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Next-generation superconducting radio frequency (SRF) cavities, based on tailored thin films, would allow for more efficient and sustainable accelerators operating at higher accelerating gradients. In particular, superconductor–insulator–superconductor (SIS) multilayers are proposed as a potential alternative to bulk Nb. In this context, NbTiN stands out as a superconducting candidate. Here, we report our studies on NbTiN thin films grown by plasma-enhanced atomic layer deposition (PEALD) in a supercycle approach on AlN in situ deposited on planar silicon substrates. In detail, different ternary compound compositions and thicknesses have been investigated concerning the elemental composition, the superconducting properties, and the crystallinity of the deposited thin films. Two different post-deposition thermal treatments have been applied to Nb0.75Ti0.25N thin films of different thicknesses. Their effect on the film properties has been evaluated. It has been demonstrated that an optimized post-deposition thermal annealing procedure significantly improves the quality of our PEALD deposited Nb0.75Ti0.25N thin films, achieving the highest superconducting critical temperature (Tc) of 15.9 K obtained for films deposited by atomic layer deposition (ALD) so far and a lower critical field (Hc1) of 213 mT, which overpasses the bulk Nb intrinsic limit of 200 mT. Our studies are a promising first stepping stone on the path toward tailored thin films based SRF cavities. [ABSTRACT FROM AUTHOR]

A simple approach dealing with thermal oxidation at atmospheric pressure was used to synthesize copper oxide nanowires (CuO-NWs) on copper substrate. The vertically oriented CuO-NWs were used for further subjected to deposition of ultrathin layer (∼20 nm) of lanthanum hexaboride (LaB 6) using the electron beam evaporation technique. The observation of the characteristic vibrational mode of LaB6 in the Raman spectrum of LaB6-coated CuO-NWs (LaB6@CuO-NWs) revealed the existence of LaB6 in the deposited sample. Furthermore, confirmation of LaB6 coating on CuO-NWs was corroborated by X-ray photoelectron spectroscopy (XPS) analysis. The field electron emission (FEE) characteristics of pristine CuO-NWs and LaB6@CuO-NWs were investigated in a planer diode geometry at a base pressure of ∼ 1 × 1 0 − 8 mbar. The values of turn-on and threshold fields (defined at emission current density of 1 and 10 μ A/cm2, respectively) were found to be 5.4 V/ μ m and 1.6 V/ μ m (for pristine CuO-NWs emitter) and 6.75, and 2.85 V/ μ m (for LaB6@CuO-NWs emitter). Interestingly, a noticeably large emission current density of ∼ 1 6 7 5 μ A/cm2 has been extracted from the LaB6@CuO-NWs emitter at a relatively lower applied field of 5.8 V/ μ m. The Fowler–Nordheim (FN) plots of both the emitters showed nonlinear behavior, indicative of their semiconductive nature. Furthermore, both the emitters showed relatively stable emission behavior tested at a pre-set value of 1 μ A more than 3 h. The enhanced FEE behavior of LaB6@CuO-NWs emitter is attributed to the modulation of electronic properties due to LaB6-CuO interface-induced effects. Although the promising FEE behavior of LaB6@CuO-NWs emitter warrants its potential for practical applications, further improvement can be achieved via fabricating an array emitter due to CuO NWS and optimizing the thickness of LaB6 coating. [ABSTRACT FROM AUTHOR]

Polymer nanocomposite films based on poly(vinyl pyrrolidone) incorporated with different amounts of copper oxide (CuO) nanoparticles were prepared by the solution casting technique. The PVP/CuO nanocomposites were analyzed by X-ray diffractometry (XRD), scanning electron microscopy, UV–Visible absorption spectroscopy and dielectric spectroscopy. The XRD analysis showed that the monoclinic structure of cupric oxide was maintained in the PVP host matrix. The key optical parameters, such as optical energy gap Eg, Urbach energy EU, absorption coefficient and refractive index, were estimated based on the UV-Vis data. The optical characteristics of the nanocomposite films revealed that their transmittance and absorption were influenced by the addition of CuO nanoparticles in the PVP matrix. Incorporation of CuO nanoparticles into the PVP matrix led to a significant decrease in band gap energy and an increase in the refractive index. The dielectric and electrical behaviors of the PVP/CuO nanocomposites were analyzed over a frequency range between 10 Hz and 1 MHz. The effect of CuO loading on the dielectric parameters (dielectric constant and dielectric loss) of the metal oxide nanocomposites was also discussed. [ABSTRACT FROM AUTHOR]

Herein, we report on the post-annealing temperature effect on the transport behavior of p-CuO/Al Schottky barrier diodes. In addition, the transformation of phase from Cu4O3 to CuO phase was studied. Copper oxide thin films were grown on soda lime glass substrates, and post-annealing temperature's influence on the films' structural, chemical, morphological, and electrical characteristics was comprehensively examined. X-ray diffraction study revealed the development of polycrystalline tenorite phase (CuO) on annealing. Raman analysis also confirmed the formation of the tenorite phase (CuO) at higher annealing temperatures (400 °C and 500 °C). XPS study revealed the occurrence of the Cu4O3 phase for room temperature deposited sample and CuO phase at the higher annealing temperature. Using current–voltage analysis, the Chueng model, and the thermoelectric emission model, the Schottky behavior between the metal and semiconductor were investigated. The fabricated diode showed a rectification ratio of 103 at ± 2 V, with the barrier height ranging from 0.84 to 1.12 eV due to different annealing treatments. The attributes of the power law were employed to elucidate space charge-limited conduction and the process of tunneling across the density of interface traps in p-CuO/Al Schottky diodes. This study provides valuable insights into the behavior of the p-CuO/Al Schottky junction, enhancing our understanding of its characteristics. [ABSTRACT FROM AUTHOR]

We report the thermal excitation-induced material modification and micro/nano fabrication based on the interactions between nano laser direct writing (NLDW) and superconducting films experimentally and by simulation. The niobium (Nb) films with a critical temperature of 9 K were deposited on silicon substrate via sputtering with the thickness of around 50 nm. The boundary between material modification and micro/nano fabrication was verified by changing the interaction time and laser power continuously. Specifically, as the laser power was fixed at 250 mW and the interaction time below 440 ns, the interaction is material modification. With the increasing interaction time further, the Nb films were etched away. As the interaction time was fixed at 500 ns and the laser power below 200 mW, the interaction is material modification too. With the increasing of laser power further, the Nb films were etched away. In the experiment, the oxygen content and current–voltage characteristic (IVCs) before and after laser irradiation were displayed to verify the material modification, which is in line with the simulation results. Considering the 50 nm resolution of NLDW, in the material modification region, one could trim trilayer junctions, tune shunt resistors, or adjust critical currents, etc. In the micro/nano fabrication region, one could fabricate various devices and exploit the properties of high spatial resolution, high flexibility, and fast processing. [ABSTRACT FROM AUTHOR]

In the present work, structural, optical, and electrical properties of lithium-doped (0-6 at.%) copper oxide thin films were investigated. The films were obtained by the spray pyrolysis method on glass substrates at 450°C. The X-ray diffraction method, UV-visible spectroscopy, and the four-point probe technique were used to analyze the films. Based on the X-ray diffraction investigations, it was found that the polycrystalline films have monoclinic phases with preferred (111) and (111) crystallographic planes. The incorporation of lithium doping into the copper oxide thin film yielded crystallite sizes of approximately 2 nm. The estimated optical band gap values are decreased from 1.88 to 1.64 eV with increasing lithium concentration. Four-point probe studies revealed that the resistivity of the films decreased from 339 to 186 Kcm with increasing lithium concentration. [ABSTRACT FROM AUTHOR]

Superconducting magnets are widely used in nuclear fusion reactors, high-energy particle accelerators, steady-state high magnetic fields, etc. Higher magnetic fields and higher operating temperatures are two application trends. High temperature superconducting (HTS) materials are the only choice for high temperature and high field magnets in the future. The first- and second-generation HTS materials have a typical tape structure; their critical performance is magnetic field angle and temperature dependent. A new test facility is developed for an experimental study on the an-isotropic critical current. The field angle can be changed from 0° to 360° with a resolution of 1°. The rotation deviation angle is measured to be 0.2° when the upper part rotates 90°. The temperature can be changed from 4.2 to 80 K. The temperature errors are ±50, ±80, and ±135 mK for 4.2–20, 20–40, and 40–80 K, respectively. The angle dependence of critical current (Ic) of the tested rare-earth barium copper oxide tape within 0°–30° is strong. From 30° to 90°, the sample Ic almost does not change with the magnetic field angle. The implementation of the project will not only promote the structural optimization of HTS tapes but also promote the miniaturization and economical application of HTS magnets. [ABSTRACT FROM AUTHOR]

Copper oxide is one of the original semiconductor materials employed for solar cells in the early 19th century before Silicon solar cells became popular due to their abundant availability, and eco‐friendly nature. The optoelectronic parameters signify its huge potential in solar cell devices, though it's far from the theoretically predicted performance, provides tremendous scope to improve the solar cell performance by forming different heterojunctions. In this study, we investigated the copper oxide's (CuO) potential as an active layer in thin‐film solar cells theoretically with a new structure consisting of a Glass/ITO/Graphite/CuO/Ni. Furthermore, the charge carrier's generation rate and theoretical thresholds for photovoltaic device efficiency were determined for varying active layer thicknesses by employing a normalized light intensity equivalent to that of the AM1.5 spectrum. The optimized performance of the simulated structure by considering realistic optical parameters of the solar cell was ~24%, obtained for the 500 nm CuO films. The performed theoretical work can help to employ CuO and boost the performance of solar cells experimentally. [ABSTRACT FROM AUTHOR]

A new non-centrosymmetric silicate Ba5Y12Zn[O(SiO4)]8 (BYZSO), the first compound of the Ba–Y–Zn–Si–O system, was synthesized by a high-temperature solution method in an open system, and its structure was identified using single-crystal X-ray diffraction data. Structural analysis indicates that it crystallizes in the noncentrosymmetric space group I4¯2m (no. 121) with lattice parameters a = 18.7014(6) Å and c = 5.3640(2) Å corresponding to a tetragonal crystal system and is composed of isolated [ZnSi4O16] and [SiO4] units. Meanwhile, the effect of the cation-to-silicon ratio on the Si–O framework was also studied by investigating the structures of barium-, yttrium-, and zinc-containing silicates found in the Inorganic Crystal Structure Database (ICSD). Experimental characterization demonstrates that it possesses a short ultraviolet cut-off edge of 204 nm (6.18 eV), a moderate second harmonic generation (SHG) response (0.3× KDP) at the maximum particle size, and excellent thermal stability. Besides, first-principles theoretical calculations were carried out to elucidate the relationship between the electronic structure and optical properties. In summary, this work is instructive for the synthesis and design of silicates with different dimensions in the Ba–Y–Zn–Si–O system. [ABSTRACT FROM AUTHOR]

The composites of some transition metal oxides are currently attracting interesting roles in various fields of technology and industry. The present work attempts to tune the properties of copper oxide (CuO) for hydrogen energy generation. Iron (Fe) and cobalt (Co) were intentionally doped at precise contents into CuO thin films. X-ray diffraction (XRD) indicated that the successful substitution of Fe and Co on the Cu sites created induces pressure (tensile) stress in the lattice. Fe doping deteriorated the films' crystallinity and increased the dislocation density from 1.82 × 10−3 to 4.36 × 10−3 nm−2, while Co codoping displayed unsystematic behavior. The scanning electron microscope (SEM) images showed that the films have smooth surfaces comprising a huge number of particles/unit area with a narrow size distribution. The energy-dispersive X-ray (EDX) analysis confirmed the presence of both Fe and Co with almost the pre-calculated ratios. The optical measurement showed that increasing the Fe contents increases the absorption coefficient of CuO and narrows its optical band gap from 1.7 to 1.55 eV. The photoluminescence (PL) intensity increases for Fe-doped CuO films whereas quenched when doped with Co. A series of photoelectrochemical (PEC) measurements were conducted to evaluate the performance of the prepared films in the production of solar hydrogen. The CuO–6%Fe film showed high photocatalytic performance for H 2 generation from H 2 O splitting over a wide wavelength range of sunlight with long-term photostability. The photocurrent density of CuO–6%Fe film is about 155 times more than those obtained from pure CuO film. The incident photon-to-current efficiency (IPCE) and the solar-to-hydrogen efficiency (η STH) of CuO–6%Fe film were 5.98 % at 307 nm and 0.94 % under Xenon illumination, respectively. Hence, this work proposed an efficient and reasonable technique to enhance the performance of a CuO-based photoelectrode for solar hydrogen production. [Display omitted] • Pure, Fe-doped, and (Fe, Co) codoped CuO photoelectrodes are made by spin coating. • The structural and morphological features of photoelectrodes are studied. • The performance of the photoelectrodes for solar H 2 production is evaluated. • Fe- and (Fe, Co)- doping affect optical and electric properties. • Solar to-hydrogen conversion efficiencies are estimated, and electrode stability is addressed. [ABSTRACT FROM AUTHOR]

We demonstrate that graphite-powder-supported Cu-based fine particles, which exhibit unique electrocatalytic performance, are facilely producible at room temperature using the graphite negative electrode of a spent Li-ion battery. A majority of impurity substances containing Li, F, and P, which are the elements attributable to the solid electrolyte interphase formed on the surface of spent graphite powder, were removed by washing with water. By contrast, when the spent graphite was dispersed into a CuCl2 aqueous solution, P remained along with deposited Cu species, whereas Li and F were similarly removed. Synchrotron and microstructural analyses revealed that the fine particles deposited onto graphite powder were mainly composed of copper oxides such as Cu3(PO4)2 and CuO, which were subsequently reduced by an electrochemical treatment at room temperature, resulting in metallic Cu particles with a needle-like morphology. The thus-obtained Cu/graphite powder was found to be active toward the electrochemical synthesis of C2+ products (i.e., C2H4, C2H5OH and C3H7OH). The results also showed that such catalytically active Cu-based compounds were not formed on graphite in the case where a pristine graphite powder was used, suggesting that the use of a spent graphite negative electrode would open an environmentally benign route to the synthesis of electrocatalysts. [ABSTRACT FROM AUTHOR]

Iron chalcogenide Fe(Se,Te) films with thicknesses of 150 nm were deposited on CeO2-buffered metal tapes via pulsed laser deposition using various laser fluences. The film crystallinity and stoichiometry improved upon increasing the laser fluence. This was explained by the ablation threshold that the superconducting performance was better at higher laser fluences and was attributed to the joint contribution of higher Te contents, better texture, and strengthened in-plane strain. In addition, the pinning mechanism was studied by analyzing the in-field performance characteristics of the Fe(Se,Te) films. The dominant pinning center remained point pinning and was independent of the magnetic field direction and temperature. A collective pinning theory-based analysis showed that the vortex pinning behavior in the Fe(Se,Te) film varied from δl pinning to δTc pinning as the temperature approached the critical temperature. This was related to film superconductivity inhomogeneity, which was driven by unreacted Se and Te atoms. [ABSTRACT FROM AUTHOR]

Metal oxide solid solution thin films containing ternary mixtures of Alumina (Al 2 O 3), Chromia (Cr 2 O 3) and Cupric oxide (CuO) were successfully prepared combinatorially on FTO, quartz glass and Si substrates using radio frequency (RF) magnetron sputtering (vertical geometry; on-axis sputtering) technique with RF powers of 200 W and 100 W. XRD analysis prove the development of tetragonal phase Al 2 Cr 2 Cu 2 O 8 in sputtering target. Al 2 Cr 2 Cu 2 O 8 film deposited on Si wafer and quartz glass exhibits amorphous nature, whereas, the film deposited on FTO substrates exhibit crystalline structure with tetragonal phase owing to polycrystalline nature of the FTO substrates. Formation of high compositional purity with acceptable stoichiometric ratio of ternary metal oxide mixtures of Al 2 Cr 2 Cu 2 O 8 was ascertained from the EDX spectra. The thicknesses of Al 2 Cr 2 Cu 2 O 8 thin films are found to be in the ranges from 259 to 314 nm. Optical study showed that the optical energy band gap of Al 2 Cr 2 Cu 2 O 8 thin film deposited on quartz substrates increased to 3.84 eV from 3.78 eV with decreasing RF power from 200 W to 100 W. The spin orbital splitting (SOS) between Cr 2p 1/2 - Cr 2p 3/2 and Cu 2p 1/2 - Cu 2p 3/2 were measured to be 9.9 eV and 19.3 eV by XPS for 200 W sputtered Al 2 Cr 2 Cu 2 O 8 film on quartz substrate, which are the characteristics of Cr3+ and Cu2+ oxidation states, respectively. In addition, XPS analysis also confirms the presence of various oxygen vacancies in Al 2 Cr 2 Cu 2 O 8 thin films (as-deposited and 1000 °C annealed films) on quartz substrate with RF power of 200 W, which is the most favorable condition for the presence of room temperature ferromagnetic properties observed in the present study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Internal doping of Cu2+ at the B-site reduces the sintering temperature by 300 °C. • The Cu doping in BCZD creates oxygen vacancies, which significantly enhances the conductivity up to two-fold. • The formation of oxygen vacancies disrupts the charge balance, leading to the exsolution of Ba from the lattice. • BCZD with a 2 mol% Cu-doping demonstrates excellent stability for up to 420 h in the H 2 /3H 2 O atmosphere. • A highly stable Cu-doped BCZD electrolyte, with a low sintering temperature (1200 °C) is promising for SOFC applications. Proton-conducting electrolytes with high conductivity and long-term stability, achievable at low sintering temperatures, are of paramount importance. In this study, we investigate the impact of Cu doping on the sintering mechanism, electrical performance, and stability of BaCe 0.7 Zr 0.1 Dy 0.2-x O 3-δ (BCZD) electrolyte. The morphology, composition, structure, and chemical state of BCZD electrolytes were investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Remarkably, the sintering temperature of BCZD is reduced to 1200 °C through Cu doping Furthermore, the introduction of Cu as a dopant induces Ba exsolution from the BCZD crystal lattice alongside the generation of oxygen vacancies. XPS measurements confirmed that vacancy concentrations increase with increasing Cu doping concentrations. However, as the Cu content surpasses 2 mol%, the exsoluted Cu reacts with Ba, leading to the formation of BaCuO 2. Accumulation of BaCuO 2 at the grain boundaries adversely affects the conductivity and stability of Cu-doped BCZD, in a humidified atmosphere where it exhibits significant instability. Notably, BCZD with 2 mol% Cu content demonstrates a conductivity of 2.7 × 10-2 S cm−1 and maintains stability for up to 420 h in the H 2 /3%H 2 O atmosphere at 600 °C. In contrast, BCZD with 5 mol% Cu content exhibits a conductivity of 1.9 × 10-2 S cm−1 at 600 °C but experiences continuous degradation in a humidified atmosphere, ultimately leading to failure within 30 h. The 2 % Cu-doped BCZD exhibits high conductivity and stability at intermediate temperatures, rendering it highly suitable for solid oxide fuel cell (SOFC) applications. [ABSTRACT FROM AUTHOR]

Phase change (PC) materials, such as metal oxides, possess high fundamental and applied importance for modern memory, sensor, and photonic devices. However, revealing the kinetics and mechanisms of PC and achieving the reversible and irreversible PC regimes are still a challenge. Here, we report on 200 nm films of metastable Cu4O3 obtained by magnetron sputtering. In situ structural and optical analyses during air annealing revealed the thermal induced PC from Cu4O3 to CuO. Combination of x-ray diffraction and optical transmittance with heating up to 450 °C allowed us to explore the PC rate and then to correlate it with classical nucleation and crystal growth mechanism. We have also revealed two regimes of PC, possessing reversible 12% (1.42–1.25 eV) and irreversible 220% (1.25–2.75 eV) direct bandgap tuning by temperature. The results, thereby, pave the way for controllable transformation of copper oxide thin films to achieve the desired microstructure and its functionality. [ABSTRACT FROM AUTHOR]

A simple one-pot approach for the synthesis of gold-loaded copper oxide (Au–CuOx) nanoplates was employed to develop a sensitive electrochemical surface enhanced Raman scattering (EC-SERS) substrate for the detection of anti-cancer drug hydroxycarbamide (HC). HC has been used for decades as a therapeutic agent against sickle cell anaemia and various cancers. The Au–CuOx substrate was characterized using various spectroscopic and imaging techniques, including XRD, XPS, FTIR, TEM and SEM. The electrochemical impact on the SERS-based sensing capability was investigated by immobilizing the bimetallic material on a conductive glass support acting as a working electrode. First-principle calculations were carried out to predict the electrostatic properties, electron transfer contribution and adsorption energetics of HC molecules on the nanostructured surface. Spectroscopic and theoretical investigations suggested that Au-loaded copper oxide exhibits inherent surface plasmon resonance (SPR) properties that can be notably enhanced by incorporating the electrochemical factor. Several prominent Raman peaks associated with HC and ascribed by the NCN bending, CN stretching, NO stretching, CO stretching, and NH2 wagging vibrational modes showed substantial enhancements upon the electrochemically induced interaction between the SERS substrate and the drug molecules. A limit of detection of one-tenth of nanomolar concentration could be achieved under optimum conditions. The presented methodology could be potential in the context of biomedical laboratories for the sake of quick and reliable assessment. [ABSTRACT FROM AUTHOR]

In this paper, we present modelling of spectroscopic ellipsometry data. The measured samples are thin films of copper oxides modified with the ion implantation method. The samples were prepared using reactive magnetron sputtering. Thin films of CuO and Cu4O3 were deposited and subjected to Cr ion implantation with an energy of 15 keV and a dose of 5 × 1016 ions/cm2. The decrease in crystallinity of the thin film as a result of the implantation was inspected with X-ray diffraction measurements. The implantation of Cr+ ions was simulated using the Stopping and Range of Ions in Matter software by Ziegler and Biersack. Ion beam energy of 15 keV was simulated to estimate the distribution of Cr ions in the copper oxides thin films. Optical parameters, such as refractive index, extinction coefficient, and absorption coefficient of the thin films, were investigated with spectroscopic ellipsometry. Multilayered models based on Tauc–Lorentz oscillators were developed for both oxides. Analysis of the optical properties showed that the ion implantation with Cr decreased the absorption of copper oxides thin films and the modelling proved that the material properties of top layers changed the most. [ABSTRACT FROM AUTHOR]

A self-powered photodetector based on copper oxide thin film (Cu2O-TF) is deposited using the e-beam evaporation technique. One notable advantage of this fabrication process is that it does not require the use of any catalysts. The XRD analysis revealed the presence of cuprous oxide (Cu2O) with a distinct peak at ~ 42.66º indicating (200) orientation. SEM analysis confirms the successful growth of the Cu2O-TF, revealing a porous semi-spherical structure with a measured thickness of ~ 100 nm. Moreover, electrical analysis was studied for the voltage range of − 2 to 2 V. The Cu2O-TF device exhibited a rectification ratio (RR) of 64 at + 1 V. Notably, the device exhibited self-powered characteristics, showing a stable switching response characterized by rise time (τr) values of ~ 0.183 sec and fall time (τf) of ~ 0.236 s at 0 V. Furthermore, the device obtained maximum responsivity in the near IR region, extending from ~ 700 to 800 nm, with peak intensity reaching ~ 720 nm along with responsivity values of ~ 6.6 mA/W. Moreover, the device obtained a detectivity value of ~ 3.45 × 1011 Jones and a low-noise equivalent power of ~ 8.12 × 10–12 at 0 V. The overall results highlight the suitability of the device for self-powered photodetector applications. [ABSTRACT FROM AUTHOR]

Copper oxide thin films were grown on (111)-oriented MgO substrates via the DC magnetron sputtering technique. High-purity copper was used as target material. The films were grown in an atmosphere of pure argon at a pressure of 1.27 torr. The substrate temperature was maintained at 400 °C during the growth. After deposition, the films were annealed in-situ in an argon/oxygen atmosphere (80%/20%) at 450 °C for either two or four minutes. It was found that the annealing time was a sensitive process parameter for achieving single- or mixed-phase copper oxide thin films. The single-phase cuprous (Cu2O) oxide films were obtained with the shorter annealing time (two minutes). Longer annealing times led to destabilization of the Cu2O phase, concomitant with the formation of the cupric oxide (CuO) phase in the sample. From optical spectroscopy studies, a band gap value of 2.4 eV was determined for the Cu2O films. This value decreased for the mixed-phase films. Near-infrared spectroscopy spectra were characterized by the presence of troughs and peaks, probably stemming from volume and surface scattering. Furthermore, differences in the intensity of the absorption with the chosen annealing process were observed, which were probably associated with slight variations in the grain size and/or morphology of the films. The electrical behavior of the films was investigated by means of complex impedance spectroscopy and DC transport measurements. Strong dependence of the electrical properties on the frequency and temperature was observed. The impedance spectra were well modeled in terms of equivalent electrical circuits. As a result, it was found that the predominant contribution to the resistance and capacitance of the Cu2O films came from the bulk of the grains. It was also verified that the relaxation of the charge carriers was a thermally active process with an activation energy of ~ 0.17 eV. A semiconducting-like behavior in the 100–320 K temperature range was also verified. The electronic transport mechanism in the Cu2O films was satisfactorily described within the framework of the Mott variable range hopping model. From the fit of this model to the experimental data, values as high as 3.5 × 1018 eV−1 cm−3 and ~ 12 nm were estimated for the density of states at the Fermi level and the hopping distance, respectively. [ABSTRACT FROM AUTHOR]

Highly transparent resistive-switching (RS) devices were fabricated by growing amorphous tantalum pentoxide (a-Ta2O5) and indium tin oxide (a-ITO) thin films on barium-borosilicate glass (7059) substrates, using electron beam evaporation. These layers exhibited the transmittance greater than ~ 85% in the full visible region and showed RS behavior and battery-like IV characteristics. The overall characteristics of RS can be tuned using the top electrode and the thickness of a-Ta2O5. Thinner films showed a conventional RS behavior, while thicker films with metal electrodes showed a battery-like characteristic, which could be explained by additional redox reactions and non-Faradaic capacitive effects. Devices having battery-like IV characteristics showed higher enhanced, retention and low-operation current. [ABSTRACT FROM AUTHOR]

Miniaturization and electrochemical performance enhancement of electrodes and microelectrode arrays in emerging long-term implantable neural stimulation devices improves specificity, functionality, and performance of these devices. However, surgical site and post-implantation infections are amongst the most devastating complications after surgical procedures and implantations. Additionally, with the increased use of antibiotics, the threat of antibiotic resistance is significant and is increasingly being recognized as a global problem. Therefore, the need for alternative strategies to eliminate post-implantation infections and reduce antibiotic use has led to the development of medical devices with antibacterial properties. In this work, we report on the development of electrochemically active antibacterial platinum-iridium electrodes targeted for use in neural stimulation and sensing applications. A two-step development process was used. Electrodes were first restructured using femtosecond laser hierarchical surface restructuring. In the second step of the process, atomic layer deposition was utilized to deposit conformal antibacterial copper oxide thin films on the hierarchical surface structure of the electrodes to impart antibacterial properties to the electrodes with minimal impact on electrochemical performance of the electrodes. Morphological, compositional, and structural properties of the electrodes were studied using multiple modalities of microscopy and spectroscopy. Antibacterial properties of the electrodes were also studied, particularly, the killing effect of the hierarchically restructured antibacterial electrodes on Escherichia coli and Staphylococcus aureus—two common types of bacteria responsible for implant infections. [ABSTRACT FROM AUTHOR]

In this report, the morphological, optical, electrical, and photovoltaic properties of copper oxide and calcium-doped copper oxide thin films produced via the spray coating method were studied. The thermal post treatment at 300 °C in an inert atmosphere allowed us to obtain a single phase of Cu2O with 21 Ωcm of resistivity (ρ). In this study, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and 10 wt% Ca admixtures with copper oxide were investigated. The determined optimal calcium dopant concentration was 4 wt%. XRD analysis was used to reveal the chemical composition of the produced layers. It was found that a calcium dopant does not change the layer composition but improves its electrical parameters. Based on UV-Vis spectra, the band gap energy and Urbach energy were calculated. The morphology of produced thin films was described as smooth and nanocrystalline, corresponding to a grain size calculated based on the Scherrer equation. Finally, it was shown that the developed protocol of low-resistivity copper oxide deposition via the spray coating technique can be successfully implemented in heterojunction solar cell production. The I–V parameters of Ag/n-type CzSi/REF:CuOx and 4Ca:CuOx/Carbon were collected, and the achieved efficiency was 2.38%. [ABSTRACT FROM AUTHOR]

Yttrium-doped barium cerate (BCY) is one of the best proton-conducting ceramics to be used in fuel cells/electrolyzers at intermediate temperatures, due to its high hydration enthalpy and high conductivity. Nonetheless, it has commonly been discarded for these applications due to its instability in the presence of carbonaceous and humidified atmospheres. A recent work has addressed this issue, by suggesting the use of this material in very low water vapor partial pressures (p H2O ∼ 10−4 atm) [ Electrochimica Acta 334 (2020) 135625 ] and at low temperatures (T ≤ 400 °C). Under these conditions, BCY can still offer pure protonic conductivity while also offering suitable stability. In the current work, we provide a comprehensive analysis of the effects of the acceptor dopant concentration (Y 2 O 3) in the structural, microstructural, and electrical properties in a wide compositional series of BaCe 1- x Y x O 3- δ (x = 0.05, 0.10, 0.20 and 0.30) at low levels of humidity in the low temperature range (100–400 °C). The results show that BaCe 0.9 Y 0.1 O 3- δ (BCY10) offers the highest bulk conductivity in these conditions, while further increase in dopant concentration leads to impairment due to " proton trapping " effects. In contrast, the specific grain boundary conductivity increases with increasing dopant concentration due to a reduction of Schottky barrier height at the space-charge layer. We demonstrate that, by operating at very low temperatures (e.g. , below 400 °C), the peak performing, BCY10 material can still operate at very low levels of water vapor partial pressure (p H2O ∼ 10−4 atm), where its stability can be maintained. This work paves the way for the optimization of this material, with a focus on utilizing low humidity levels and low temperatures, where it can offer a competitive advantage over that of the majority of other proton-conducting perovskites for potential applications operating under these conditions. [ABSTRACT FROM AUTHOR]

The conversion of copper oxide films on copper to copper sulfide has been investigated in sulfide‐containing chloride solutions. Single‐phase Cu2O films and duplex films consisting of Cu2O and CuO, and possibly Cu(OH)2, were prepared electrochemically on copper specimens at various applied potentials and characterized using Raman spectroscopy, scanning electron microscopy, and energy dispersive X‐ray analyses. The surface condition of the specimens subsequently exposed to a solution containing sulfide was monitored by measuring the corrosion potential (Ecorr) for various exposure periods, then cathodic stripping voltammetry was performed. Cuprite (Cu2O) was observed to be converted to Cu2S by chemical reaction with sulfide, while the conversion mechanism for the mixed deposit could comprise a galvanic process involving CuII reduction coupled to the formation of Cu2S by the reaction of sulfide with copper within pores in the Cu2O/CuO surface film and a chemical conversion of Cu2O to Cu2S. Cupric hydroxide was not converted to Cu2S on the time scale (24 h) of these experiments. [ABSTRACT FROM AUTHOR]

In this work, copper oxide thin films were deposited by pneumatic spray pyrolysis method on a microscopy glass substrate, heated at 400°C for different deposition times (5min, 10min, 15min, 20min, 25min, and 30min) using a 0.1M of precursor concentration. These films are characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), spectroscopic ellipsometry, UV-visible spectroscopy, four points method, and water contact angle. According to the XRD, all peaks confirm the formation of the phase tenorite of the monoclinic structure. The deposited were polycrystalline copper oxide CuO with directions along (111) plane, the crystallites size between 14 and 23 nm. FTIR spectroscopy confirms the presence of the CuO phase and agrees that it will result in XRD. From the transmission spectra, the average transmission between 400 and 800nm is 65% to 50%, and the gap energy is 2.65 eV to 1.09 eV. The water contact angle values in all samples are greater than 90° and range from 96.4° to 103.2°, as we can see from these results that all the samples are hydrophobic films. [ABSTRACT FROM AUTHOR]

In this work, we study the electromagnetic bandgaps and passbands of some fixed-length Thue-Morse plasma/dielectric/superconductor photonic band multilayers. we consider vanadium (V) as a low-temperature superconductor and investigate the effect of the refractive index of the dielectric, the length of the photonic crystal length, the number of layers, plasma density, and the temperature of the superconductor on the transmission spectrum of the photonic crystal. In the second part, we consider copper oxide calcium barium mercury (H g B a 2 C a 2 C u 3 O 10) as a high-temperature superconductor, and similar to the first part, we examine the effect of the mentioned factors on the transmission spectrum. Finally, we investigate the high and low-temperature superconductivities by comparing and examining the above-mentioned parameters for these structures in a fixed-length configuration. [ABSTRACT FROM AUTHOR]

Arc duration and erosion characteristics of cables are closely related to electrical fire hazards. In this study, the arc duration and arc erosion characteristics of copper and aluminum core cables were explored. The main erosion modes of copper core cable with mica insulation (HC0) and aluminum core cable with polyimide (PI) insulation (HA0) were determined. Results show that several large molten droplets with diameters of 5 ± 0.5 mm would drip down from the molten pool on the cable end during arcing of HC0, but the molten droplets are adhered to the molten pool and do not drip down during arcing of HA0. We concluded that the differences in melting energy and oxide film between copper and aluminum are the main reasons for this phenomenon. Besides, the molten pool can be formed on the cable end as the insulation is heatproof, which plays a vital role in prolonging the arc duration of cables. The arc duration of cables with heatproof insulation is longer than those with common insulation. This means that the cables with heatproof insulation have higher fire hazards from the perspective of arc duration. To further understand the influence of molten pools on arc duration, an arc duration model was developed based on energy balance, which is beneficial in determining the arc duration of cables with heatproof insulation in electrical fire accident investigation. [ABSTRACT FROM AUTHOR]

The integration of high-temperature superconducting YBa2Cu3O6+x (YBCO) into flexible electronic devices has the potential to revolutionize the technology industry. The effective preparation of high-quality flexible YBCO films therefore plays a key role in this development. We present a novel approach for transferring water-sensitive YBCO films onto flexible substrates without any buffer layer. Freestanding YBCO film on a polydimethylsiloxane substrate is extracted by etching the Sr3Al2O6 sacrificial layer from the LaAlO3 substrate. In addition to the obtained freestanding YBCO thin film having a Tc of 89.1 K, the freestanding YBCO thin films under inward and outward bending conditions have Tc of 89.6 and 88.9 K, respectively. A comprehensive characterization involving multiple experimental techniques, including high-resolution transmission electron microscopy, scanning electron microscopy, Raman, and x-ray absorption spectroscopy, is conducted to investigate the morphology, structural, and electronic properties of the YBCO film before and after the extraction process where it shows the preservation of the structural and superconductive properties of the freestanding YBCO virtually in its pristine state. Further investigation reveals the formation of a YBCO passivated layer serves as a protective layer that effectively preserves the inner section of the freestanding YBCO during the etching process. This work plays a key role in actualizing the fabrication of flexible oxide thin films and opens up new possibilities for a diverse range of device applications involving thin-films and low-dimensional materials. [ABSTRACT FROM AUTHOR]

Highly transparent resistive-switching (RS) devices were fabricated by growing amorphous tantalum pentoxide (a-Ta2O5) and indium tin oxide (a-ITO) thin films on barium-borosilicate glass (7059) substrates, using electron beam evaporation. These layers exhibited the transmittance greater than ~ 85% in the full visible region and showed RS behavior and battery-like IV characteristics. The overall characteristics of RS can be tuned using the top electrode and the thickness of a-Ta2O5. Thinner films showed a conventional RS behavior, while thicker films with metal electrodes showed a battery-like characteristic, which could be explained by additional redox reactions and non-Faradaic capacitive effects. Devices having battery-like IV characteristics showed higher enhanced, retention and low-operation current. [ABSTRACT FROM AUTHOR]

The article focuses on the synthesis of superconducting Nd1−xEuxNiO2 thin films using an in situ reduction process. It mentions by incorporating Eu as a dopant in the NdNiO2 compound, the authors achieved a superconducting phase with a maximal onset critical temperature of 21 K. It study highlights the potential of Eu doping and compares the properties of Nd1−xEuxNiO2 to alkaline earth-doped counterparts, providing insights into the role of 4f electrons in superconducting nickelates.

In this paper, we develop fabrication technology and study aluminum films intended for superconducting quantum nanoelectronics using AFM, SEM, XRD, HRXRR. Two-temperature-step quasiepitaxial growth of Al on (111) Si substrate provides a preferentially (111)-oriented Al polycrystalline film and reduces outgrowth bumps, peak-to-peak roughness from 70 to 10 nm, and texture coefficient from 3.5 to 1.7, while increasing hardness from 5.4 to 16 GPa. Future progress in superconducting current density, stray capacitance, relaxation time, and noise requires a reduction in structural defect density and surface imperfections, which can be achieved by improving film quality using such quasiepitaxial growth techniques. [ABSTRACT FROM AUTHOR]

The magnesium doped yttrium barium zirconate, YBa2Zr3 –xMgxO9.5 – δ (0 ≤ x ≤ 0.5) has been prepared by the standard solid-state reaction method and the room temperature X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), particle size analysis (PSA) and thermogravimetric analysis (TGA) have been investigated for phase purity, structural and thermal characterizations. The XRD data of the materials have been indexed with the winXpow software and Rietveld refinements have been done by FullProf suite programarend is found to be double phase of cubic perovskite and a small amount of cubic fluorite. The microstructural parameters such as size, stress, strain, crystal energy are obtained from XRD line broadening data using different models and found that the cubic perovskite phase contributed a large part to the solid solution shows a larger crystallite size of ~212 nm (±13 nm) than its fluorite counterpart which is found to be ~132 nm (±1 nm). The TEM analyses confirm the presence of both phases. The TGA scans in nitrogen environment exhibits stability up to 1000°C. The sizes of the particles from 9 to 13 μm. Scanning electron microscope images reveals that the materials sintered at 1450°C are porous. [ABSTRACT FROM AUTHOR]

In this work, we have developed thin layers of CuO by method of pyrolysis spray. The samples developed are obtained from the use of copper chloride precursor CuCl2 with molarity of 0.1 mol/l and a spray number that varies between 25 to 150 spray with a step of 25 spray to see the effect of this parameter on the structural, optical and electrical properties of our material. The structural characterization of the obtained thin layers was done by X-ray diffraction (XDR) and spectroscopy Raman. The optical characterization was done by UV visible spectroscopy and electrical characterization by four points. The XDR has confirmed the crystalline state of our thin layers and the formation of the CuO with a preferential direction according to the plan (002). The Raman spectroscopy allowed us to confirm the presence of a thin layer based on the CuO. The lattice parameters remain mainly constant. The spectra UV visible of films has given a transmission varies between 80% and 40% in visible. The optical gap determined varies between 1.75 eV and 1.2 eV. Electrical characterization shows that the resistivity varied between 3.21KΩ.cm and 1.7KΩ.cm depending on number of spray for ethanol gas sensing applications. [ABSTRACT FROM AUTHOR]

Shelf life increasing of red meat has the great importance due to its perishable properties and consumers' demand to use food free synthetic preservatives. This study was aimed to investigate the antimicrobial and antioxidant effects of poly lactic acid film (PLA) containing different concentrations of ethanolic sumac extract (SE 1 and 3%) and copper oxide nanoparticles (CuO1 and 2%) on shelf life enhancement of the minced beef during cold storage. The samples were stored at 4 ± 1 °C for 12 days and analyzed at 0, 1, 3, 6, 9 and 12 days of the storage period. All of the treatments significantly (P≤0.05) decreased total viable count, psychrotrophic bacteria and Enterobacteriaceae spp. population as compared control group during the storage period. Total volatile basic nitrogen (TVB -N) and pH values of the non -packed samples (control) were significantly (P≤0.05) higher than the packed ones during the storage time. The combined treatments containing SE and CuO -NPs showed the highest efficiency in shelf life increasing of the cold stored minced beef in dose dependent manner. Based on the results, it can be concluded that the usage of biodegradable poly lactic acid film containing a complex of SE and CuO -NPs is effective packaging in the shelf life improvement of minced beef during 12 days of the refrigerated storage period. [ABSTRACT FROM AUTHOR]

We investigated the hole mobility limiting factors in dopant-free p-type distributed polarization-doped (DPD) AlGaN layers by an experimental method. p-DPD AlGaN exhibited a higher hole mobility than GaN:Mg with a similar room temperature hole concentration across all temperature ranges owing to the absence of ionized impurity scattering. In addition, unlike in n-DPD AlGaN, alloy scattering was not always critical in p-DPD AlGaN. The extracted alloy scattering potential was only 0.3 eV, which resulted in a reduced effect of alloy scattering and originated from a small valence band offset in the GaN/AlN heterojunction system. The results suggest that DPD principally enables the fabrication of low-resistance p-type nitride semiconductor thin films as a result of the high hole concentration and high hole mobility. [ABSTRACT FROM AUTHOR]

• Electronic recycling exposes workers to toxic metals, e.g. lead, cadmium and nickel. • Metals and dust concentrations are associated with the volume of materials treated. • Dismantling of cathode ray tubes generates more lead and yttrium than other devices. • Exposures to metal mixtures increase risk of renal and nervous system disorders. • Occupational health & safety practices are inadequate in most facilities. Electronic waste recycling (e-recycling) involves manual operations that expose workers to toxic metals. We aim to describe occupational health and safety practices and workers' exposures to metals in the Canadian formal e-recycling industry, and to estimate the health risk associated with multiple exposures. This cross-sectional study documented practices through observations and questionnaires, and assessed metal exposures using personal air samples and biomarkers. Health risks were estimated relative to recognised occupational exposure guidelines, and using an additive approach for consideration of multiple exposures. Six e-recycling and one commercial recycling facilities were investigated, and the metal exposures of 99 workers (23 women) were measured. In most facilities, dust control was inadequate and personal protective equipment was improperly worn. In e-recycling, lead was detected in all air samples and in most blood samples, up to 48 µg/m3 and 136 µg/l, respectively. Other quantified metals included beryllium, mercury, arsenic, barium, cadmium, chrome, cobalt, copper, indium, manganese, nickel and yttrium. When handling cathode ray tube screens, workers were 4.9 times and 8.5 times more likely to be exposed to lead and yttrium, respectively, than workers who were not assigned to a specific type of electronics. Overall, exposures were largely associated with facility size and airborne dust concentration. The additive hazard indices for airborne exposures raised concerns for kidney disorders, for peripheral and central nervous systems, and for the male reproductive system. Minimizing airborne dust through collective control methods and adequately using personal protection should reduce metal exposures and associated health risks in this growing industry. [ABSTRACT FROM AUTHOR]

Yttrium-doped barium cerate (BCY15) was used as ceramic matrix to obtain Ni/BCY15 anode cermet for application in proton-conducting solid oxide fuel cells (pSOFC). Ni/BCY15 cermets were prepared in two different types of medium, namely deionized water (W) and anhydrous ethylene glycol (EG) using wet chemical synthesis by hydrazine. An in-depth analysis of anodic nickel catalyst was made aiming to elucidate the effect of anode tablets' preparation by high temperature treatment on the resistance of metallic Ni in Ni/BCY15-W and Ni/BCY15-EG anode catalysts. On purpose reoxidation upon high-temperature treatment (1100 °C for 1 h) in air ambience was accomplished. Detailed characterization of reoxidized Ni/BCY15-W-1100 and Ni/BCY15-EG-1100 anode catalysts by means of surface and bulk analysis was performed. XPS, HRTEM, TPR, and impedance spectroscopy measurements experimentally confirmed the presence of residual metallic Ni in the anode catalyst prepared in ethylene glycol medium. These findings were evidence of strong metal Ni network resistance to oxidation in anodic Ni/BCY15-EG. Enhanced resistance of the metal Ni phase contributed to a new microstructure of the Ni/BCY15-EG-1100 anode cermet getting more stable to changes that cause degradation during operation. [ABSTRACT FROM AUTHOR]

The paper presents the study results of barium-neodymium ferroniobate films with a thickness of 180 and 980 nm obtained by RF cathode sputtering. Using X-ray diffraction and magnetic force microscopy, we found that the films are single-phase, epitaxial and do not contain magnetic impurities. Atomic force microscopy data show that the films grow according to the Volmer-Weber mechanism. [ABSTRACT FROM AUTHOR]

The major challenges in producing highly electrically conductive copper films are the oxide content and the porosity of the sintered films. This study developed a multilayer sintering method to remove the copper oxides and reduce copper film porosity. We used a self-built arc discharge reactor to produce copper nanoparticles. Copper nanoparticles produced by arc discharge synthesis have many advantages, such as low cost and a high production rate. Conductive inks were prepared from copper nanoparticles to obtain thin copper films on glass substrates. As demonstrated by scanning electron microscopy analyses and electrical resistivity measurements, the copper film porosity and electrical resistivity cannot be significantly reduced by prolonged sintering time or increasing single film thickness. Instead, by applying the multilayer sintering method, where the coating and sintering process was repeated up to four times in this study, the porosity of copper films could be effectively reduced from 33.6% after one-layer sintering to 3.7% after four-layer sintering. Copper films with an electrical resistivity of 3.49 ± 0.35 μ Ω·cm (two times of the bulk copper) have been achieved after four-layer sintering, while one-layer sintered copper films were measured to possess resistivity of 11.17 ± 2.17 μ Ω·cm. [ABSTRACT FROM AUTHOR]

The transition metal oxide-based nanomaterial attracted researchers for its various applications due to its interesting physical, chemical, and optical properties. Copper oxide thin films with different oxidation states were prepared on various transparent, nontransparent nature conducting substrates from the acidic and alkaline medium by electrodeposition technique. The deposition parameters such as potential, bath temperature, solution pH, and deposition time determine the physical, chemical, and optical properties. The complexing agents such as sodium thiosulfate, lactic acid, citric acid, and triethanolamine determine the stability of cuprous and cupric ions in the deposited films. Optical properties reported that the deposited films have direct band gap value 1.3 and 3.7 eV represents the absorbance of the deposited films in the visible region of solar spectrum. The absorbance of light in visible region, good electrical conductivity, and various nanostructure morphologies with the environment-friendly constituents are the distinctive properties of copper metal oxides. [ABSTRACT FROM AUTHOR]

In this paper, we report the kinetics, nucleation, and growth mechanism of copper oxide electrodeposited on ITO from copper sulfate and lactic acid solutions at different pH values, using cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). According to the cyclic voltammetry, the cathodic peak potential increases with increasing scan rate, indicating that the deposition of Cu2O is an irreversible process influenced by diffusion control. To further investigate the type of Cu2O nucleation, it was found that Cu2O followed diffusion-controlled three-dimensional transient nucleation by comparing the timing current curves with the Scharifker-Hills three-dimensional nucleation model. Furthermore, the three-dimensional transient nucleation was still followed regardless of the deposition potential and pH variation; this result was also confirmed from field emission scanning electron microscopy (FE-SEM). According to the EIS profile, the charge transfer resistance of Cu2O decreased with the increase in deposition potential; the charge transfer resistance was the smallest at pH = 9. In the timing current curve D (diffusion coefficient) showed a decreasing trend with increasing pH values. The nucleation pattern and growth process of nuclei at the early stage of electrodeposition are the basis for the formation of thin films, which is a guideline for obtaining films with better performance. [ABSTRACT FROM AUTHOR]

Copper nano/microparticles were synthesized in octadecene at 290 °C by thermal decomposition method. Copper acetate monohydrate, stearic acid, and 1-octadecanol were used as copper precursor, capping and mild reducing agents, respectively, at the synthesis. Borosilicate glass substrates submerged into the reaction solution during the synthesis were coated by copper nano/microparticles. Thermal decomposition and coating techniques were combined in this study. Copper nano/microparticles were thoroughly characterised via X-ray powder diffraction, X-ray photoelectron, Raman, and attenuated total reflectance-Fourier transform infrared spectroscopies, and scanning and transmission electron microscopies. The average minimum Feret's diameter of these synthesized copper particles was measured as ~87 ± 19 nm. Copper nano/microparticles were converted to copper oxide nano/microparticles by applying heat treatment at 250 °C. The phase composition of copper oxide nano/microparticles was determined by reference intensity ratio analysis. The energy gap of copper oxide nano/microparticles was determined as ~2.33 eV by using Tauc's method. Their band gap PL emission was observed at ~2.15 eV. [ABSTRACT FROM AUTHOR]