A magnetron discharge with a zirconium cathode is operated in an argon/oxygen gas mixture. The magnetron is operated in pulsed mode with repetition frequencies of 0.5–5 kHz and in radiofrequency mode. Positively charged atomic O+, Ar+, and Zr+ and molecular O2+, ArO+, Ar2+, ZrO+ and ZrO2+ are observed. Negatively charged O− ions sputtered from the magnetron’s cathode are investigated in some detail. The intensity of negatively charged O− is strongly influenced by the repetition rate. Formation of excited Ar, Ar+, Zr, and Zr+ species is influenced by target poisoning. Target poisoning reduces the deposition rate by one order of magnitude. Zirconium dioxide films are either deposited at room temperature followed by post-deposition annealing or on heated Si substrates. Deposited films are characterised by means of X-ray diffractometry (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy, infrared ellipsometry, and spectroscopic optical ellipsometry. XRD confirms the monoclinic lattice phase of the films. The ultra-wide bandgap of the deposited zirconia films is confirmed by spectroscopic ellipsometry measurements. Two direct optical bandgaps at 5.25 eV and 6.1 eV are extracted from the measurements.

The energy distribution of negatively and positively charged ions in a magnetron discharge is investigated. A zinc cathode operated in an argon/oxygen gas mixture is employed. The magnetron is operated in the pulsed mode with repetition frequencies of 10–30 kHz. Positively charged atomic O+, Ar+, and Zn+ ions, molecular O2+, ArO+, Ar2+, ZnO+, and ZnO2+, and doubly charged Ar2+ ions and negatively charged O−, O2−, ZnO−, and ZnO2− ions are observed. Negatively charged ions either form inside the plasma volume by electron attachment reactions or are sputtered from the negatively biased cathode and as such receive high kinetic energies corresponding to the cathode potential. The intensity of the negatively charged O− strongly depends on the plasma parameters, in particular, the repetition rate. Zinc oxide films are deposited at room temperature at repetition frequencies of 10–30 keV. The deposited films are characterized by means of scanning electron microscopy, x-ray diffractometry, photothermal deflection spectroscopy, optical and infrared ellipsometry, Fourier-transform infrared and Raman spectroscopy, and photoluminescence. These films are highly oriented along the surface normal and are highly transparent in the visible spectral region. The extracted optical bandgap and Urbach energy are about 3.3 eV and 62 meV, respectively.

Cobalt nickel oxide films are deposited on Si(111) or fluorine-doped tin-oxide-coated (FTO) glass substrates employing a pulsed hollow-cathode discharge. The hollow cathode is operated with argon gas flowing through the nozzle and with O2 gas admitted to the vacuum chamber. Three different cathode compositions (Co20Ni80, Co50Ni50, and Co80Ni20) are investigated. Deposited and annealed thin films are characterized by X-ray diffraction, infrared (Raman) spectroscopy, and ellipsometry. As-deposited films consist of a single mixed cobalt nickel oxide phase. Upon annealing at 600 °C, the mixed cobalt nickel oxide phase separates into two cystalline sub-phases which consist of cubic NiO and cubic Co3O4. Annealed films are investigated by spectroscopic ellipsometry and the optical bandgaps are determined.

A hollow cathode discharge with a CuNi (Cu50Ni50) cathode is operated inside a vacuum chamber with Ar gas flowing through its nozzle. O2 gas is admitted to the vaccum chamber. Typical Ar+O2 gas pressures are in the range of 2–50 Pa. The energy distribution of plasma ions is investigated with the help of energy-resolved mass spectrometry. Singly charged Ar+ and molecular O2+ ions are the most abundant ionic species. Deposition rate and heat flux to a substrate increase as function of discharge current. At high pressures, the deposition rate is further increased by the directional gas flow, which becomes more focused onto the substrate. Deposited and annealed thin films are analysed by X-ray diffraction and Raman spectroscopy. As-deposited films are composed of a mixed CuxNi1−xO cubic phase with a preferred (111) orientation. Upon annealing at 600 oC, the mixed CuxNi1−xO phase separates into two sub-phases composed of NiO and CuO. Annealed films display a photoelectrochemical (PEC) activity as a photocathode. The PEC activity deteriorates with time, however. This behaviour is related to the reduction of CuO to Cu2O.

Electrochemically active ϵ-MnO2 and ɣ-MnO2 as tunnel-type host-guest structures have been extensively studied by crystallography and electrochemical techniques for application in battery cathode materials. However, the Gibbs energies of the underlying ion and electron transfer processes across the electrode interfaces have not yet been determined. Here we report for the first time these data for ϵ-MnO2 . This was possible by measuring the mid-peak potentials in cyclic voltammetry and the open-circuit potentials under electrochemically reversible conditions.

The practical applicability of ultrathin films, which offer interesting and novel functionalities, is often hampered by difficulties in large-area deposition while maintaining homogeneous film properties. Here, we induce a breakup after forced wetting to produce the ultrathin film [Runde, S. et al. Adv. Mater. Interfaces 2018, 5(16), 1800323] and apply this deposition method to selected liquid metals and alloys to produce electrically conductive films at ambient conditions on wafer-scaled areas. In addition to ultrathin monolayers, vertically stacked and heterostructured multilayers of metal and metal hydroxide can be built by repeating the deposition method. Structural analysis using X-ray reflectometry shows that the multilayer thickness is proportional to the number of deposition cycles, yielding a single layer thickness between 2.9 and 5.2 nm, depending on the material used. Every single layer consists of a complex heterostructure composed of a nanometer-thin metallic core surrounded by stabilizing metal (hydr)oxide skin layers. The crystallinity of the layers within the films was investigated with grazing incidence X-ray diffraction; X-ray amorphous materials were Ga, GaIn(1:1), and GaInSn(7:2:1), which also showed low optical absorbance and low electrical resistivity. Films made from InSn(1:1)- and Bi-containing alloys showed weak diffraction peaks, indicating partial crystallization. The electrical conductivity of all multilayers increases with the number of deposition cycles, allowing to fine-tune the sheet resistance. The preparation of ultrathin multilayers of metallic materials at the centimeter scale is attributed to the low melting temperature combined with the high surface tension and wettability of the liquid metals.

The lateral movement in lipid membranes depends on their diffusion constant within the membrane. However, when the flux of the subphase is high, the convective flow beneath the membrane also influences lipid movement. Lipid monolayers of an unsaturated fatty acid at the water–air interface serve as model membranes. The formation of domains in the liquid/condensed coexistence region is investigated. The dimension of the domains is fractal, and they grow with a constant growth velocity. Increasing the compression speed of the monolayer induces a transition from seaweed growth to dendritic growth. Seaweed domains have broad tips and wide and variable side branch spacing. In contrast, dendritic domains have a higher fractal dimension, narrower tips, and small, well-defined side branch spacing. Additionally, the growth velocity is markedly larger for dendritic than seaweed growth. The domains’ growth velocity increases and the tip radius decreases with increasing supersaturation in the liquid/condensed coexistence region. Implications for membranes are discussed.

We report the surface stoichiometry of Tix-CuyNz thin film as a function of film depth. Films are deposited by high power impulse (HiPIMS) and DC magnetron sputtering (DCMS). The composition of Ti, Cu, and N in the deposited film is investigated by X-ray photoelectron spectroscopy (XPS). At a larger depth, the relative composition of Cu and Ti in the film is increased compared to the surface. The amount of adventitious carbon which is present on the film surface strongly decreases with film depth. Deposited films also contain a significant amount of oxygen whose origin is not fully clear. Grazing incidence X-ray diffraction (GIXD) shows a Cu3N phase on the surface, while transmission electron microscopy (TEM) indicates a polycrystalline structure and the presence of a Ti3CuN phase.

Analysis of liquids performed in multiple domain, e.g., optical and electrochemical (EC), has recently focus significant attention. Our previous works have shown that a simple device based on indium-tin-oxide (ITO) coated optical fiber core may be used for optical monitoring of EC processes. At satisfying optical properties and thickness of ITO a lossy-mode resonance (LMR) effect can be obtained and used for monitoring of optical properties of an analyte in proximity of the ITO surface. However, EC response of the ITO-LMR device to a redox probe has not been achieved for ITO-LMR sensor whereas it is generally observed for commercially available ITO electrodes. The changes in the response to a redox probe are typically used as a sensing parameter when EC label-free sensing is considered, so it is crucial for further development of combined LMR-EC sensing concept. In this work, we focus on enhancing the EC activity of the device by tuning ITO magnetron sputtering deposition parameters. Influence of the deposition pressure on the ITO properties has been the main consideration. Both optical and EC readouts in 0.1 M KCl containing such redox probes as 1 mM of K-3[Fe(CN)(6)] or 1 mM 1,1'-Ferrocenedimethanol were discussed at different scan rate. The performed studies confirm that for optimized ITO properties the ITO-LMR sensor used as the EC electrode may also show excellent EC performance. The observed EC processes are quasi-reversible and diffusion-controlled. Moreover, for the devices, which offer improved EC response, an optical monitoring of the EC process is also possible. According to our best knowledge, fully functional combined optical and EC sensor, where optical effect is resonance-based and other than well-known surface plasmon resonance, is presented for the first time.

The effect of argon ion beam etching and subsequent annealing on the surface morphology and electrochemical response of poly- and monocrystalline gold electrodes was studied with the help of scanning electron microscopy, cyclic voltammetry and measurements of under-potential deposition of lead. While the samples were cleaned and restructured by the argon ion beam the following thermal treatment produced stable and very smooth highly ordered surfaces. The specific behaviour of polycrystalline and monocrystalline gold surfaces is discussed.

The lack of efficient cost-effective electrocatalysts for reversible oxidation of water is by far the most notorious obstacle in the development of fuel cells and electrolyzers. Here, oxygen bifunctional electrocatalysts based on C-CoFe and C-NiFe oxide nanospinels are developed by simple autocombustion between ethylene glycol/acetate and the metal nitrates. The effects of electronic modulation and the mass (or surface area) effect were examined based on the cyclic voltammograms of the unary and binary metal oxides in alkaline solution, and their high oxygen evolution and reduction activities were attributed to the synergic intermetallic interactions. The C-CoFe oxide, in particular, shows an oxygen evolution overpotential of 350 mV (without iR correction) at 10 mA cm(-2) with excellent stability over 10 hours and a Tafel slope of 49 mV per decade. Furthermore, it exhibits the highest oxygen reduction activity among the synthesized electrocatalysts due the particular synergy between Co and Fe centers.

We report the surface stoichiometry of cubic Cu3N films as function of nitrogen concentration (N/Cu). The film is deposited at 1Pa showing self-buckled (surface peels off) effect as it is exposed to ambient air at atmospheric pressure whereas at 5 Pa, the film shows no such effect. The spectroscopic (X-ray photoelectron spectroscopy (XPS)) analysis suggests that the presence of nitride layer is not the prime cause but the surface oxidation playing a major role for the self-buckling effect. Grazing incidence X-ray diffraction (GIXRD) confirms the formation of a crystalline Cu3N phase of the film. Atomic force microscopic (AFM) study reveals that the 1Pa film shows a lower roughness as compared to 5 Pa films and furthermore, Fast Fourier Transform (FFT) analysis shows a fourfold symmetric structure (both modes of pattern-orientation) in both the deposited films.

A thermal atomic layer deposition (ALD) process for depositing titanium phosphate onto bundles of carbon fibers as well as flat silicon and germanium substrates using titanium tetrachloride and triethyl phosphate as precursors is presented. This process yields conformal coatings on all substrates used while having a growth per cycle of 0.22 nm cycle(-1), which is relatively high compared to other metal phosphate ALD processes. The reactions of the precursors with the surface are shown to be self-limiting at 200 degrees C. Compositional analysis of the coating is performed using energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. It is shown that the as-deposited coating has a chemical composition of Ti3.0PO8.2 and a residual carbon content of 7%. Upon thermal annealing in air, residual triethyl phosphate and water is lost from the coating and phosphate can be identified up to 1000 degrees C. At temperatures exceeding 1000 degrees C, the coating starts to decompose. Thermogravimetric analysis of coated carbon fibers shows that the coating increases the onset temperature of the carbon fiber oxidation, thus providing an oxidation protection to the fibers.

The voltammetric behavior of polycrystalline gold electrodes in 0.1 M sulfuric acid and the influence of prolonged repetitions of oxidation and reduction cycles at different scan rates on the surface morphology was studied. Slow (0.1 Vs(-1)) as well as fast (1.0 Vs(-1)) scan rates lead to an intense roughening of the electrode surface and the formation of a variety of different crystalline particles on it. These crystallites, their formation, and the influence of surface pretreatment were investigated with electrochemical methods, X-ray diffraction measurements, and scanning electron microscopy. Additionally, an interpretation of the changing electrochemical signals of polycrystalline gold during prolonged potential cycling is given.

We report the self-buckling (or peeling off) of cubic Cu3N films deposited by DC magnetron sputtering of a Cu target in a nitrogen environment at a gas pressure of 1 Pa. The deposited layer partially peels off as it is exposed to ambient air at atmospheric pressure, but still adheres to the substrate. The chemical composition of the thin film as investigated by means of X-ray photoelectron spectroscopy (XPS) shows a considerable surface oxidation after exposure to ambient air. Grazing incidence X-ray diffraction (GIXRD) confirms the formation of a crystalline Cu3N phase of the quenched film. Notable are the peak shifts in the deposited film to smaller angles in comparison to stress-free reference material. The X-ray pattern of Cu3N exhibits clear differences in the integral width of the line profiles. Changes in the film microstructure are revealed by X-ray diffraction, making use of X-ray line broadening (Williamson–Hall and Stokes–Fourier/Warren–Averbach method); it indicates that the crystallites are anisotropic in shape and show remarkable stress and micro-strain.

The paper reports controlled deposition of optically transparent and electrically conductive ITO films prepared by a combination of rf (13.56MHz) and High Power Impulse Magnetron Sputtering (HiPIMS) systems without any post deposition thermal treatment/annealing. It is shown that (i) reactive admixture of N2 gas to the process and (ii) pressure in the deposition chamber enable to optimize optical properties of ITO films. Furthermore, the changes of electrical resistivity were observed, too. The variation of these ITO properties is attributed to change of crystalline structure measured by XRD methods.

Metal nanoparticles embedded into a semiconductive matrix represent a promising material for widely sought advanced technological applications. We focused our interest on the preparation of TiO2 matrix with embedded Cu nanoparticles. In particular, we studied the effect of reactive discharge (Ar/O2) exposition on copper oxidation, which can result in two stable forms: cuprous oxide (Cu2O) and cupric oxide (CuO). Copper nanoparticles, of size in range 10–50 nm, were produced by magnetron sputtering in combination with gas aggregation. The beam of Cu nanoparticles was impinging onto a silicon substrate which was directly exposed to a reactive Ar/O2 magnetron discharge providing sputtering of Ti target at the same time. The properties of deposited nanocomposite Cu(xO)–TiO2 were investigated by X-ray photoelectron spectroscopy, grazing incidence X-ray diffractometry, X-ray reflectometry and scanning electron microscopy techniques to reveal the nanocomposite properties and to understand the oxidation process of embedded Cu nanoparticles. It was found that CuO is preferentially formed if copper is exposed to active oxygen species (O+, O−, O⁎ etc.) produced in the reactive magnetron discharge. On the other hand, Cu2O was observed in the case of copper reaction in ambient Ar/O2 atmosphere. As a result, two possible copper oxidation mechanisms are proposed, employing chemical kinetics.

A tungsten wire covered with Na0.75WO3 acts in potentiometry as a reversible pH electrode having a pH dependent open-circuit potential Eocp with nernstian slope. The mid-peak potential Emp of cyclic voltammograms also depends on pH. At low pH (e.g., pH2) and slow scan rates (e.g., 2mVs–1) the voltammetric response is almost completely reversible. At higher pH and faster scan rates, the voltammetric systems exhibit features of increasing irreversibility. Under the conditions of reversibility, the Eocp and Emp differ significantly. Eocp is determined by the proton transfer at the electrode surface; whereas Emp is determined by the electron transfer equilibrium tungsten(VI)/tungsten(V) and the proton transfer at the electrode surface. The difference between Eocp and Emp provides the individual thermodynamic contributions of electron and proton transfer to the overall pH dependent redox electrode. This is the first time that both contributions can be separated for an insertion electrochemical system (thin surface layer). It is also shown for the first time that the mechanism of an ion-sensitive electrode can differ in potentiometry and voltammetry.

The purpose of this work was to deposit Zn-containing films on Si substrates using the commercial atmospheric pressure plasma jet "kINPen'09." In preliminary experiments Zn-containing films were deposited on the silicon substrates immersed in water solutions of Zn(NO3)(2)center dot 6H(2)O salt. The surface composition of deposited films was analyzed by the XPS (X-ray photoelectron spectroscopy) technique while the bulk composition was studied by means of XRD (X-ray diffraction) mesurements. The film thickness was measured by a profilometer. We have determined that the concentration of the zinc nitrate solution as well as changes in the deposition time resulted in a large fluctuation of the deposited film thickness. However, the successful deposition of the Zn-containing films on the Si substrate was definitely confirmed.