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ZnO thin films are synthesized by an ultrasonic spray pyrolysis method, with the deposition temperature in a range between 250–450 °C. The obtained thin films are analyzed by X‐ray diffraction (XRD), atomic force microscopy (AFM), and photoluminescence (PL). The samples are used in a photocatalytic experiment to compare the degradation efficiency by methylene blue decomposition under UV irradiation. XRD patterns confirm a polycristalline wurtzite structure with preferred orientation along the (002) plane. AFM images reveal an important change in the shape and size of the grains constituting the surface. The roughness values are in the range of 17–93 nm. Thickness values of thin films deposited at 250, 350, and 450 °C are ≈0.9, 2.3, and 1.4 µ, respectively. From PL characterization, the spectra are found to be sensitive to the deposition temperature, where emission peaks with different forms and intensities are observed. One peak at 389 nm is attributed to the recombination of free excitons, and other peaks between 403–522 nm correspond to violet, blue, and green emissions indicating the presence of Zn vacancies, Zn interstitials, and oxygen vacancies, respectively, in the ZnO structure. The photocatlytic results show that the best photocatalytic efficiency of 88% is achieved by ZnO thin film deposited at 450 °C. [ABSTRACT FROM AUTHOR]

Zirconium nitride films are deposited onto stainless steel AISI 316L and silicon (100) by radio frequency magnetron sputtering at different nitrogen flow ratios [N2/(Ar+N2)] varied between 0 and 0.25). Scanning electron microscope, atomic force microscopy, X‐ray diffraction (XRD), and Raman are used to investigate the surface morphology and microstructure of the thin films. The mechanical and electrochemical properties of all coatings are evaluated and compared with the uncoated AISI 316L to explore the efficiency of surface modification. The XRD and Raman analysis show that all the films are crystalline. This shows that the increased nitrogen content leads to a transformation from hexagonal α‐Zr phase to cubic c‐Zr and then to mixed α‐Zr and face centered cubic c‐ZrN phases. The films deposited with nitrogen flow ratio of 0.2 show the highest hardness of 32.2 GPa. Using the potentiodynamic polarization method, the corrosion behavior of the films is studied in Hank's solution. The comparison between uncoated and coated substrates shows a decrease in corrosion current density for all coated samples. [ABSTRACT FROM AUTHOR]

ZrO2 thin films were deposited on 316L stainless steel substrate by a radio-frequency magnetron sputtering system. The substrate bias voltage, the working gas rate and the reactive gas fraction in the gas mixture were varied. These variations produce a variation in the deferent properties of the obtained films. The deposited films were characterized by X-Rays Diffraction, Atomic Force Microscopy, nano-indentation and potentiodynamic polarization. The experimental results show that the film thickness and the roughness of the films are highly influenced by the plasma parameters. XRD results show that the monoclinic phase is predominant in unbiased deposited films. The best anti-corrosion performance and hardness were obtained for ZrO2 deposited with a substrate bias voltage of −75 V, Ar rate of 6 sccm and oxygen fraction of 25%. [ABSTRACT FROM AUTHOR]

In order to study the influence of the substrate bias on the properties of ZrN thin films deposited by radio-frequency magnetron sputtering for biomedical application. Films of ZrN were grown onto 316L stainless steel substrate using radio-frequency (rf) magnetron sputtering from a pure zirconium target in Ar - N2 gas mixture. The substrate bias voltage was varied from 0 to −100 V, which produces a variation in the structural and electrochemical properties of the obtained films. The deposited films were characterized by X-Rays Diffraction, Atomic Force Microscopy, scanning force microscopy and potentiodynamic polarization. [ABSTRACT FROM AUTHOR]

TiO 2 thin films are of paramount importance due to their pervasive applications. In contrast to previous published works where the substrate was heated at high temperatures to obtain TiO 2 crystalline phase, we show in this study that it is possible to deposit crystalline TiO 2 thin films on biased and unbiased substrate at room temperature using reactive rf magnetron sputtering. The bias voltage was varied from 0 V to −100 V. The deposited films were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy, Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and atomic force microscopy (AFM). The average crystallite size was estimated using x-ray diffraction. The results showed that the application of negative bias affects the surface roughness of the films and favors the formation of the rutile phase. The root mean square roughness (R rms ), the average grain size and the optical band gap of the films decreased as the substrate bias voltage was varied from 0 to −100 V. The UV–visible transmittance spectra showed that the films were transparent in the visible range and absorb strongly in the UV range. This study shows that biasing the substrate could be a promising and effective alternative to deposit TiO 2 crystallized thin films of engineered properties at room temperature. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the influence of plasma deposition parameters (the pressure and the substrate bias voltage Vs) on structure, surface morphology, hardness and electrochemical behavior (studied by potentiodynamic polarization and optical microscope (OM) in aggressive environment NaCl 3.5 wt%) of TiAlN coatings. The coatings were deposited by reactive RF magnetron sputtering (13.56 MHz). They were carried out during 60 min and their thickness was approximately 1 μm. Structural analysis shown that TiAlN coating crystallized in cubic (fcc) and hexagonal (hcp) structure with orientations in (1 0 0), (1 1 1), (2 0 0), (1 1 0), (2 2 0) and (3 1 1) planes. The deposited coatings present maximum hardness ( H = 25.75 GPa) and Young's modulus ( E = 479.82 GPa) at low pressure (20 mTorr) and −60 V of negative substrate bias. Also, mechanical properties ( H & E ) were strongly influenced by coatings density and grain size. Electrochemical tests revealed that XC48 steel substrate covered with TiAlN coating exhibits excellent corrosion resistance. [ABSTRACT FROM AUTHOR]

In this study we present the effect of negative bias applied to substrate and the pressure on the properties of TiC films (i.e. structure, Raman spectroscopy, electrical resistivity and hardness). The elaboration of our films has been carried out by RF-Magnetron Sputtering, 13.56 MHz, using two targets: titanium carbide and pure titanium. The film depositions have been done on silicon, glass and steel substrates. The total pressure was 10-60 mTorr. The attention was given to study the influence of different parameters, pressure and substrate-bias, on the properties of TiC layers. In this paper, a comparison between the properties of TiC prepared using pure titanium target and titanium carbide target is made. The deposited layers were characterized by XRD analysis, nanoindentation, four probe technique and Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Ti-Cr-N coatings were deposited on Si (100) and AISI D2 tool steel substrates by reactive DC magnetron co-sputtering technique from titanium and chromium target in mixed Ar/N 2 atmosphere. The Ar/N 2 ratio effects on the chemical composition, structure, morphology, intrinsic stress and mechanical properties of the Ti-Cr-N coatings were investigated. The growing process of Ti-Cr-N coatings can be divided into three stages: Stage I, in poisoning mode (low flow ratio 1 < Ar/N 2 ≤ 1.4), Stage II, in transition mode (intermediate flow ratio 1.4 ≤ Ar/N 2 ≤ 3) and Stage III in metallic mode (Ar/N 2 > 3). For all samples, XRD analysis shown the formation of mixed nitrides phases. In stage I, Ti 2 N, TiN 0.3 , and hexagonal-Cr 2 N phases were observed. In Stage II, TiN 0.3 , Cr 2 N, and cubic-TiN phases were formed, while only TiN and Cr 2 N are observed in stage III. The coatings deposited with Ar/N₂ ratio of 3 shows the largest hardness of 24 GPa which is attribute to the dense structure and smoother surface morphology. The properties of the films are discussed in terms of evolution growth stages resulting by the variation of Ar/N 2 flow ratios. [Display omitted] • The properties of TiCrN films evolve through three distinct stages as a function of the Ar/N 2 ratio. • For all stages, the structure of the films is a mixture of Ti-N and Cr-N binary nitrides. • The morphology evolution through the three stages was studied. • The residual stresses state results from the competition between tensile and compressive stress mechanisms. • The best mechanical properties are due to the densification structure and grain boundary strengthening mechanisms. [ABSTRACT FROM AUTHOR]

• ZrO 2 films were deposited on stainless steel 316L by RF magnetron sputtering. • The ZrO 2 coated 316L are hydrophobic. • Bioactivity tests in vitro demonstrate the formation of a hydroxyapatite layer on the films surface. The zirconia (ZrO 2) films were deposited using radio-frequency magnetron sputtering (RFMS) from a pure zirconium target in Ar-O 2 gas mixture with different percentage of the oxygen. The effect of Oxygen percentage on the film's characteristics was investigated by Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and tribology test. Also, the contact angle of the films was measured in order to evaluate their hydrophobicity. Additionally, in vitro test in artificial blood plasma and further SEM observations were performed to study bioactivity of the films. The experimental results showed that the roughness, the porosity and the thickness of the films depend on the oxygen percentage. According to XRD and Raman spectroscopy results, the films present a polymorph phase of monoclinic and tetragonal. Zirconia films at low oxygen percentage showed better hydrophobic behavior with 114.5° at 15% of oxygen. These films also exhibit a lower friction coefficient and wear rate (0.22 and 6 × 10−07 mm3/m respectively). However the best bioactive behavior was exhibited by the films deposited at 25% of oxygen due to their higher roughness and porosity. In fact, it was found that the bioactivity of the films is highly dependent on the porosity and roughness of the films. [ABSTRACT FROM AUTHOR]

Zirconium oxide (ZrO 2) thin films were grown onto 316L stainless steel by radio frequency magnetron sputtering (RFMS), at different substrate D.C. bias voltages (from 0 to −100 V). The deposition was performed using a pure zirconium target in the presence of an Ar-O 2 gas mixture. The characterization of the deposited films was performed using scanning Electron Microscope, atomic Force Microscopy, X-rays diffraction, Raman spectroscopy, nanoindentation and potentiodynamic polarization. The structures of all ZrO 2 films are crystalline. The monoclinic phase is predominant in the grounded films (0 V). However, the application of bias voltage depicts a tetragonal phase. Nanoindentation results reveal promoted values of the hardness of the ZrO 2 films. Corrosion behavior of the films was studied in Hank's solution using the potentiodynamic polarization method. The comparison between the uncoated samples and the coated ones showed a reduction in corrosion current density for coated samples. The minimum corrosion rate of the film deposited at −100 V was 0.04992 mpy, which is about 18 times less than that of the uncoated steel (0.88135 mpy). The optimum anti-corrosion performance and hardness were obtained for ZrO 2 deposited at a bias voltage of −100 V. • ZrO 2 films were deposited by magnetron sputtering from a metallic Zr target using oxygen as reactive gas. • ZrO 2 films with high hardness and high protective efficiency (94%) are demonstrated. • The hardness increases with the bias voltage applied to substrate. • Corrosion resistance is affected by negative bias voltage of ZrO 2 film. [ABSTRACT FROM AUTHOR]

In this work, TiO2 layers are synthetized on Ti6Al4V alloy substrate by electrochemical anodizing process in fluoride‐containing alkaline electrolytes and under different applied voltages (10, 20, and 30 V). The scanning electron microscopy (SEM) reveals a nearly regular and vertical alignment of TiO2 nanotubes (≈80–100 nm) for specimen treated at 20 V and an agglomerate of particles with no particular orientations for those specimens treated at 10 and 30 V. The X‐ray diffraction (XRD) indicates the formation of mixed phases of anatase and rutile. Wettability measurements exhibit hydrophilic and superhydrophilic surfaces, according to the anodization parameters. The electrochemical impedance spectroscopy (EIS), performed in a simulated body fluid (Hank's solution), reveals an increase in corrosion resistance for a bias potential of 20 V (262 kΩ) owing to the evolution in TiO2‐layer thickness, and then decreases for higher anodizing potential values due to the chemical dissolution of the obtained layer. TiO2 nanostructured layers for biomedical application are synthesized on Ti6Al4V substrate by electrochemical anodizing process in fluoride‐containing alkaline electrolyte under different applied voltages. The effects of anodizing parameters on the morphology, crystal phases, and the surface wettability are investigated. The electrochemical test in a simulated body fluid (Hank's solution) indicates the best corrosion resistance for specimen anodized at 20 V. [ABSTRACT FROM AUTHOR]

Titanium oxide (TiO2) films have been synthesized on quartz, silicon and textured silicon substrates by chemical ultrasonic spray deposition. The textured silicon substrate was carried out using Na2CO3 solution. The sample surface exhibits uniform pyramids with an average height of 5 µm. In this paper, particular attention is given to the TiO2 films prepared by spray ultrasonic system using Tetra iso-Propoxide Orthotitanate Titanium (TPOT) as a precursor. The solutions were sprayed onto substrates heated at various temperatures 350 - 550 °C. The properties of films as a function of temperature parameter were investigated using structural and optical analysis. According to XRD, FTIR and Micro-Raman spectroscopies, the anatase phase was found and exhibits nanograins of 9 to 15 nm in size. The indirect and direct bad gap were found to increase by increasing substrate temperature due to the decreasing of nanograins size and were estimated to be around 3.28 and 3.38 eV. A transmittance higher than 80% was found. This paper reports on anti-reflection coating application of TiO2 layers due to its good transparency and appropriate refractive index varies between 2.19 - 2.40 at λ = 632.8 nm as a function of temperature determined by UVVisNIR spectrophotometer and Ellipsometry. To achieve optimum anti-reflection characteristics different anti-reflection designs were experimentally examined with polished and textured substrates. The average reflectance of the polished silicon used in this study is 39%, with TiO2 it decreases to 9%. The textured surface reduces the average reflectance of silicon to be around 14% and it decreases dramatically to 5% after deposition of a single layer of TiO2 as an anti-reflection coating. The gain in density of the short-circuit photocurrent assigned to the reduction of reflection losses up to 44% and 58% were predicted with TiO2 single-coating in polished and textured silicon substrates respectively. [ABSTRACT FROM AUTHOR]

The control of the optical properties of ZnO nanostructured thin films by using different dopant elements paves the way for the development of potential materials for photonic and optoelectronic applications. In this work manganese (Mn) doped ZnO thin films were fabricated by rapid thermal evaporation method on a glass substrate having the same Mn content level of ~10% and annealed at different temperatures. XRD analysis showed that the annealed layers have hexagonal wurtzite structure, however, the unannealed layers showed only Zn peaks without any preferential direction. The elemental analysis of the films has been investigated by XPS, which revealed the presence of Mn and oxygen atoms for all layers. In addition, it was observed by FIB-SEM that the morphology of thin films changed with the annealing temperature. For an anneal at 500 °C nanoneedles appeared. Raman spectroscopy showed E 1 (TO) mode in the sample annealed at 500 °C which was attributed with the formation of nanoneedles structures. The optical transmission of the annealed films was in the range of 75–77% and the optical bandgap varied from 3.97 to 3.72 eV. These variations are related to the structural and morphological changes of the thin films with annealing temperature. • The effect of thermal annealing on the physical properties of nanostructured Mn doped ZnO thin films was investigated. • XRD analysis revealed that MZO layers after annealing crystallize in hexagonal wurtzite phase. • The morphology of MZO films changed with the annealing temperature. For an anneal at 500 °C nanoneedles appeared. • Raman measurements have also shown an additional mode E 1 (TO) at 467 cm−1 associated with the apparition of nanoneedles. • The optical constants n, α and the thickness d were successfully identified and determined only from the transmittance spectra using the PSO algorithm. [ABSTRACT FROM AUTHOR]