layers were grown with high ion-neutral flux ratios ⌽ ˙͑⌽ Ti ϭ 3.3, ⌽ Cr ϭ 2.2͒ and a low energy E ion ͑E Ti ϭ 23.7 and E Cr ϭ 21.2͒, ion assistance. A maximum soft-x-ray reflectivity of R ϭ 2.1% at near-normal incidence (ϳ78.8°) was achieved for a multilayer mirror containing 100 bilayers with a modulation period of 1.379 nm and a layer thickness ratio of ⌫ ϭ 0.5. For a polarizing multilayer mirror with 150 bilayers designed for operation at the Brewster angle, 45°, an extinction ratio, R s ͞R p , of 266 was achieved with an absolute reflectivity of R ϭ 4.3%.

The electrospinnability of concentrated aqueous solutions of glucose, fructose and sucrose was combinatorially studied by physicochemical and rheological characterisation methods, and by subsequently examining the fibre morphology via scanning electron microscopy. Furthermore, the significance of intermolecular forces (van der Waals versus hydrogen bonding) in the electrospinnability of saccharides was investigated as a function of the substitution of sucrose (e.g., octa-O-acetyl sucrose and octa-O-methyl sucrose), using an aqueous sucrose solution as the control. Moreover, electrospinnability models based on chain entanglement and visco-elasto-capillary theories were compared with experimental results. Visco-elasto-capillary theory showed a better relationship to experimental data, suggesting that longer relaxation times or the capacity to remain electrically stressed for longer periods of time, correlated to improved electrospinnability.

It has been proposed that hydrogen bonding plays a role in promoting the electrospinnability of some materials. In this study, the role of non-covalent interactions in the electrospinnability of 2-hydroxypropyl-β-cyclodextrin (2HP-β-CD) was investigated by varying the physical-chemical properties the solvents. The rheological behaviour of a peroxideaqueous/acetone-ethanol/NaHCO3 solution and an aqueous urea solution, as a function of aqueous 2HP-β-CD concentration, was compared. The rheological behaviour of 2HP-β-CD solutions was characterized by a frequency-independent stress relaxation plateau such as that observed in cross-linked polymer networks and reversible polymer gels with non-linear viscoelasticity. We conclude that the electrospinnability of 2HP-β-CD is, as evidenced by the changes in the morphology of the electrospun 2HP-β-CD materials, in agreement with other related studies on the electrospinning of Cyclodextrins. Also, the electrospinnability of 2HP-β-CD does appear to be related to the physical-chemical properties of the solvent systems.

This study presents an in-depth analysis of the synthesis and characterization of chromium oxynitride CrO x N y films fabricated on silicon and fused silica substrates by radiofrequency magnetron sputtering, highlighting their potential application as electrodes in supercapacitors. By systematically varying the nitrogen flow rates during deposition, we achieved a tunable modification of the films' structural, electronic, and optical properties, including a significant range in bandgap energies from 1.51 to 2.85 eV. The thin films show exceptional electrochemical performance, showcasing a highly impressive areal capacitance of 75 mF/cm 2 and remarkable stability after 5000 cycles retaining 98.2% of the capacitance charge, and maintaining coulombic efficiency of 97.5% in 1 M H 2 SO 4 electrolyte. These results show the impact of growth conditions on characteristics of the films and their implications for enhancing supercapacitor performance. The combination of detailed structural, electronic, and electrochemical analyses establishes CrO x N y thin films as a versatile and promising candidate for advanced energy storage applications, offering insights into the design of supercapacitive devices with improved efficiency and durability.

A thermally oxidized TiO 2 or Nb 2 O 5 film equipped with a top Pd film electrode and a bottom Ti or Nb plate electrode (Pd/MO(n)/M, MO: oxide film, M: metal plate, n: annealing temperature (°C)) has been investigated as a diode-type H 2 sensor under air or N 2 atmosphere. Pd/TiO 2 (n)/Ti sensors showed relatively poor H 2 sensing properties in air, in comparison with Pd/anodic-TiO 2 (n)/Ti sensors constructed with an anodized TiO 2 film equipped with a top Pd film electrode and a bottom Ti plate electrode, which were reported in our previous studies. On the other hand, Pd/Nb 2 O 5 (n)/Nb sensors showed relatively larger H 2 response with fast response and recovery speeds than Pd/TiO 2 (n)/Ti sensors in air under high forward bias conditions. A Pd/Nb 2 O 5 (450)/Ti sensor, which was fabricated by radio-frequency magnetron sputtering of Nb metal on a Ti substrate followed by thermal oxidation at 450°C, showed the largest H 2 response and relatively fast response and recovery speeds in air, among the sensors tested. In addition, H 2 response of the Pd/Nb 2 O 5 (450)/Ti sensor in air was much lower than that in N 2 , but the logarithm of H 2 response was almost proportional to the logarithm of H 2 concentration in a wide range of H 2 concentration (10~8000 ppm) in air, and the H 2 sensitivity in air was much higher than that in N 2 .

The involvement of plasmas in deposition processes opens the possibility for non-equilibrium processes including atomic scale heating by ions and electrons. This can be very beneficial from several points of view, including, but not limited to, a reduction of the requirements for conventional substrate heating, the possibility to deposit films on temperature-sensitive substrates, the formation of metastable or otherwise unattainable phases, and the combination of deposition and etching effects. Non-equilibrium heating implies transient (sub-picosecond to picoseconds) and highly localized (nanometer-squared) events associated with the arrival of energetic particles from the plasma. These particles carry kinetic and potential energies to the substrate or film surface. While conventional heating drives the system always toward equilibrium, non-equilibrium heating events involve competing effects of defect generation (affected by momentum transfer) and annealing (by localized heating). Non-equilibrium heating is complex and enables the formation of metastable, non-equilibrium phases. The most often used approach to control the kinetic energy of ions is tuning the difference between plasma and surface potentials, i.e., using suitable substrate or plasma bias. When the kinetic ion energy exceeds the displacement energy, film growth can occur under the surface (very shallow ion implantation or "subplantation"), which is utilized, for example, in the deposition of diamond-like carbon and of metastable cubic phases of ternary nitrides. Besides kinetic energy, potential energy is brought to the growing film, especially if the arriving ion flux contains multiply charged ions, which is common in cathodic arc deposition. The extremely fast and localized heating events accumulate and thereby lead to an increase of the global film surface temperature. The relation of equilibrium and non-equilibrium heating is captured by generalized temperature and energy axes in structure zone diagrams. This review focuses on non-equilibrium heating processes by ions and electrons.

Ever since they have been studied, gas discharges have been classified by their visual appearance as well as by their current and voltage levels. Glow and arc discharges are the most prominent and well-known modes of discharges involving electrodes. In a first approximation, they are distinguished by their current and voltage levels, and current-voltage characteristics are a common way to display their relations. In this review, glow discharges are defined by their individual electron emission mechanism such as secondary electron emission by photons and primary ions, and arcs by their respective collective mechanism such as thermionic or explosive electron emission. Emitted electrons are accelerated in the cathode sheath and play an important role in sustaining the discharge plasma. In some cases, however, electron emission is not important for sustaining the plasma, and consequently we have neither a glow nor an arc discharge but a third type of discharge, the ohmic discharge. In part 1 of this review, these relationships are explained for quasi-stationary discharges, culminating with updated graphical presentations of I-V characteristics (Figs. 15 and 16). In part 2, further examples are reviewed to include time-dependent discharges, discharges with electron trapping (hollow cathode, E Â B discharges) and active anode effects.

Due to the abundance and low cost of exchanged metal, sodium-ion batteries have attracted increasing research attention for the massive energy storage associated with renewable energy sources. Nickel oxide (NiO) thin films have been prepared by magnetron sputtering (MS) deposition under an oblique angle configuration (OAD) and used as electrodes for Na-ion batteries. A systematic chemical, structural and electrochemical analysis of this electrode has been carried out. The electrochemical characterization by galvanostatic charge–discharge cycling and cyclic voltammetry has revealed a certain loss of performance after the initial cycling of the battery. The conversion reaction of NiO with sodium ions during the discharge process to generate sodium oxide and Ni metal has been confirmed by X-ray photoelectron spectra (XPS) and micro-Raman analysis. Likewise, it has been determined that the charging process is not totally reversible, causing a reduction in battery capacity.

The optimization of the catalysts incorporated to the electrodes for anion exchange membrane water electrolysers is a key issue to maximize their performance through the improvement of the oxygen evolution reaction (OER) yield. In this work, we show that the modification of the microstructure and the chemical properties of a mixed coppercobalt oxide anode may contribute to increase the activity of this reaction. For this purpose, the OER has been systematically studied, either in a half cell or in a membrane electrode assembly configuration, as a function of the chemical composition, load and agglomeration degree of the catalysts used as electrodes, as prepared by magnetron sputtering deposition in an oblique angle configuration. Chemical analysis by X-ray absorption spectroscopy and electrochemical analysis by cyclic voltammetry and impedance spectroscopy have shown that cobalt-copper mixed oxide catalysts with a 1.8 Co/Cu atomic ratio and about one micron equivalent thickness maximizes the cell performance. The chemical, structural and microstructural factors controlling the final behaviour of these anodes and accounting for this maximization of the reaction yield are discussed on the basis of these characterization results and as a function of preparation variables of the electrodes and operating conditions of the cell.

Based on an already tested laboratory procedure, a new magnetron sputtering methodology to simultaneously coat two-sides of large area implants (up to ~15 cm2) with Ti nanocolumns in industrial reactors has been developed. By analyzing the required growth conditions in a laboratory setup, a new geometry and methodology have been proposed and tested in a semi-industrial scale reactor. A bone plate (DePuy Synthes) and a pseudo-rectangular bone plate extracted from a patient were coated following the new methodology, obtaining that their osteoblast proliferation efficiency and antibacterial functionality were equivalent to the coatings grown in the laboratory reactor on small areas. In particular, two kinds of experiments were performed: Analysis of bacterial adhesion and biofilm formation, and osteoblasts–bacteria competitive in vitro growth scenarios. In all these cases, the coatings show an opposite behavior toward osteoblast and bacterial proliferation, demonstrating that the propo...

This paper reports a novel cholesterol biosensor based on nanostructured platinum (Pt) thin films prepared by Magnetron Sputtering (MS) in an oblique angle (OAD) configuration. Pt thin films were deposited onto a gold screen-printed electrode and characterized using Rutherford Back Scattering (RBS), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Cyclic Voltammetry (CV), X-ray Photo-electron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and wetting analysis. Our results confirmed that the film is highly porous and formed by tilted nanocolumns, with an inclination of around 40º and a total thickness of 280 nm. XRD and CV analysis confirmed the polycrystalline nature of the Pt thin film. Cholesterol oxidase (ChOx) was covalently immobilized using a bioinspired polymer, polydopamine (PDA), via Schiff base formation and Michael-type addition. After being immobilized, ChOx displayed an apparent activation energy of 34.09 kJ mol -1 and a Michaelis constant (K M ) equal to 3.65 mM, confirming the high affinity between ChOx and cholesterol and the excellent ability of the PDA film for immobilizing biological material without degradation. Under optimized working conditions our biosensor presented a sensitivity of 14.3 mA M -1 cm -2 (R 2 :0.999) with a linear range up to 0.5 mM and a limit of detection of 10.5 µM (S/N = 3). Furthermore the biosensor exhibits a fast response (< 8 s), good anti-interference properties and high stability after relatively long-term storage (2 months).

Uniform, highly porous, columnar thin films incorporating YSZ and NiO prepared by magnetron sputtering with deposition at glancing incidence exhibited stoichiometries close to that of the Y-Zr-Ni sputter target. Characterization by means of SEM, XRD, XPS and RBS revealed that the uniformly distributed nickel component in the as-deposited films consisted of NiO, and that the YSZ component was essentially amorphous. Annealing such films at 850º C in hydrogen resulted in crystallization of the YSZ phase with preservation of the columnar morphology, while the NiO underwent reduction to metallic Ni, which partially segregated to the film surface. The hydrogenannealed thin film anodes exhibited high conductivity, comparable to that of conventionallyprepared anodes, in both hydrogen and hydrogen/water mixtures at temperatures relevant to SOFC operation. They were also robust against strain-induced separation from the substrate under limited thermal cycling in both oxidizing and reducing atmospheres and are promising candidates for use as anodes in their own right and as strain-accommodating buffer layers between conventional anodes and the electrolyte for use in SOFC applications.

We present the thin films growth and study of manganese doped zinc nitride by RF/DC magnetron sputtering to investigate the optimum doping concentration that can result in the material to be dilute magnetic semiconductor. We studied the grown films using spectrophotometry, X-ray diffraction, Hall effect measurement, atomic force microscopy and X-ray photoelectron spectroscopy. We observed the effect of manganese doping concentration on the surface morphology, optical, electronic, and magnetic properties of the films. The grown films were found to be polycrystalline in nature. However, a prominent Zn 3 N 2 (411) peak was present in all the films. Bandgap of the grown films was dependent on the manganese concentration in the films, a red-shift in the bandgap was observed for Mn doped samples. Hall effect measurement revealed that all the grown films were ntype semiconductors and carrier density of the films was lower for manganese doped films whereas Hall mobility was higher for Mn doped samples. Manganese was found to be in the second (Mn +2) and third (Mn +3) oxidation states for low doped samples. But as the concentration of manganese in the films was increased the samples were found to be in 3rd and 4th oxidation states. Manganese oxidation state was directly related to the magnetism of the samples. A negative magnetoresistance was found for samples with lower manganese concentration but higher doped samples exhibited zero or positive magnetoresistance.

The technique of thermal vacuum deposition of Ge onto GaAs substrates has been used for obtaining nanocrystalline Ge films. Nanocrystalline character of the films is confirmed by atomic force microscopy of their surface and by the data of Raman light scattering. The most probable size of the nanocrystallites forming the films decreases monotonically with decreasing their thickness. And raise of the deposition temperature results in their enlargement. Electro conductivity of such films proves to be high enough (resistivity of 1-10 Ohm cm at room temperature) and has character of variable range hopping conduction of the Mott's type. The hops, presumably, take place through the localized states connected with the grain boundaries.

As an origin of degradation of remnant polarization in Pt/ BaTiO 3 / Pt capacitor structure, an interfacial layer formed at the interface of BaTiO 3 film and a Pt bottom electrode is considered. BaTiO 3 films were deposited on two types of bottom electrodes ͑La 0.5 Sr 0.5 CoO 3 and Pt͒ by the radio frequency magnetron sputtering method and both capacitors showed a microstructural similarity with strong preferred orientations. However, a Pt/ BaTiO 3 /La 0.5 Sr 0.5 CoO 3 capacitor exhibited a saturated hysteresis loop with the remnant polarization ͑2P r ͒ of 6 C/cm 2 , and for the Pt/ BaTiO 3 / Pt structure, the polarization-voltage curve revealed a linear dielectric characteristic. From a cross-sectional high-resolution transmission electron microscope analysis of the Pt/ BaTiO 3 / Pt capacitor showing the linear dielectric property, an interfacial layer with an amorphous structure as well as a multidomain structure in the interior of the BaTiO 3 film were observed. It is concluded that the interfacial layer might help degradation of polarization and its origin can be classified as being extrinsic.

As an origin of degradation of remnant polarization in Pt/ BaTiO 3 / Pt capacitor structure, an interfacial layer formed at the interface of BaTiO 3 film and a Pt bottom electrode is considered. BaTiO 3 films were deposited on two types of bottom electrodes ͑La 0.5 Sr 0.5 CoO 3 and Pt͒ by the radio frequency magnetron sputtering method and both capacitors showed a microstructural similarity with strong preferred orientations. However, a Pt/ BaTiO 3 /La 0.5 Sr 0.5 CoO 3 capacitor exhibited a saturated hysteresis loop with the remnant polarization ͑2P r ͒ of 6 C/cm 2 , and for the Pt/ BaTiO 3 / Pt structure, the polarization-voltage curve revealed a linear dielectric characteristic. From a cross-sectional high-resolution transmission electron microscope analysis of the Pt/ BaTiO 3 / Pt capacitor showing the linear dielectric property, an interfacial layer with an amorphous structure as well as a multidomain structure in the interior of the BaTiO 3 film were observed. It is concluded that the interfacial layer might help degradation of polarization and its origin can be classified as being extrinsic.

This study presents different approaches to increase the sensing area of NiO based semiconducting metal oxide gas sensors. Micro-and nanopatterned laser induced periodic surface structures (LIPSS) are generated on silicon and Si/SiO2 substrates. The surface morphologies of the fabricated samples are examined by FE SEM. We select the silicon samples with an intermediate Si3N4 layer due to its superior isolation quality over the thermal oxide for evaluating the hydrogen and acetone sensitivity of a NiO based test sensor.

Effect of rapid thermal annealing temperature on the dispersion of silicon nanocrystals (Si-NC's) embedded in SiO2 matrix grown by atom beam sputtering (ABS) method is reported. The dispersion of Si NCs in SiO 2 is an important issue to fabricate high efficiency devices based on Si-NC's. The transmission electron microscopy studies reveal that the precipitation of excess silicon is almost uniform and the particles grow in almost uniform size upto 850 C. The size distribution of the particles broadens and becomes bimodal as the temperature is increased to 950 C. This suggests that by controlling the annealing temperature, the dispersion of Si-NC's can be controlled. The results are supported by selected area diffraction (SAED) studies and micro photoluminescence (PL) spectroscopy. The discussion of effect of particle size distribution on PL spectrum is presented based on tight binding approximation (TBA) method using Gaussian and log-normal distribution of particles. The study suggests that the dispersion and consequently emission energy varies as a function of particle size distribution and that can be controlled by annealing parameters.

TiN/TiAlN multilayers were deposited by radio frequency, r.f., reactive magnetron sputtering by using titanium and aluminum targets with 10 cm diameter and 99.99% purity in an argon/nitrogen atmosphere, applying a substrate temperature of 300 °C. WC inserts were used as substrates to improve the mechanical and tribological properties of TiN/TiAlN multilayered coatings compared to other types of coatings like TiAlN monolayers and to manage greater efficiency of these coatings in different industrial applications, such as machining, and extrusion. Their physical, mechanical, and tribological characteristics were investigated, including cutting tests with AISI 4340 hardened steel (50 HRC) to assess wear as a function of the period and number of bilayers. A comparison of the properties of TiCN-Al2O3-TiN monolayers coatings and the [TiN/TiAlN]300 multilayers with individual layer thicknesses of 10 nm revealed a decrease of flank wear (around 33%) for [TiN/TiAlN]300 multilayers and a reduction of flank wear (around 13%) for coatings with 300 layers when is compared with [TiN/TiAlN]200 coatings. They also showed better machining properties onto hardened AISI 4340 steel pieces, when compared to uncoated WC inserts. These results open the possibility of using [TiN/TiAlN] multilayers as new coatings for tool machining with excellent industrial performance.

A new cyclotron laboratory for radioisotope production and multi-disciplinary research is under construction in Bern and will be operational in 2012. A commercial IBA 18 MeV proton cyclotron, equipped with a specifically conceived 6 m long external beam line, ending in a separate bunker, will provide beams for routine 18 F production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building which hosts physics laboratories, four GMP radiochemistry and radio-pharmacy laboratories, offices and two floors for patient treatment and clinical research activities. This project is the result of a successful collaboration among the University Hospital in Bern (Inselspital), the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. Furthermore, the establishment of a proton therapy centre on the campus of Inselspital is in the phase of advanced study.

The combination of high strength and high radiation damage tolerance in nanolaminate composites can be achieved when the individual layers in these composites are only a few nanometers thick and contain special interfaces that act both as obstacles to slip, as well as sinks for radiation-induced defects. The morphological and phase stabilities and strength and ductility of these nano-composites under ion irradiation are explored as a function of layer thickness, temperature and interface structure. Magnetron sputtered metallic multilayers such as Cu-Nb and V -Ag with a range of individual layer thickness from approximately 2 nm to 50 nm and the corresponding 1000 nm thick single layer films were implanted with helium ions at room temperature. Cross-sectional Transmission Electron Microscopy (TEM) was used to measure the distribution of " helium bubbles and correlated with the helium concentration profile measured vis ion beam analysis techniques to obtain the helium concentration at which bubbles are detected in TEM. It was found that in multilayers the minimum helium concentration to form bubbles (approximately I nm in size) that are easily resolved in through-focus TEM imaging was several atomic %, orders of magnitude higher than that in single layer metal films. This observation is consistent with an increased solubility of helium at interfaces that is predicted by atomistic modeling of the atomic structures of fcc-bcc interfaces. At helium concentrations as high as 7 at.%, a uniform distribution of I nm diameter bubbles results in negligible irradiation hardening and loss of deformability in multi layers with layer thicknesses of a few nanometers. The control of atomic structures of interfaces to produce high helium solubility at interfaces is crucial in the design of nano-composite materials that are radiation damage tolerant. Reduced radiation damage also leads to a reduction in the irradiation hardening, particularly at layer thickness of approximately 5 run and below. The strategies for design of radiation-tolerant structural materials based on the knowledge gained from this work will be discussed. This research isfunded by US DOE, Office of Basic Energy Sciences.

We report on the synthesis of epitaxial ͑single-crystal-like͒, nanotwinned Cu films via magnetron sputtering. Increasing the deposition rate from 1 to 4 nm/s decreased the average twin lamellae spacing from 16 to 7 nm. These epitaxial nanotwinned Cu films exhibit significantly higher ratio of hardness to room temperature electrical resistivity than columnar grain ͑nanocrystalline͒, textured, nanotwinned Cu films.

The first results of RF tests on a single cell copper niobium cavity operating at 1.5 GHz are presented .l The cavity was obtained by spinning an OFHC copper sheet in half cups and tubes. The cavity's components are welded together under vacuum; the so obtained cavity was niobium coated by using a scaled version (to our dimension) of the magnetron sputtering system developed at CERN for S/C cavities operating at 350 and 500 MHz. The results of our first tests on two cavities, together with the ancillarry measurements performed on several Niobium samples are presented.

Thin tungsten films were prepared by sputtering of pure tungsten in a cylindrical magnetron device. The XRD-patterns of tungsten films deposited at 3.5 Pa argon pressure regularly exhibited only a very broad signal centered at 2uf408-a distinctive mark of amorphous metals and alloys. The grain size of such amorphous-like tungsten material was estimated to be approximately 2 nm, while SAXS measurements yield a radius of gyration of 1.4 nm. Its thermal coefficient of the electric resistivity at room temperature was negative-a characteristic feature of amorphous metals and alloys. Thermal stability of the amorphous-like tungsten films was investigated by isochronal heating up to 720 8C in vacuum, with continuous monitoring of electric resistivity. The obtained results indicate that amorphous-like tungsten is thermally stable up to 450 8C.

In this work we report on a self-assembled growth of a Ge quantum dot lattice in a single 600-nm-thick Ge+ Al 2 O 3 layer during magnetron sputtering deposition of a Ge+ Al 2 O 3 mixture at an elevated substrate temperature. The self-assembly results in the formation of a well-ordered three-dimensional body-centered tetragonal quantum dot lattice within the whole deposited volume. The quantum dots formed are very small in size ͑less than 4.0 nm͒, have a narrow size distribution and a large packing density. The parameters of the quantum dot lattice can be tuned by changing the deposition parameters. The self-ordering of the quantum dots is explained by diffusion-mediated nucleation and surface-morphology effects and simulated by a kinetic Monte Carlo model.

In this article, we present an investigation of (Ge + SiO2)/SiO2 multilayers deposited by magnetron sputtering and subsequently annealed at different temperatures. The structural properties were investigated by transmission electron microscopy, grazing incidence small angles X-ray scattering, Rutherford backscattering spectrometry, Raman, and X-ray photoelectron spectroscopies. We show a formation of self-assembled Ge clusters during the deposition at 250°C. The clusters are ordered in a three-dimensional lattice, and they have very small sizes (about 3 nm) and narrow size distribution. The crystallization of the clusters was achieved at annealing temperature of 700°C.

Most modern architectural glazing are coated with at least one low emissivity layer stack. As a consequence of deploying those coatings, the heat transfer through the glazing can be significantly minimized. The desired heat-insulating properties result from the low emissivity in the infrared (IR) achieved by employing a thin metal film. Consequently, the majority of industrially fabricated low emissivity coatings on glass feature a layer stack including a thin silver film. DC magnetron sputtering is the preferred fabrication process in the architectural glazing industry for the deposition of low emissivity films due to the inherent advantages of this fabrication process like the homogeneous and time-efficient coating of large glass substrates. Thus, all layers discussed throughout this work are deposited by magnetron sputtering. To improve the efficiency of these coatings, the emissivity in the infrared needs to be decreased. This is equivalent to a maximization of the IR reflectance. Due to a fundamental link between the IR reflectance and the electrical resistance, the intended efficiency improvement can be achieved by a reduction of the electrical resistance of the silver film. The application of seed layers, namely ZnO, is a known method to decrease the resistance. In this context, the zinc oxide is used as a template to tailor the texture of silver thin films. Hence, one goal of the present work is to investigate the corresponding interface of the standard Ag/ZnO system to improve the understanding of this layer stack and to identify ways to obtain silver thin films with an improved structural quality in the thickness range between 8 nm to 12 nm. In particular one of the main objectives is the analysis of the epitaxial relationship between Ag and ZnO. Hence, various analysis techniques are employed to characterize and gain new insights about this system. Primarily, these techniques comprise electrical and structural characterization methods to correlate the film resistance with the structural quality of the Ag film and its relation to the substrate. To this end, different transport measurements are utilized including temperature dependent resistance measurements, whereas the structural characterization focuses on x-ray diffraction and transmission electron microscopy. In addition, the influence of alternative seed layers on silver thin films is analyzed. Two suitable approaches for the modification of the silver structure have been identified and were tested. The first approach features the integration of an additional seed layer, namely NiO, whereas the second one is based on using hydrogen-passivated, (111) oriented silicon (HF-etched Si) v Abstract substrates for the silver deposition. In both cases, the focus is on the interplay between seed layer and functional silver film. Particularly, it has been analyzed whether the silver structure and the electrical properties can be improved by these alternative seed layers. In detail, it has been also tested if the texture can be changed and whether the different seed layers have a pronounced impact on the percolation limit of the silver thin film or not.

This work reports the process used to manufacture CdS/CdTe thin film solar cells at the Instituto Militar de Engenharia (IME). The procedure consists of sequentially depositing several layers onto a glass substrate, config- ured as glass/TCO/CdS/CdTe/Au. Analysis of the individ- ual layers showed that the films had the minimum re- quirements to yield efficient devices. The use of different TCOs did not improve the device efficiency, probably due to other more important loss mechanisms. The available system in the laboratory for the measurement of photo- voltaic parameters yielded values near to the ones meas- ured at NREL. The maximum efficiency of 4.4% is low compared with the worldwide record of 16.5%, but it can probably be improved by optimizing some steps of the manufacturing process such as the contact to CdTe and the thickness of the CdS layer.

CdTe thin films are used as absorber layer in CdS/CdTe solar cells. The microstructure of this absorber layer plays a fundamental role in photovoltaic conversion and can be controlled by the deposition parameters used during the film growth. In this work, CdTe thin films were deposited by the CSS method onto glass substrates previously covered with In2O3:Sn. The effects of pressure, source temperature and substrate temperature on the microstructural properties of the films were studied. The properties were mainly influenced by the pressure, the presence of oxygen in the reaction chamber, and the substrate temperature. For films deposited under an argon atmosphere, an increase in grain size and a reduction of the texture were observed as the pressure and substrate temperature were increased. The introduction of oxygen in the atmosphere led to a decrease in the deposition rate and affected the microstructure and composition of the film. Films deposited under an argon-oxygen atmosphere...

Zinc oxide (ZnO) thin films are fabricated using several techniques. Among the numerous fabrication methods, the radio frequency (RF) magnetron sputtering method is industrially adopted for deposition of homogeneous ZnO films on large areas due to advantages such as, high deposition rates, better reproducibility, high stability, good adhesion to substrate, uniformity in thickness and composition, and easy control of the composition of the films, compared to the other techniques . Laser processing of materials involves their exposure to rapid and localized energy, which creates conditions of electronic and thermodynamic non-equilibrium. The laser induced heat can be localized in space and time, enabling excellent control over the manipulation of materials. Laser irradiation technique is used on thin films as an efficient method to improve the crystalline quality and increase the electron donors. Also, laser irradiation has several advantages, including fast crystallization at room te...