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In this study, we modified the surface of bioresorbable electrospun poly-( l -lactic) acid (PLLA) scaffolds by reactive magnetron sputtering of a titanium target under a nitrogen atmosphere. We examined the influence of the plasma treatment time on the structure and properties of electrospun PLLA scaffolds using SEM, XRF, FTIR, XRD, optical goniometry, and mechanical testing. It was observed that the coating formed did not change physicomechanical properties of electrospun PLLA scaffolds and simultaneously, increased their hydrophilicity. No adverse tissue reaction up to 3 months after subcutaneous implantation of the modified scaffolds was detected in in-vivo rat model. The rate of scaffold replacement by the recipient tissue in-vivo was observed to depend on the plasma treatment time. [ABSTRACT FROM AUTHOR]

• Substrate governs the structure of sputtered Co 3 O 4 films deposited at 620 K. • Flat and epitaxial (111) Co 3 O 4 film grows on α-Al 2 O 3. • Reciprocal space maps with synchrotron light show 0.1905% out-of-plane strain. • a-SiO 2 leads to flat, unstrained, polycrystalline film with (111) texture. • LaAlO 3 induces a rough and strained film with strong (100) and (110) texture. We report a systematic study of the substrate's influence on the structure of Co 3 O 4 thin films grown by direct current reactive magnetron sputtering. Three different substrates have been simultaneously loaded to the deposition chamber and held at 620 K during growth: amorphous fused silica (a-SiO 2), LaAlO 3 (001), and α-Al 2 O 3 (0001). Samples were characterized using atomic force microscopy, Raman spectroscopy, and high-resolution X-ray using synchrotron radiation (HR-XRD). Raman spectra showed bands corresponding to modes of Co 3 O 4. The θ-2θ (HR-XRD) scans confirmed only the presence of the cubic spinel Co 3 O 4 phase with its texture reliant on the sample substrate used. Rocking curves indicate that α-Al 2 O 3 favors (111) Co 3 O 4 film orientation (smaller mosaic spread). High-resolution 3-D Reciprocal Space Map analysis covering both (0006) α-Al 2 O 3 and the (222) Co 3 O 4 reflections have shown out-of-plane strain (0.1905%) and presented an in-plane isotropic intensity distribution of the film reciprocal lattice point, indicating no preferred mosaic direction. The substrate epitaxy governs the structure and morphology of the three samples, going from a rather flat, but polycrystalline textured Co 3 O 4 film on a-SiO 2 , to a flat highly oriented strained film on α-Al 2 O 3 and a rough highly textured and strained film on LaAlO 3. [ABSTRACT FROM AUTHOR]

Reactive High Power Impulse Magnetron Sputtering (HiPIMS) of TiO 2 thin films was carried out to investigate the influence of ion parameters and the deposition temperature on the film crystallinity and photocatalytic performance. In order to limit unintentional substrate heating, a deposition setup with long target-to-substrate distance was used. Different HiPIMS pulse configurations, deposition temperatures and substrate bias were evaluated. TiO 2 films prepared by pulsed dc magnetron sputtering were used as reference. Films deposited at room temperature were all found to be X-ray amorphous, and a minimum temperature of 200 °C was needed for film crystallization irrespective of the mode of operation. This is attributed to the relatively long target-to-substrate distance of 180 mm used in this work. The growth of a specific polymorph was shown to be dependent on the operation mode, where a high oxygen partial pressure was ideal for anatase formation. The photodegradation rates were, as expected, found to be highest for crystalline samples, where single- and mixed-phase films yielded similar rates. Furthermore, the photodegradation rates of HiPIMS films deposited without substrate heating could be enhanced up to 3 times as compared to the corresponding pulsed dc reference film. The ion assistance in HiPIMS is also beneficial at moderate temperatures, here 200 °C, where an improved crystallinity as compared to pdcMS, was observed. [Display omitted] • TiO 2 deposited by reactive HiPIMS and pdcMS with long target-to-substrate distance • The effect of substrate temperature, bias, and peak power density investigated • All films deposited without substrate heating were X-ray amorphous • Enhanced photocatalytic activity of HiPIMS films grown without heating confirmed [ABSTRACT FROM AUTHOR]

Scandium oxide films were deposited on fused silica substrates by reactive pulsed DC magnetron sputtering. The use of feed-back optical emission monitoring enabled high-rate reactive deposition of films with tunable stoichiometry and properties. The under-stoichiometric, stoichiometric and over-stoichiometric scandium oxide films were prepared. The compressive stress in films was between 235 and 530 MPa. We showed that phase structure, density, surface roughness and optical properties of the scandium oxide are affected by the film stoichiometry and deposition conditions. Transparent scandium oxide films were slightly hydrophobic (94 ± 3°), homogeneous with a crystallite size of 20 ± 5 nm. The lowest extinction coefficient 0.7 × 10 −3 , the highest refractive index 2.08 (both quantities at the wavelength of 355 nm) and the highest density 4.1 ± 0.1 g cm −3 exhibited film prepared with the stoichiometric composition. Stoichiometric scandium oxide can be used in various optical applications as high refractive index and wide bandgap material. Transitions to under- or over-stoichiometry lead to a decrease of film density, refractive index and increase of the extinction coefficient. [ABSTRACT FROM AUTHOR]

We deposit hydrogenated amorphous carbon (a-C:H) films by magnetron sputtering of graphite in an Ar + C 2 H 2 mixture at various bias voltages. The mechanical properties, Raman spectra, and high-vacuum frictional behaviors of the a-C:H films indicate that the films deposited at bias 0, –50, and −100 V are polymer-like carbon (PLC) films and the film deposited at −150 V is a diamond-like carbon (DLC) film. The lifetimes of superlubricity, with friction coefficient ∼0.002, of the PLC films in high-vacuum increase from 10000 to 28000 cycles with increasing bias, although the film thicknesses decrease. The DLC film's wear-life is ∼600 cycles. The enhanced wear-resistance in PLC films is attributed to improvement of the crosslinking degree of the PLC network and the film compactness. [ABSTRACT FROM AUTHOR]

In this paper, the results of detailed X-ray photoelectron spectroscopy (XPS) studies combined with atomic force microscopy (AFM) investigation concerning the local surface chemistry and morphology of nanostructured ZnO thin films are presented. They have been deposited by direct current (DC) reactive magnetron sputtering under variable absolute Ar/O2 flows (in sccm): 3:0.3; 8:0.8; 10:1; 15:1.5; 20:2, and 30:3, respectively. The XPS studies allowed us to obtain the information on: (1) the relative concentrations of main elements related to their surface nonstoichiometry; (2) the existence of undesired C surface contaminations; and (3) the various forms of surface bondings. It was found that only for the nanostructured ZnO thin films, deposited under extremely different conditions, i.e., for Ar/O2 flow ratio equal to 3:0.3 and 30:3 (in sccm), respectively, an evident and the most pronounced difference had been observed. The same was for the case of AFM experiments. What is crucial, our experiments allowed us to find the correlation mainly between the lowest level of C contaminations and the local surface morphology of nanostructured ZnO thin films obtained at the highest Ar/O2 ratio (30:3), for which the densely packaged (agglomerated) nanograins were observed, yielding a smaller surface area for undesired C adsorption. The obtained information can help in understanding the reason of still rather poor gas sensor characteristics of ZnO based nanostructures including the undesired ageing effect, being of a serious barrier for their potential application in the development of novel gas sensor devices. [ABSTRACT FROM AUTHOR]

MgO thin film has a high secondary electron emission coefficient. However, the accumulation of electric charge on the surface of the thin film will inhibit it. This paper mainly discusses this phenomenon with the method of reactive magnetron sputtering. We prepared a MgO/Au buffer layer by co-sputtering Au in the inner layer of MgO. The experiments show that Au distributes mainly in the gap of the MgO grains. Adding appropriate Au will promote the growth of MgO grains in the longitudinal direction, increase the conductivity of the material, suppress the accumulation of electric charge on the surface, and increase the secondary electron emission coefficient of the thin film. NiO was also used as the transition layer of MgO and substrate in the experiments, so as to increase the adhesion of the MgO films and improve the quality of the thin film. According to the experiment results, the maximum secondary electron emission coefficient of MgOAu multilayer composite film increased by 28.9% compared with that of the pure MgO film. Under the continuous irradiation of 200 eV incoming energy, the decay rate decreased from 35.2% to 30.6% in 1 h. [ABSTRACT FROM AUTHOR]

In this study, the CrN x coatings were deposited by reactive magnetron sputtering at varying sputtering power from 200 to 300 W. The chemical composition, phase structure, surface and cross-sectional morphologies, and mechanical properties of the coatings were respectively investigated by electron probe microanalysis, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, and nano-indentation measurements. The results show that the coating deposited at a sputtering power of 200 W is a single-phase fcc CrN with columnar structure, while the coatings deposited at sputtering powers of 250 and 300 W are consisted of hexagonal Cr 2 N and fcc CrN with nano-composite structure. As compared with the single-phase Cr 2 N or CrN coatings, the composite coatings exhibit both higher hardness and superior resistance to plastic deformation and cracking, which is attributed to their unique nano-composite structure. [ABSTRACT FROM AUTHOR]

We investigate the mechanisms leading to the sulfurization of Cu, Zn, and Sn material during the deposition of Cu2ZnSnS4 (CZTS) films by reactive magnetron co-sputtering. We correlated the deposition parameters to the plasma composition determined by ion mass spectrometry. The behavior of Cu, Zn and Sn targets were studied depending on the H2S(g)/Ar(g) flow ratio and exhibit a transition regime to a compound mode in which stoichiometric films are grown. Mass spectrometry data reveal that Cu and Zn are preferentially deposited as a metal whereas Sn is condensed as a sulfide (SnxSy) due to the MS bond energy of the different compounds. Moreover, 45% of S contained in CZTS films is provided by the reaction between the reactive gas and the almost metallic growing film. [ABSTRACT FROM AUTHOR]

A narrow process window for the fabrication of p-type semiconductors is one of the major challenges in implementing tin oxide (SnO x ) in thin film transistor applications. The SnO x lattice was doped with Al to widen the process window and enhance the p-type channel thin film transistor performance with co-sputtering process. A change in the growth orientation direction with the presence of Al in SnO x thin films was observed in the grazing-incidence X-ray diffraction data. The changes in the oxidation states of Sn ions were determines by X-ray photoelectron spectroscopy. With increasing Al concentration, the ratio of Sn 4 + in the Sn peaks decreases indicating that the SnO x film has improved p-type properties. These changes led to an improvement of the electrical properties such as output characteristic, field effect mobility, subthreshold swing, and positive shift of threshold voltage. [ABSTRACT FROM AUTHOR]

W-Si-N films with various Si contents were deposited using a reactive magnetron system, and the film with the highest hardness, the lowest average friction coefficient (μ) and wear rate at room temperature (RT) was chosen to study the tribological properties at elevated temperature. Tribological properties of the film were performed using un-lubricated sliding tests against an alumina counterpart. Elevating the testing temperature from RT to 100 °C induced an intense skin plastic deformation, as a result, the μ increased rapidly and the wear rate decreased significantly. As the testing temperature was in the range of 100–200 °C, the surface deformation strengthening was induced furtherly, μ was further increased and the wear rate could not be calculated due the adhesive wear debris on the wear track. From 200 to 600 °C, the main wear mechanism changed to oxidation wear and the a lot of WO 3 tribo-film led to the decrease of μ. Wear rate increased gradually due to the accelerated oxidation of the film and the disappearance of surface deformation strengthening. [ABSTRACT FROM AUTHOR]

TiO 2 films were grown onto unheated 5083 aluminum alloy substrates by reactive magnetron sputtering from a pure Ti target in Ar-O 2 gas mixture in different power, bias voltage, Ar/O 2 ratio and deposition time at room temperature. The effects of different deposition parameters on the structure and properties of TiO 2 films were investigated systematically by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), nanoindentation tests, electrochemical tests and antibacterial tests. The results show that power and bias voltage are two main factors to affect the structure and properties of TiO 2 films during the sputtering process. XRD results show that anatase phase is the main phase of the film, and the enhanced content of anatase phase with the increase of sputtering power and bias voltage. Nanoindentation tests exhibit that higher H/E (Hardness/Modulus) ratio can be achieved by depositing TiO 2 film. And the corrosion resistance and antifouling property are all improved after depositing TiO 2 film. 2# sample shows the optimal corrosion resistance, E corr and I corr are −0.27388 V and 3.7232 μA/cm 2 , respectively. 1# sample exhibits excellent antibacterial property, the d ensity of bacteria is only 217 cell / mm 2 , which is 484% higher than that of uncoated matrix. [ABSTRACT FROM AUTHOR]

The effects of substrate temperature and O 2 flux on structural, electrical, and optical properties of the films prepared by RF reactive magnetron sputtering with SnF 2 -Sn target have been investigated by X-ray diffraction (XRD), Hall effect measurements, optical transmission spectra, and photoluminescence (PL) spectra. It is found that F-doped SnO films are produced and exhibit amorphous structure at lower O 2 fluxes for substrate temperature of RT-300 °C, and window of O 2 flux for depositing the films is reduced as substrate temperature increases. F-doped SnO 2 (FTO) films are formed at higher O 2 fluxes, and they exhibit amorphous state at substrate temperature of RT but crystalline state at substrate temperature of 150 and 300 °C. Furthermore, increasing O 2 flux or substrate temperature can promote crystallinity and affect growth orientation for crystalline FTO films. Highly conductive FTO films can be obtained only at suitable O 2 fluxes and higher substrate temperatures (150 and 300 °C), at which the films keep crystalline SnO 2 structure along with high amount of oxygen vacancy ( V O ). Increasing substrate temperature from 150 to 300 °C, the resistivity of FTO films cannot be further decreased due to the out-diffusion of F although the film crystallinity improves. Compared with F-doped SnO films, the average transmittance in visible light range and band gap ( E g ) of FTO films obviously increase. The FTO films show similar shaped PL spectra that can be attributed to substitutional fluorine ( F O ) and V O defects in the films, and PL emission intensity increases with increasing O 2 flux or substrate temperature due to the improvement of film crystallinity. It is observed that the PL emission characteristics (shape and intensity) of F-doped SnO film are obviously different from FTO films and they have great changes as substrate temperature from RT to 150 °C, but corresponding mechanisms need to further clarify. [ABSTRACT FROM AUTHOR]

A method for determining the electron temperature and electron density in a plasma is proposed that is based on minimization of the difference between the experimental relative intensities of the spectral argon (Ar) lines and those same intensities calculated with the aid of the collisional-radiative model. The model describes the kinetics of the ground state and 40 excited states of the Ar atom and takes into account the following processes: excitation and deactivation of the states of the atom by electron impact, radiative decay of the excited states, self-absorption of radiation, ionization of excited states by electron impact, and quenching of metastable states as a consequence of collisions with the chamber walls. Using the given method, we have investigated the plasma of a magnetron discharge on a laboratory setup for intermediate-frequency magnetron sputtering for a few selected operating regimes. [ABSTRACT FROM AUTHOR]

Reactive magnetron sputter deposition of transparent conductive oxides (TCOs) is a cost effective deposition technique due to low target costs compared to ceramic processes. Rotatable tube targets are used in industries because of their high material reservoir and a high target utilization (approx. factor 2 compared to planar targets). Another advantage for reactive sputtering is the absence of erosion groves. However, the reactive sputter process is highly complex because nearly any process parameter has strong impact on the properties of the growing film. Thus, the variation of the working point along the tube target may cause serious problems, in particular because conductivity, transparency, and thickness have to be optimized over a large substrate area at the same time. The most commonly sputtered TCO materials are aluminium doped zinc oxide and indium tin oxide. The respective reactive sputter processes are very distinct. This concerns among others the possible process control mechanisms as well as the dependence of the film properties on the reactive working point. The reliable industrial application of the reactive TCO sputter processes is still a big challenge for large area substrates. There are different possibilities to control the sputter process as well as the film properties in situ. [ABSTRACT FROM AUTHOR]

In this paper, yttrium was incorporated into titanium nitride matrix to deposit Ti Y O N films using a reactive magnetron sputtering system and the microstructure, mechanical and tribological properties were investigated. The results showed that solid solution face centered cubic (fcc) Ti Y N was the major phase of the film when the yttrium content was < 7.8 at.%. When the yttrium content was further increased, the film exhibited mixed phases of fcc-Ti Y N and amorphous yttrium oxide, this induced grain refinement and appearance of lots of grain boundaries. Hardness of the films first rose from 21 GPa at 0 at.% Y to 26 GPa at 10.2 at.% Y, and remained stable as the yttrium content was above 10.2 at.%. The hardness was influenced by the amorphous yttrium oxide phase, solid solution strengthening, grain boundaries and residual stress. Between 0 at.% to 7.8 at.% of yttrium, the fracture toughness (K IC ) rose slowly, K IC rose sharply to 0.85 MPa.m 1/2 as the yttrium content was 10.2 at.% due to the formation of amorphous yttrium oxide phase, it rose slowly again with a further increase in yttrium content. For the film at < 7.8 at.% Y, average friction coefficient (μ) and wear rate were influenced by the load significantly and there was an obvious rise in their values with an increase in load. A further increase in yttrium content in the films, improved the tribological properties, μ and wear rate were almost independent on the load. Fracture toughness enhancement attributed to the improved load capacity and tribological properties. [ABSTRACT FROM AUTHOR]

This work discusses an application of titanium oxide (TiO x ) thin films deposited using physical (reactive magnetron sputtering, RMS) and chemical (atomic layer deposition, ALD) vapour deposition methods as a functional coating for label-free optical biosensors. The films were applied as a coating for two types of sensors based on the localised surface plasmon resonance (LSPR) of gold nanoparticles deposited on a glass plate and on a long-period grating (LPG) induced in an optical fibre. Optical and structural properties of the TiO x thin films were investigated and discussed. It has been found that deposition method has a significant influence on optical properties and composition of the films, but negligible impact on TiO x surface silanization effectiveness. A higher content of oxygen with lower Ti content in the ALD films leads to the formation of layers with higher refractive index and slightly higher extinction coefficient than for the RMS TiO x . Moreover, application of the TiO x film independently on deposition method enables not only for tuning of the spectral response of the investigated biosensors, but also in case of LSPR for enhancing the ability for biofunctionalization, i.e., TiO x film mechanically protects the nanoparticles and induces change in the biofunctionalization procedure to the one typical for oxides. TiO x coated LSPR and LPG sensors with refractive index sensitivity of close to 30 and 3400 nm/RIU, respectively, were investigated. The ability for molecular recognition was evaluated with the well-known complex formation between avidin and biotin as a model system. The shift in resonance wavelength reached 3 and 13.2 nm in case of LSPR and LPG sensors, respectively. Any modification in TiO x properties resulting from the biofunctionalization process can be also clearly detected. [ABSTRACT FROM AUTHOR]

Composite TiN-Ag films with various Ag content (Ag/(Ti + Ag)) were deposited using reactive magnetron sputtering and the influence of Ag content on the crystal structure, mechanical and tribological properties were investigated. The result showed that face-centered cubic (fcc) TiN and fcc-Ag co-existed in the films and TiN had a columnar-growth and the Ag nanoparticles embedded in the boundary of columnar crystal. The hardness of TiN-Ag films initially increased gradually and reached an optimum value, and then decreased with an increase in Ag content in the films. The maximum hardness value was 29 GPa at 0.8 at.% Ag. The addition of Ag into TiN film could enhance the fracture toughness ( K IC ) and critical load ( L C1 ) of the films because the nanoparticle Ag provides a large volume fraction of grain boundaries. As Ag was added into TiN film, the average friction coefficient decreased from 0.78 at 0 at.% Ag to 0.20 at 41.1 at.% Ag; however, the wear rate of TiN-Ag films initially decreased and then increased, after reaching the minimum value of about 1.3 × 10 −7 mm 3 /(mm.N), at 0.8 at.% Ag. [ABSTRACT FROM AUTHOR]

Fe 2 O 3 doped silica films were deposited using a reactive cosputtering approach where the power applied to the Fe cathode was systematically varied from 20 to 80 W to change the Fe 2 O 3 content, while SiO 2 was deposited with a constant power of 100 W applied to the Si target. As a result of increases in Fe cathode power, from 20 to 80 W, the fraction of Fe 2 O 3 relative to SiO 2 was shown to increase from 0.01 to 0.15, as measured via x-ray photoelectron spectroscopy (XPS). XPS analysis was also used to analyze the valence states of the compounds present in the films, confirming the presence of both Fe 2 O 3 (Fe 3+ ) cations alongside SiO 2 (Si 4+ ). The observed increases in Fe 2 O 3 content were associated with a rise in refractive index values from n 589 = 1.48 to n 589 = 1.72, while the extinction coefficient, k 589 remained below 0.01. Films deposited using the methods outlined within this work demonstrate Eg values ranging from highly transparent at above 3.5 eV, down to 1.52 eV, within the range for devices requiring efficient absorption of solar energy. [ABSTRACT FROM AUTHOR]

CuCr0.93Mg0.07O2 thin films were successfully deposited by DC reactive magnetron sputtering at 1123K from metallic targets. The influence of film thickness on the structural and optoelectronic properties of the films was investigated. X-ray diffraction (XRD) results revealed that all the films had a delafossite structure with no other phases. The optical and electrical properties were investigated by UV-VIS spectrophotometer and Hall measurement, respectively. It was found that the optoelectronic properties exhibited a thickness-dependent behavior. The optical band gap and the average transmittance of the films showed a monotonous decrease with respect to the increase in thickness. The average transmittance in the visible region decreased from 67% to 47% as the thickness increased from ~70nm to ~280nm. Simultaneously, the conductivity of the films fell from 1.40S' cm-1 to 0.27S' cm-1. According to Haacke's figure of merit (FOM), a film with a maximum FOM value of about 1.72×10-7 -1 can be achieved when the thickness is about 70nm (σ 1.40S·cm-1 and Tav. 67%). [ABSTRACT FROM AUTHOR]

Giving paper and polymer photochromic properties under laser irradiation is challenging due to the low resistance of these materials to heat, their flexibility, and their possibly irregular structure. However, we could successfully deposit TiO2/Ag/ TiO2 layers stacking on flexible white glossy paper and transparent polyethylene terephalate (PET) substrates using a reactive magnetron sputtering technique, and tailor coloration changes after laser irradiation, alternating visible and ultraviolet (UV) wavelengths. The sample colors are characterized by a panel of chromas depending on the irradiation conditions. We demonstrate that these chroma changes are due to morphological changes of Ag nanoparticles (NPs) after visible laser irradiation of the colored as-deposited sample. The process exhibits a good reversibility after subsequent UV irradiation due to the growth of new metallic Ag NPs. The colors displayed in diffuse reflection by the paper samples are more saturated than the ones displayed in regular transmission by PET samples. We demonstrate the efficiency of the photochromic process on such support by printing high resolution patterns exhibiting different colors depending on the observation conditions. [ABSTRACT FROM AUTHOR]

A new method to prepare vanadium oxide with a high temperature coefficient of resistance (TCR) and low resistance for uncooled micro-bolometers has been proposed. Amorphous vanadium oxide films with V2O3 phase inclusions have been fabricated on silicon and silica substrates at the temperature 200 °C by using the direct current reactive magnetron sputtering method in controlled Ar/O2 atmosphere. Additional oxygen ion implantation in the deposited films allows to synthesize vanadium oxide with crystalline inclusions of VO2 and V2O5 phases under the low temperature annealing. The following long low-temperature annealing provides formation of VOx (at x → 2) film with the TCR close to 7.0%/°C. [ABSTRACT FROM AUTHOR]

Ti-Al-Si-Cu-N films were deposited on the AISI-304 stainless steel by reactive magnetron sputtering technology. The influences of the substrate temperature (deposition temperature) on the microstructure and properties of the films were researched by scanning electron microscope (SEM), energy disperse spectroscopy (EDS), X-ray diffraction (XRD), a nano-indenter, a scratch tester and a ball-on-disc rotational tribometer. The results indicate that when the deposition temperature increases from room temperature to 250 °C, the films become smoother and denser. The hardness and elastic modulus increase with the increase of the deposition temperature. The scratch tests show that when the deposition temperature is RT, 150 and 250 °C, the critical load of the films is 3.85, 3.45 and 5.10 N, respectively. The friction coefficient and wear rate of the Ti-Al-Si-Cu-N film deposited at 250 °C are the smallest, and the wear debris is mainly from the counterparts GCr15 stainless steel balls, The wear mechanism of the films deposited at lower temperatures is mainly fatigue fracture and abrasive wear, while that of the film deposited at 250 °C is abrasive wear. [ABSTRACT FROM AUTHOR]

W-Si-N composite films were deposited on both stainless steel and silicon wafers using a reactive magnetron system. The silicon content of the film was varied to evaluate the effect of silicon on films' elemental composition, microstructure, oxidation resistance, mechanical and tribological properties. These series of test were conducted using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM) analytical tools. The W-Si-N films showed a two-phase structure of solid solution face-centered cubic (fcc) W(Si)N x and an amorphous Si 3 N 4 . The thermal stability and the oxidation resistant temperature of W-Si-N films increased from about 380 °C at 0 at% Si to about 650 °C at 31.2 at% Si with the incorporation of Si into W 2 N matrix. The hardness of the films increased continuously from 26 GPa at 0 at% Si to 40 GPa at 23.5 at% Si which was due to solid strengthening and fine-grained strengthening. The silicon content affected the tribological properties of the film at room temperature but this was mainly influenced by the yield pressure, H/E ratio and elastic recovery, since lubricant tribo-film WO 3 was detected on all surfaces of the W-Si-N films. There was an initial gradual decrease in average coefficient of friction and wear rate until a minimum, but a further increase in silicon content resulted in increase in both friction coefficient and wear rates. The least coefficient of friction and wear rate values were 0.30 and 8.7 × 10 − 8 mm 3 /N·mm at 23.5 at% Si. [ABSTRACT FROM AUTHOR]

TiAlSiN nanocomposite coatings are obtained by the reactive magnetron sputtering of one-component targets with a widely varying (5-25) ratio of the ion current density j to the atomic flux density j on the sample surface. The plasma in the deposition chamber is generated by a broad (80 cm) low-energy (100 eV) electron beam. The beam current is varied from 5 to 30 A, which makes it possible to adjust j in the range of 1.8 to 9 mA/cm. It is shown that an increase in the ratio j / j is accompanied by a nonmonotonic variation in the hardness and texture of the coatings under the action of internal stresses. It is established that exceeding the value j / j at which the maximum hardness of the coating is reached (43 GPa) leads to the relaxation of intrinsic stresses and a reduction in the hardness to 36 GPa. [ABSTRACT FROM AUTHOR]

In this paper the preparation of nano-structured silver oxide thin films with different oxidation states with promise as electrode materials for supercapacitors by reactive magnetron sputtering is investigated. The chemical, structural, surface morphological dependence of the films on oxygen gas flow rate and deposition power were examined by scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX). The average thickness of the films was controlled in the range of ≈50–330 nm. The XRD spectra of the films indicated the formation of bi-phase films comprised of silver and silver oxides with different oxidation states. The wettability of the films in contact with different probing liquids was investigated by measuring the contact angles using a goniometer. It was shown that the silver oxide films are relatively hydrophilic and increasing oxygen flow rate increases the wettability of the films toward water as a result of an increase in the oxidation state of the films and consequently clustering of electrons in polar molecules of water around the oxides at higher oxidation states. This is further confirmed by the analysis of the surface energy measurements. [ABSTRACT FROM AUTHOR]

Ti-W-Al-N films with various Al content (0 at.% ∼ 12.4 at.%) were deposited by reactive magnetron sputtering. The composition, microstructure, mechanical and tribological properties of Ti-W-Al-N films were investigated by EDS, XRD, HRTEM, SEM, Nano-indentation, Ball-on-disk tribometer. It is found that Ti-W-Al-N films consist of Ti-W-Al-N phase, Ti 2 N phase and W 2 N phase below 2.9 at.% Al. Ti 2 N phase disappears at 5.6 at.% Al and h-AlN phase forms at 12.4 at.% Al respectively. The hardness firstly increases and then decreases with increasing Al content and the highest hardness is 35.7 GPa at 8.7 at.% Al. At room temperature, the friction coefficient continuously increases, whereas the wear rate firstly decreases and then increases with increasing Al content. The lowest wear rate of 1.79 × 10 −8 mm 3 N −1 mm −1 is obtained at 8.7 at.% Al. As the temperature increases from room temperature to 700 °C, the friction coefficient firstly increases and then decreases, while the wear rate gradually increases. The tribological properties of the film depended on the testing temperatures significantly because the testing temperatures influenced the hardness, the tribo-films and wear mechanism of the film. [ABSTRACT FROM AUTHOR]

Ti-Al-Si-Cu-N nanocomposite films with different Cu contents were deposited on AISI-304 stainless steel by DC reactive magnetron sputtering. Both Ti-Al-Si-N and Ti-Al-Si-Cu-N nanocomposite films were oxidized at 800 °C to investigate the influence of Cu content on the microstructure and high temperature oxidation resistance by scanning electron microscope (SEM), energy disperse spectroscopy (EDS), X-ray diffraction (XRD), nanoindentation tester and a home-made indentation system. The results indicate that with the increasing copper content in the films, the micropores disappear on the surface of Ti-Al-Si-N nanocomposite film and compact films are obtained. A reduction of the grain size and a change of the (111) preferred orientation to (110) are observed. The microhardness of films increases from 14.76 GPa to 19.42 GPa. The elasticity modulus of Ti-Al-Si-Cu-N films with 1.72 at% Cu content is the minimum of 104.5 GPa. The incorporation of copper at high temperature influences the oxidation resistance of the Ti-Al-Si-N films in the two aspects, one is advancing the diffusion rate of Al element, and the other is inducing cracks of oxide layer and micropores. Ti-Al-Si-N films have a better oxidation resistance than that of the films added Cu element. [ABSTRACT FROM AUTHOR]

As a type of electron-induced secondary electron emitter, MgO/Au composite thin film was prepared by reactive magnetron sputtering of individual Mg target and Au target, and the effects of key process parameters on its surface morphology and secondary electron emission (SEE) properties were investigated. It is found that to deposit a NiO buffer layer on the substrate is conducive to the subsequent growth of MgO grains owing to the lattice matching. The gold addition can raise the electrical conductivity of MgO film and further suppress the surface charging. However, the gold deposition would interfere with the MgO crystallization and increase the surface roughness of MgO/Au film. Therefore, MgO/Au composite thin film with a NiO buffer layer and proper deposition times of MgO and Au can achieve superior SEE properties due to good MgO crystallization, low surface roughness and reasonable electrical conductivity. The optimized MgO/Au composite thin film has a higher SEE coefficient and a lower 1-h SEE degradation rate under electron beam bombardment in comparison with MgO film. [ABSTRACT FROM AUTHOR]

Nanocomposite thin films with TiN dispersed in Ni matrix were deposited in an environment having Ar:N 2 = 1:2 on silicon (100) substrate with bias of − 60 V at 300 °C, 500 °C or 700 °C by co-sputtering of Ti and Ni targets used as RF and DC sources, respectively. The structure and properties of these films were compared with those deposited at ambient temperature and then annealed for 1 h in vacuum at above-mentioned temperatures. Whereas < 111 > is the preferred orientation of Ni, transition from < 100 > to < 111 > is observed for TiN at temperatures ≥ 500 °C, as confirmed by XRD analyses. The average grain sizes of Ni and TiN have been found to be in the ranges of 11–25 nm and 6–13 nm, respectively, using both XRD and TEM studies. Transition from compressive to tensile residual stress is observed with increase in substrate temperature for deposition or annealing. Hardness, elastic moduli and scratch-resistance of the films evaluated using a nanoindentor are found to possess the most optimum values on their growth at substrate temperature of 300 °C. [ABSTRACT FROM AUTHOR]

Niobium carbide (NbC) catalytic films were deposited on the surface of vanadium (V) substrates by reactive magnetron sputtering (RMS) using CH 4 as the carbon source to form the NbC/V composite membranes for hydrogen separation and purification. The effects of CH 4 gas flow ratio (F CH4 = CH 4 /(CH 4 +Ar)) on the phase structure, surface microstructure and catalytic properties of NbC films and the hydrogen permeation performance of the NbC/V composite membranes were investigated. The results showed that the structure of the NbC catalytic film changed from the dual-phase of NbC and Nb 2 C to the single-phase of cubic NbC after the addition of CH 4 gas. Furthermore, with the increase of F CH4 , the carbon content in the NbC catalytic films increases, but the crystallinity decreases. When F CH4 is 5%, the hydrogen permeation performance of the NbC/V composite membrane is the highest, which is attributed to the appropriate carbon content and crystallinity of the NbC phase. Typically, the hydrogen permeability is 7.0 × 10−8 mol H 2 m−1 s−1 Pa−0.5 at 650 °C, which is 2.4 times that of pure Pd. • After the addition of CH 4 gas, the structure of NbC film is the single NbC phase. • The CH 4 gas flow ratio significantly affects the performance of NbC/V membranes. • The highest H 2 permeability of NbC/V membranes is 2.4 times that of pure Pd. • NbC/V membranes exhibit high hydrogen permeation stability at high temperatures. [ABSTRACT FROM AUTHOR]

• Epitaxial (111) TiC film was deposited on 4° off-angle 4H-SiC (0001) by sputtering. • The FWHM of X-ray rocking curve of TiC (111) is 0.039°. • TiC film with a low resistivity in 80 μΩ⋅cm can be obtained. • Growth of a thick film may result in formation of a relaxed top layer. Heteroepitaxial TiC films were grown on semi-insulating (0001) 4H-SiC substrates at high temperature by using direct current (DC) magnetron reactive sputtering. The effect of the CH 4 flux ratio in Ar on the crystalline quality of the films was investigated. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that the deposited TiC films are heteroepitaxially grown on 4H-SiC substrates with the heteroepitaxial relationship between TiC and 4H-SiC in (111) TiC // (0001) 4H-SiC and [1 1 ¯ 0] TiC // [11 2 ¯ 0] 4H-SiC. The full width at half-maximum (FWHM) of X-ray rocking curve (XRC) of (111) TiC reflection can reach a minimum value of 0.039° and the resistivity of TiC film can be ∼ 80 μΩ⋅cm for deposition at 700 °C with 4% CH 4 flow ratio. X-ray photoelectron spectroscopy (XPS) shows that the composition of TiC film is nearly in stoichiometry for 4% CH 4 flow ratio. From the TEM results, it is observed that the TiC film is divided into a strained layer and a relaxed layer when the film thickness reaches a critical value over about 70 nm. [ABSTRACT FROM AUTHOR]

• Ion-assisted reactive magnetron sputtering was introduced for deposition. • Silicon nitride with tunable refractive index was used for antireflection coatings. • Effective anti-reflection for each sub-band and optical communication band. • Average reflection of coatings was less than 0.75%, with a minimum of 0.19% • Coatings featured high deposition quality with roughness below 0.5 nm. With the rapid development of silicon-based photonics, broadband anti-reflection coatings for the optical communication band are desired. Silica and silicon nitride with tunable refractive index were employed in anti-reflection coatings, which were deposited by ion-assisted reactive magnetron sputtering. The results showed that the average reflectance of 0.74% for single-layer coatings and below 0.12% after optimization for each sub-band. With the insertion layer, the anti-reflection band broadened and covered the optical communication band. Multi-layer coatings' average reflectance was reduced to within 0.35%, with only 0.19% for four-layer coatings. Both single-layer and multi-layer coatings exhibited impressive deposition quality. For single-layer and multi-layer coatings, no obvious defects were found on the surface and cross-sectional morphology, and the roughness remained within 0.5 nm. In this work, anti-reflection coatings were deposited by ion-assisted reflective magnetron sputtering, featuring broadband low reflectance and high deposition quality, which is suitable for serving optical communication devices such as photodetectors and wide-tunable lasers. [ABSTRACT FROM AUTHOR]

Thin films of iridium oxide are deposited by reactive magnetron sputtering. The influence of oxygen partial pressure in the sputtering plasma on the composition, surface structure and morphology of the films has been studied by XRD, SEM, AFM and XPS analysis. An optimal combination of sputtering parameters yields stable microporous amorphous films with highly extended fractal surface. The electrochemical properties of these films are investigated in view of their application as catalysts for PEM water splitting, using the electrochemical techniques of cyclovoltammetry and steady state polarization. A morphology factor assessing the catalyst active surface for a series of sputtered samples with varying thickness/loading is determined and correlated to the catalytic efficiency. It has been proven that iridium oxide is a very efficient catalyst for oxygen evolution reaction (OER). The best performance with anodic current density of 0.3 A cm–2; at potential of 1.55 V (vs. RHE) shows the 500 nm thick film containing 0.2 mg cm-2; catalyst. These results combined with the established long-term mechanical stability of the sputtered iridium oxide films (SIROFs) prove the advantages of the reactive magnetron sputtering as simple and reliable method for preparation of catalysts with precisely controlled composition, loading, and surface characteristics.

Silicon nitride films were deposited by reactive magnetron sputtering, during which ion assistance was introduced. The results showed that the optical properties and composition were significantly affected by ion assistance. The refractive index was decreased from 2.87 to 2.17, and the extinction coefficient was decreased from 0.1535 to 0.0031 (@492 nm). The nitrogen-to-silicon ratio was increased from 0.612 to 0.955 by ion assistance, shifting from silicon-rich to near-stoichiometric. Not only that, the ion-assisted film featured lower roughness and less impurity. As the ion source power increased, the Raman peaks of silicon and silicon oxide decreased as well. In this work, ion assistance exhibits a considerable effect on silicon nitride films, which has potential applications in the processing of silicon nitride films and other semiconductor thin films. • Ion-assisted reactive magnetron sputtering was introduced into silicon nitride film. • The ratio of nitrogen to silicon increased from 0.612 to 0.955 with ion assistance. • Refractive indies of films reduced from 2.87 to 2.17 at 492 nm with ion assistance. • Roughness and impurities in silicon nitride films reduced with ion assistance. • No significant flaws were introduced in films with ion assistance. [ABSTRACT FROM AUTHOR]

This research describes the synthesis of multilayer thin films of aluminum oxide and tantalum oxide for dielectric applications. The multilayer thin films are made of two, four, or eight oxide layers produced by physical vapor deposition (PVD), specifically mid-frequency pulsed direct current magnetron sputtering. The oxide layers are stoichiometric Al 2 O 3 and Ta 2 O 5 with two specific morphologies observed from cross-section images obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Al 2 O 3 layers exhibit a columnar structure whereas the Ta 2 O 5 layers are uniform and dense. However, the morphology of the Ta 2 O 5 layers changes progressively in the four-layer and eight-layer systems under the influence of the morphology of the Al 2 O 3 layer below. This behavior is induced by the morphological continuity of the interface between two oxide layers. X-ray diffraction (XRD) shows the low crystallinity of these oxide layers due to the experimental conditions used during the magnetron sputtering process, particularly the low deposition temperature. The dielectric behavior of the multilayer thin films is studied by dielectric strength measurements. The results are compared to the values obtained for single layers of Al 2 O 3 and Ta 2 O 5 produced under the same experimental conditions. The two-layer system shows an intermediate value compared to the single layers, higher than Al 2 O 3 and lower than Ta 2 O 5. The dielectric strengths of the four-layer and the eight-layer systems are higher than those measured for the single layers of Al 2 O 3 and Ta 2 O 5. Finally, the morphology and the crystallinity of the multilayer thin films are changed by thermal annealing of these samples at 850 °C under vacuum. The thermal annealing induces crystallization of the Ta 2 O 5 layers and the loss of morphological continuity at the interface between the oxide layers. These modifications result however in a lower dielectric strength for all the multilayer thin films. • Multilayer thin films made of two, four, or eight layers alternating Al 2 O 3 and Ta 2 O 5. • Low crystallinity and characteristic morphology of stoichiometric oxide layers. • Improved dielectric strength due to the interfaces in the multilayer systems. • The dielectric strength of multilayer oxide thin films is temperature sensitive. [ABSTRACT FROM AUTHOR]