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Mechanical robustness, biocompatibility, and antibacterial performances are key features for materials suitable to be used in tissue engineering applications. In this work, we investigated the link existing between structural and functional properties of TiCu(Ag) thin films deposited by physical vapor deposition magnetron sputtering on Si substrates. The thin films were characterized by X-ray diffraction (XRD), nanoindentation, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The TiCu(Ag) thin films showed complete amorphous structure and improved mechanical properties in comparison with pure Ti films. However, for contents in excess of 20% Ag, we observed the appearance of nanometric Ag crystallite. The TiCu(Ag) thin films displayed excellent biocompatibility properties, allowing adhesion and proliferation of the human fibroblasts MRC-5 cell line. Moreover, all the investigated TiCu(Ag) alloy display bactericidal properties, preventing the growth of both Pseudomonas aeruginosa and Staphylococcus aureus. Results obtained from biological tests have been correlated to the surface structure and microstructure of films. The excellent biocompatibility and bactericidal properties of these multifunctional thin films opens to their use in tissue engineering applications.

NiO thin films with different annealing temperature and films thickness were fabricated by magnetron sputtering on the Pt/TiOx/SiO2/Si substrates. The XRD results show the crystallinity of films can be improved with the annealing temperature and films thickness increased. While the preferential orientation is affected by annealing temperature and films thickness. The SEM results show that the average size of the needle like grains shape increases gradually from 42.4 nm to 72.5 nm and the grains of films are seen to be more uniform, with a smoother and finer morphology with film thickness increasing. XPS measurements show that two valence states of Ni2+ and Ni3+ exist in NiO films with the Ni2+/ Ni3+ ratio 1.01. However, the Ni3+ refers to the structure that contains Ni2+ ions with holes and not to Ni2O3 phase as observed from the XRD results and the O1s XPS spectra, making the grains conductive due to plenty of holes. It results the grains have a key contribution to dielectric behavior. The frequency domain spectroscopy shows the films thickness and annealing temperature have a significance influence on the dielectric constant and dielectric loss tangent. And the preferential orientation of NiO films play a non-negligible impact on the dielectric performance due to the polarized NiO (111) plane.

In this study we investigate the ability of RF magnetron sputtered nylon 6,6 films (C:H:N:O) to store and release two model antibiotics, ampicillin and ciprofloxacin, that differ significantly in their chemical structure. We demonstrate that the addition of nitrogen to the deposition process leads to a substantial enhancement in the abundance of nitrogen-containing functional groups in the resulting coatings as well as to the significant changes in their swelling and dissolution. These variations were found to result in different impregnation and release capabilities of the produced coatings: an almost 5 times higher amount of released antibiotics was observed for the samples prepared in nitrogen-rich atmosphere when compared to films deposited in pure argon. It was also found that the amount of released antibiotics strongly depends on the natural character of the antibiotics used. However, it is demonstrated that minimum inhibitory concentrations against S. epidermidis and E. coli can be exceeded for both antibiotics.

CrMoCN coatings with various Mo contents were prepared on Ti6Al4V disks and Si wafers using unbalanced magnetron sputtering at various Mo target currents, and their crystallite phases and bonding structures were characterized using XRD and TEM as well as XPS, respectively. The mechanical properties of coatings were measured by nano-indenter and the tribological properties of CrMoCN/SiC tribopairs in artificial seawater were tested by ball-to-disk tribo-tester. The results showed that Cr, Mo and N elements mainly existed in the form of (Cr, Mo)N solid solution crystals, while C element mainly existed as amorphous a-C and amorphous a-CNx. The hardness and elastic modulus of CrMoCN coatings increased first, and then decreased as Mo target current further increased to 3.0 A. The friction coefficients and wear rates of CrMoCN/SiC tribopairs decreased overall with the increase in the Mo target current due to the synergistic lubrication and wear-reducing effect of tribolayers (MoO3 and SiO2·2H2O). The abrasive and tribo-chemical wear were the wear mechanisms of CrMoCN/SiC tribopairs. CrMoCN-3.0 coating showed the best tribological properties in the artificial seawater.

Two antimony (Sb)-doped tin oxide (ATO) targets of different densities were used to illustrate the chemical evolution of target surfaces during RF magnetron sputtering. The phase compositions, the microstructures, the chemical states, and the electrical and optical properties of the deposited ATO films were revealed. The ATO film deposited by the high-density (98%) target yielded an enhanced electrical conductivity of 3.21 × 10−2 Ω·cm (under a low power density of 100 W without substrate heating) and excellent optical properties with an average transmittance of 94.65%. For the target with pores and dielectric inclusions, the decrease in Sb content and the variation in the chemical state of tin (Sn) degraded the electrical conductivity and the optical properties of the deposited ATO films. The chemical state of the low-density ATO target varied significantly due to micro-arcing caused by warps in the electrical field during sputtering.

Tm3+ doped SnO2 semiconductor thin films were prepared by RF magnetron sputtering method. The doping effects of rare-earth thulium on the crystal structures, optical properties, chemical compositions, surface morphologies of tin-oxide thin films, together with the electrical properties of the corresponding SnTmO thin film transistors (TFTs), were investigated. SnTmO semiconductor thin films with polycrystalline structures feature a wide bandgap of over 3.8 eV. XPS results reveal the typical photoelectron signals of Sn4+ and Tm3+. Smaller crystallite size and more grain boundaries can be formed in doped SnO2 samples which may be responsible for the degradation of device mobility. It was found that the electrical properties of SnO2 TFTs can be modulated by Tm3+ incorporation. The appropriate Tm3+ doping concentration is around 1.6 at.% within our experimental conditions. The optimized field-effect mobility, subthreshold swing, threshold voltage, on-off current ratio and the interface trap density are 5.5 cm2 V−1 s−1, 0.618 Vdec−1, −2.3 V, 5 × 107 and 6.7 × 1011 cm−2, respectively. Stability measurements show threshold voltage shifts of 12.3 V and −11.7 V in PBS and NBS process respectively. This study may provide useful understandings on rare-earth doped SnO2 semiconductors.

Van der Waals (vdW) layered GeTe-Sb 2 Te 3 superlattices (GST-SL) have attracted enormous attentions due to the ultralow power consumption for nonvolatile phase change memory. In this paper, effects of biaxial strain on interfacial intermixing and local structures in strain engineered GST-SL were studied. Highly (0 0 l ) textured GST-SL with thickness-varied Sb 2 Te 3 sublayers were fabricated by magnetron sputtering and investigated with multiple analyses on surfaces and interfaces. The appearance of Ge-Sb-Te alloys indicated the interfacial Ge/Sb intermixing in strain engineered GST-SL, which actually were composed of Sb 2 Te 3 quintuple layers, Ge-Sb-Te vdW layers and isolated GeTe bilayers. Grazing incidence x-ray diffraction (GID) and x-ray photoelectron spectroscopy (XPS) results revealed that biaxial strain not only facilitated the interfacial intermixing, but also caused the reconfiguration of Ge-Sb-Te vdW layers. Raman spectra indicated that vertical and in-plane vibrations of GeTe layers were not affected by the interfacial intermixing and the newly-formed Ge-Sb-Te layers had similar vibration characteristics as that of GeTe layers. A modified switching mechanism of GST-SL, relating to both the amorphous-crystalline phase transition of GeTe and Ge-Sb-Te layers incorporated into the Sb 2 Te 3 matrix, was then presented. The present studies shed new light on strain engineering for GST-SL and indicate their potential optoelectronic applications.

Copper oxide thin films are grown by reactive magnetron sputter deposition. To define the parameter space to obtain CuO films, the influence of the oxygen partial pressure, the total pressure, and the discharge current was investigated on the phase formation. A clear change from pure copper, over cuprite (Cu 2 O), and paramelaconite (Cu 4 O 3 ) to tenorite (CuO) thin films with increasing oxygen partial pressure was observed using X-ray diffraction and Fourier transform infrared spectroscopy. The main driving force defining the phase composition is the oxygen partial pressure, while the influence of the total pressure, and the discharge current is minimal. A clear condition to obtain phase pure CuO films could be defined based on the measured discharge voltage. Both the domain size, and the Bragg peak position for pure CuO thin films can be correlated to the negative ion bombardment during film growth.

Multilayer thin films have the potential to act as high dielectric strength insulation for wire and microelectronics. In this study, films consisting of 2, 4 or 8 layers, composed of Al2O3 with SiO2 or Ta2O5, were prepared via pulsed direct current and radio frequency magnetron sputtering to a thickness of between 152 and 236 nm. The dielectric strengths of all films exceeded the 310 Vμm−1 achieved for PDC Al2O3. Maximum dielectric strengths were obtained for four layer composites; Al2O3-SiO2-Al2O3-SiO2 (466 Vμm−1) and Al2O3-Ta2O5-Al2O3-Ta2O5 (513 Vμm−1), each containing two PDC-Al2O3 and two RF-SiO2/Ta2O5 layers. Whilst the average dielectric strength was higher in the Ta2O5 composites, they suffered from higher leakage prior to breakdown with ca. 6.5 nA compared to ca. 0.1 nA for SiO2 composites. The mechanical properties of the composites were poorer due to increased intrinsic coating stress. Samples exhibited complete interfacial delamination with maximum coating adhesion strengths of 22 and 25 MPa. The variance resulted from larger coefficient of thermal expansion for Ta2O5 compared to SiO2. Sputtered composites of Al2O3 and either SiO2 or Ta2O5 had high breakdown strength with reasonable adhesion and could be suitable for insulating copper conductors in the aerospace and automotive industries.

Transparent conducting In and Mg codoped ZnO (IMZO) thin films were deposited on quartz substrates at room temperature by radio frequency magnetron sputtering. The influence of Mg concentration (from 0 to 6 at.%) on the structural, optical and electrical properties of IMZO thin films was investigated in detail. All IMZO thin films have typical hexagonal wurtzite structure with a preferential orientation along the c-axis and show high average optical transmittance above 85% in the visible region. And, the optical band gap is tunable with the addition of the Mg dopants. The presence of indium favors energetically the formation of abundant zinc interstitial (Zni) related shallow donor defects, thus greatly increasing the carrier concentration in the film. However, it was found that the electrical conductivity decreased as the Mg content increased. The main origin is related to the density reduction of Zni-related defects. Furthermore, the electrical properties of IMZO thin films can be significantly improved by thermal diffusion of extrinsic Zn atoms which creates extra Zni-related defects that provide electron carriers. These efforts will facilitate the development of ZnO-based TCO thin films.

The amorphous tantalum oxynitride (TaO x N y ) thin films were prepared on silicon (100) substrates by magnetron sputtering system with different techniques of conventional reactive sputtering and reactive gas-timing (RGT). The films were studied via spectroscopic ellipsometry (SE) measured in the range of 0.75–5.0 eV with 0.025 eV interval at 70° incident angle, and the optical model based on Tauc-Lorentz function was constructed to extract the properties of the films. The SE results indicated that all prepared films were grown homogeneously and show different optical properties upon their deposition conditions and techniques. The optical properties of film prepared by conventional reactive sputtering were close to the tantalum oxide film (TaO). The refractive index and optical band gap (E g ) of RGT samples changed with the oxygen timing and correlated with the change of oxygen and nitrogen concentration of the films. In addition, the morphologies, crystallinities, atomic concentrations and distributions of nitrogen atoms in the films analyzed by field-emission scanning electron microscopy, glazing-incident X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy are also discussed.

The Design of Experiments is a promising method to investigate the cause-effect relation between the mid-frequency magnetron sputtering parameters on the structural and mechanical properties of amorphous carbon (a-C) films. Based on the Central Composite Design, the cathode power of two graphite targets, bias voltage, and mid-frequency were simultaneously varied from 1500 to 4000 W, −100 to −200 V, and 20 to 50 kHz, respectively. The chemical bonding state was characterized using UV and visible Raman spectroscopy with excitation wavelengths of 266 and 532 nm. Corresponding measurements were performed by X-ray photoelectron spectroscopy (XPS) using synchrotron radiation. Additionally, hardness and elastic modulus of the sputtered a-C films were determined in nanoindentation tests. Multi-wavelength Raman spectroscopy identified an sp3 content below 20%, with most a-C films having an sp3 value in the range of 12 to 18%. The formation of sp3 bonded atoms is negatively influenced by a high cathode power and bias voltage, whereas the highest sp3 content is obtained with a-C films sputtered with a cathode power and bias voltage of 2750 W and −150 V. However, higher values of the cathode power and bias voltage result in a film delamination and decrease of the sp3 concentration. The bonding state affects the mechanical properties, as high hardness and elastic modulus result from a high sp3 content. Therefore, a targeted adjustment of cathode power and bias voltage is necessary to obtain a-C films with a high hardness. In contrast, the mid-frequency does not have a significant impact on the mechanical properties. In conclusion, the Central Composite Design has proven to be a suitable method to investigate the cause-effects of the sputtering parameters on the properties of the a-C film.

Achievements of higher efficiency, excellent reliability, and lower cost in concentrating solar power plants are impeded by the operating temperature and thermal stability of solar selective coatings (SSCs) on solar collectors. Improving the air-stability of SSCs in mid-temperature is of great significance. We developed a multilayer SSC composed of Si3N4, a-Si, Ag, and Cr2O3 by magnetron sputtering. The amorphous silicon (a-Si) is served as the solar absorbing material. Optical constants of the a-Si thin films deposited at different sputtering powers and working pressures were measured by a spectroscopic ellipsometer after confirming their amorphous nature by XRD. Theoretical solar absorptance of the SSC is 88.38% after optimizing the thickness of the a-Si layer. It was noted from cross-sectional morphologies characterized by FESEM that the SSC exhibited a total thickness of 2 μm, and no obvious interfacial diffusion was observed after annealing at 400 °C in air. In addition, the experimental reflectance spectra revealed an improved solar absorptance of 78.08% and a decreased thermal emittance of 1.68% after heat treatment in air at 400 °C for 10 h. All these results show that the proposed SSC exhibits good solar selectivity in air and is a promising candidate for intermediate solar thermal applications.

Titanium alloys are widely used in industrial fields because of their superior characteristics, but they also have disadvantages leading to fretting fatigue (FF) damage. The silver-based composite films were deposited on a Ti6Al4V alloy substrate using ion-assisted magnetron sputtering for improving the fretting fatigue (FF) resistance of a Ti6Al4V alloy. The surface morphology was characterized by atomic force microscopy (AFM), and micro-structure was characterized by X-ray photoelectron spectroscopy measurements (XPS), X-ray diffractometry (XRD), and transmission electron microscopy (TEM), respectively. The bonding strength and toughness of films were analyzed using a repeated press–press test system that was manufactured in-house. The FF resistance of titanium alloy with the silver-based composite films was investigated using home-made FF devices. The results showed that the FF resistance of the titanium alloy was improved by the Ag-TiN composite films, which were fabricated with an Ag solid lubricating film doped with a hard TiN phase (60–80 at.% Ag). This is attributed to the fact that the composite films had better comprehensive strength-toughness behavior, friction lubrication property, and high bonding strength. However, when the atomic fraction of Ag in the composite film was larger than 90%, it became difficult to form the TiN phase, and it failed to improve the comprehensive strength-toughness behavior of the composite film.

International audience; The structure, the chemistry, and the magnetic properties of MnCoGe thin films elaborated by reactive diffusion were investigated. In situ X-ray diffraction (XRD) was used to study phase formation during thin film reaction. MnCo, MnGe, and CoGe binary systems were studied before investigating phase formation during Mn-Ge-Co ternary system reaction. Three pure layers of Mn, Ge, and Co were successively deposited by magnetron sputtering on SiO2 to form a 200 nm-thick Co/Ge/Mn stack, and annealed. Six phases were observed during reaction, first following the sequential phase formation observed for the binary systems at the two Mn/Ge and Ge/Co interfaces, and ending with the formation of a single ternary compound MnCoGe at 673 K. The structure and the composition of the MnCoGe films were characterized using XRD, atomic force microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The magnetic properties of the films were studied using superconducting quantum interference device (SQUID) and ferromagnetic resonance (FMR) measurements. The obtained MnCoGe thin films are polycrystalline with the stoichiometric composition Mn:Co:Ge(1/3:1/3:1/3), and show high porosity. They are made of grains exhibiting both the Ni2In-type hexagonal structure and the TiNiSi-type orthorhombic structure.

It is generally accepted that the crack is appeared when the thermal stress is accumulated which caused by the mismatch of coefficient of thermal expansion, through which oxygen will severely destroy the substrate at high temperature environments. Therefore, the coatings with gradient structure to reduce thermal expansion mismatch should greatly improve their service stability. Here Al Y gradient coating is prepared on γ-TiAl alloy by magnetron sputtering. The results show that the hot corrosion resistance of γ-TiAl alloy could be greatly improved, and the activation energy at (750 °C–950 °C) can be calculated to be 126.88 KJ/mol for the coating. The Al2O3 and Y3Al5O12 (YAG) are the primary phases after hot corrosion, thus providing efficient protection at 750, 850 °C. At 950 °C, the consumption of oxide layers is accelerated due to the increased temperature so that some corrosive elements (such as S and Na) unavoidably invade into the scale. The improvement of hot corrosion resistance primarily owes to the existence of Y preferentially oxidizes Al to form α-Al2O3, and the effect of grain refinement of YAG phases.

Ag Zr alloy films were deposited on flexible polyimide (PI) substrates by magnetron sputtering and subsequently subjected to vacuum annealing. Effects of annealing temperature, Zr content and film thickness on formation of Ag particle and the surface enhanced Raman scattering property of Ag particles/Ag Zr alloy films have been investigated. Results show that microstructure of Ag Zr alloy film changes significantly after annealing and a large number of regular polyhedral Ag particles spontaneously formed on the surface of annealed Ag Zr alloy films. The Ag particles are single crystal and uniformly distributed on the Ag Zr alloy films surface to form the Ag particles/Ag Zr alloy films composite structure with large specific surface area. The detection limit of R6G concentration using Ag particles/Ag Zr alloy films covered by 12 nm Ag film as SERS substrate is significantly lower than 5 × 10−8 M (1 M = 1 mol/L) due to its abundant active “hot spots”. The particle/film composite structure obtained in this paper provides a method to prepare the highly efficient SERS substrates.

Nanocrystalline TiO2 thin films were deposited on borosilicate glass substrates using pulsed DC reactive magnetron sputtering in oxygen rich O2 Ar gas mixtures. The influence of sputtering power and argon‑oxygen gas flow ratio over crystallinity, crystal texture and surface morphology of the films was investigated. Interestingly, there was no correlation between the O/Ti concentration ratio in the films and their indirect band gap values. Based on experimentally observed band gap values and other properties of the films the model of the films consisting of nearly stoichiometric TiO2 crystals with a small fraction of weakly coordinated Ti impurities or amorphous low oxidation state titanium suboxide formations is proposed. Photocatalytic activity of the deposited films was analysed using inorganic markers and strong correlation between photocatalytic efficiency of TiO2 films with the (004) Crystalographic Preffered Orientation parameter was observed.

Titanium nitride (TiN) films can be utilized as hard and protective coatings for synchronizer ring, which is the key components of the car gearbox. The tribological properties of synchronizer ring play a key role in the safety and reliability of the car shifting system. The aim of the present work is to improve tribological properties of synchronizer ring and investigate effects of depositing gas on preferred orientation, surface morphology, surface roughness and tribological properties of TiN thin films. The as-prepared films are deposited on copper alloy (TL084) and Si (100) substrates by a closed field unbalanced magnetron sputtering system. The different sputtering gas with the volume ratio of argon to nitrogen of 1:3, 1:2 and 1:1 is employed. Results indicated that the increasing argon concentration in the gas mixture promotes the growth of TiN nanocrystallines and reduces its surface roughness, friction coefficient and wear rate. TiN films have the (200) preferred orientation at low argon concentration, while the (111) preferred orientation dominates at high argon concentration. TiN thin films deposited with the ratio of argon to nitrogen of 1:1 has the best tribological properties, which are the best sputtering condition as an ideal functional coating for synchronizer ring.

Titanium nitride as a very representative ceramic film has been widely applied in cutting tools. Improvement the toughness and friction property of titanium nitride based films have been a research hotspot. In this paper, ruthenium was added into the titanium nitride brittle matrix and titanium ruthenium nitride composite hard films were synthesized using RF magnetron sputtering system and its crystal structure and room temperature tribological properties were investigated. The results showed that the addition of ruthenium above 1.3 at.% into the face-centered cubic (fcc) titanium nitride matrix exceeded the solid solubility limit and induced other phase of hexagonal close-packed (hcp) ruthenium. Addition of ruthenium into the titanium nitride matrix could enhance the fracture toughness, since it induced much more dislocations and interfaces. Compared with titanium nitride film, the content of adding ruthenium above 0.9 at.% reduced friction coefficient significantly without sacrificing the wear rate.

Zinc oxysulfide (Zn(O,S)) is widely used for photovoltaic and optoelectronic devices because its electronic properties are tunable with adjustments to the S-to-O composition ratio. Zn(O,S) thin films used in devices are typically assumed to have constant S-to-O composition ratios across their thicknesses. However, S-to-O composition ratio gradients, and thus electronic property variations along the vertical direction, can be naturally induced. Such gradients can enhance device performance. In this work, we analyzed the S-to-O composition ratios along the thickness directions of Zn(O,S) thin films deposited at a fixed O2 gas flux. Natural O enrichment was observed near the bottom of the film, attributed to the highly reactive nature of the sputtering process. By increasing O2 gas flux during sputtering, more compositionally uniform thin films were obtained. We suggest that non-uniform phase distribution in the depth direction could be considered for achieving desired composition ratios when depositing Zn(O,S) thin films using reactive sputtering.

This work deals with the properties of secondary particles, i.e., sputtered target and scattered primary particles, for the ion beam sputtering of TiO2 in a reactive oxygen atmosphere. The angular and energy distributions in dependence on ion beam parameters (ion energy, ion species, or ion mass) and geometrical parameters (ion incidence angle, polar emission angle, or scattering angle) were investigated. The angular distributions of sputtered Ti particles were determined by the collection method, i.e., by growing TiO2 thin films and measuring the thickness, composition, and mass density. The distributions can be described by the superposition of an isotropic and an anisotropic part. The anisotropic part relative to the isotropic part gets more pronounced with decreasing ion energy, increasing ion incidence angle or changing the process gas from Ar to Xe. An energy-selective mass spectrometer was used to measure mass and energy distributions of secondary ions. The most prevalent species were identified to be O+, O2+, Ti+, TiO+, Ar+, and Xe+ ions. The energy distributions of Ti+ and TiO+ ions show a low-energy maximum between 10 eV and 30 eV, followed by an exponential decay. When decreasing the scattering angle, the high-energy tail extends to higher energies. O+, O2+, Ar+, and Xe+ ions show a low-energy maximum between 5 eV and 20 eV, which is followed by a sudden signal drop for scattering angles larger than 90°. For scattering angles smaller than 90°, additional peak(s) at higher energy appear, which are assigned to direct scattering and/or direct sputtering events. The experimental results are compared to calculations based on elastic collision theory and to simulations done with the Monte Carlo code SDTrimSP. The results are also discussed in relation to secondary particle properties for the reactive ion beam sputtering of Ti and to properties of TiO2 thin films grown by reactive ion beam sputter deposition with the same setup and the same parameters. Among others, it was found that sputtering of the TiO2 target exhibits less anisotropy contributions than sputtering of the Ti target.

The aim of this study was to provide important insights into the micromorphology of sputtered indium tin oxide (ITO) prepared on glass substrates by direct current (DC) magnetron sputtering at room temperature using atomic force microscopy (AFM) and multifractal analysis. The samples were annealed at 450 °C in air and were divided into five groups to discuss the results, in correlation with the ambient combinations applied, as follows: I group, using argon (Ar); II group, using argon with oxygen (Ar + O2); III group, using argon with oxygen and nitrogen (Ar + O2 + N2); IV group, using argon with oxygen and hydrogen (Ar + O2 + H2); and V group, using argon with oxygen, nitrogen and hydrogen (Ar + O2 + N2 + H2). The VI group was the reference group. AFM was used to image the surface micromorphology in tapping mode, on square areas of 2 μm × 2 μm. The ITO thin film surfaces are characterized by 3-D (three-dimensional) nanometer-scale patterns highlighted by multifractal features which reflect the process used during the fabrication of thin films. In addition, the AFM images were stereometrically analyzed, in accordance with ISO 25178-2: 2012 and ASME B46.1-2009. The results have shown that the multifractal approach in correlation with the stereometric surface analyses are efficient tools for quantifying the 3-D surface microtexture changes at different fabrication combinations.

Zr(1-x)Mo(x)N thin films were deposited by reactive magnetron sputtering with Mo content varying from 0 to 20 at.%. GAXRD revealed a gradual shrinkage of ZrN lattice constants as Mo concentration increased while no molybdenum crystalline phases were identified in ZrMoN coatings. XPS data showed a disturbance in ZrN electronic environment due to Mo presence, indicating a substitutional solid solution formation for samples up to 20 at.% Mo. Oxidation tests were carried out at 773 K, 873 K and 973 K for all thin films. ZrMoN samples did not maintain the original nitride structure when exposed to such high temperatures. On the other hand, Mo addition in ZrN matrix was favorable to the stabilization of the tetragonal zirconia (t-ZrO2) in preference to the more stable monoclinic zirconia (m-ZrO2) phase at high temperatures.

This article describes a facile fabrication of spinel structured n-type CuAl2O4 thin film with nano-grass like morphological feature by radio frequency (RF) magnetron sputtering technique and the direct realization of this structure as room temperature NH3 gas sensor. X-ray diffraction (XRD) study confirmed the predominant presence of cubic phase CuAl2O4 in the homemade sputtering target and also in the fabricated films. X-ray photoelectron spectroscopic (XPS) investigation confirms the formation of Al3+ and Cu2+ chemical states in the films. Purity and stoichiometry of the deposited films were further confirmed by energy dispersive X-ray spectroscopy (EDX). A randomly aligned nano-grass like morphology with diameters of 25–100 nm and lengths in the range of 0.5 to 2 μm was observed for the film deposited with 300 W sputtering power on quartz substrate by FESEM study, which provides more reaction sites for gas molecules due to their high aspect ratios (length/diameter). The gas sensing measurements revealed that the prepared n-type CuAl2O4 thin films exhibited superior sensing performance towards ammonia gas in terms of high sensor response, quick response time and recovery time, high sensitivity, long stability, and good reproducibility even at room temperature operation condition. Therefore, we believe that the prepared n-type CuAl2O4 thin films have potential for the detection of ammonia gas leaks in chemical industries.

Wear as a tribological process has a major influence on the reliability and life of journal bearings. The influences of Sn element doping on the microstructure and tribological properties of AlSn coatings on the surface of journal-bearing alloy were investigated by magnetron sputtering. AlSn coatings exhibit equiaxed crystals. Phase compositions transform from crystalline to amorphous as grain sizes gradually decreases with increased Sn target current. Sn mainly exists as a simple substance composed of Sn Sn bonds, reducing the friction coefficient of AlSn coatings sliding against a GCr15 steel ball. The hardness is 40 HV0.025, and the lowest friction coefficient of AlSn coatings was 0.15 when ISn is 0.25A. Overall, the AlSn coatings have excellent microstructure and tribological properties.

Carbon nanofibers (CNFs) functionalized by ferromagnetic metals possess many potential applications in the microwave absorption. In this study, CNFs were functionalized by FeCo coatings with a DC-magnetron-sputtering method. The phase composition, microstructure, magnetic properties and electromagnetic wave absorbability of the new composites (FeCo/CNFs) have been studied. The obtained results demonstrate intensity magnetism in FeCo/CNFs, where the maximum saturation magnetization reaches up to 3.23 emu/g, and the minimum coercivity is 161.27 Oe. For the sample with a thickness of 4 mm, two absorption peaks located in the range of 3.81–4.36 GHz and 14.03–16.35 GHz can be observed. While the optimized reflection loss value of −24.05 dB was found at 14.88 GHz. Compared with the pristine CNFs, FeCo/CNFs exhibit stronger absorption and wider absorption band, because of the introduced FeCo coatings as well as the destructive interference between FeCo and CNFs. The method developed in this study will pave a new way for the development of CNF-based electromagnetic-wave absorbing materials.

Progressive improvement in the TCO characteristics of ITO (In2O3:Sn) thin films grown at substrate temperature (TS ∼ 232 °C) near the melting point of Sn has been pursued via optimization of gas pressure in the RF magnetron sputtering system. The optical transmission characteristics virtually remain consistently impressive on varying the gas pressure; however, crystallinity improves with significant dominance along 〈222〉 crystallographic orientation at an optimum gas pressure of 10 mTorr. Simultaneously, enhanced doping of the In2O3 network by Sn4+ active dopants along with optimum reducing condition attained at 10 mTorr pressure in the magnetron plasma provide maxima of both concentration and mobility of the charge carriers in the ITO films prepared at each substrate temperature in the range 200–350 °C and lead to a very high TCO figure of merit characteristics. At lower gas pressure below 10 mTorr, although dopant incorporation increases, formation of enhanced number of electrically inactive dopants (Sn2+) (reduced Sn4+/Sn2+ ratio) deteriorates the electrical characteristics of the ITO films. On lowering of gas pressure beyond the optimum reducing condition in the plasma, changes in the nature of decay of the concentration and mobility of the charge carriers depend sensitively on the substrate temperature. The carrier concentration reduces rapidly at higher TS while carrier mobility diminishes significantly at lower TS. Accordingly, dopant concentration and the oxidation state of the In2O3:Sn matrix together control the carrier characteristics in a complex manner which is again sensitively influenced by the substrate temperature and the working gas pressure of the magnetron plasma. Significantly superior ohmic contact of the optimum ITO film with c-Si wafer evolves due to narrowing of the junction barrier height (φB) arising by virtue of increased carrier concentration in ITO, thanks to effective doping by Sn4+. Improved c-Si/ITO junction characteristics admit supplementary application feasibility of ITO films in devices fabrication, particularly as transparent electrodes in c-Si p-n junction solar cells.

Precise switchover of numerous resistance states is desirable to achieve repeatable multilevel data storage memory windows. However, this could be hindered by the inherent random nature of oxygen vacancy creation. In this study, oxygen-deficient CeO2−x thin films were fabricated on indium tin oxide (ITO)-coated/glass substrates using radio-frequency magnetron sputtering at room temperature to obtain simple Ni/CeO2−x/ITO/glass devices. Multilevel bipolar resistive switching characteristics were investigated by controlling the RESET voltage and current compliance. The device could be regarded as four-level switching memory, controlled by the RESET voltage. An increase in the RESET-stop voltage from −1.5 to −2.0 V increased the Schottky barrier height, leading to an improvement in the ON/OFF ratio. The multilevel resistive switching behavior could be attributed to the formation and partial rupture of conductive filaments owing to interfacial oxygen ion migration. This study shows the potentials of the Ni/CeO2−x/ITO/glass devices for multilevel data storage resistive random-access memory applications.