Search Results (151)

AlSb film has attracted attention for its excellent properties, and many preparation methods have been explored. Herein, AlSb thin films were prepared by the DC magnetron co-sputtering method, and the interfacial behavior between the films and air molecules was investigated by X-ray diffraction (XRD), Auger electron spectroscopy (AES) testing, and density functional theory (DFT) calculations to elucidate the deliquescence process of AlSb thin films and its underlying mechanism. The results revealed that AlSb thin films exhibited Sb₂O₄ and Sb₂O₅ phases, while the thin films doped Cu no longer showed any Sb oxide phases after the film was exposed to air for one day. The chemical state of aluminum in the film remained stable along the depth direction, whereas antimony exhibited a pronounced gradient in chemical state from the surface to the interior. The oxidation state of Sb ions varied from −3 in the interior to +5 at the surface. The interaction between the (111) crystal plane of the AlSb film and air molecules is an exothermic process, with water molecules exhibiting the highest adsorption energy on the film surface, followed by oxygen molecules. The adsorption energies for nitrogen and carbon dioxide molecules were the lowest. Consequently, AlSb molecules readily combine with H₂O molecules. Furthermore, doping the AlSb film with copper or zinc atoms effectively reduced the adsorption energy for water and oxygen molecules, offering a new approach to suppress the deliquescence and oxidation of AlSb thin films. This study provides an important theoretical foundation for subsequent research on this material system. Full article

Copper and its alloys are indispensable for electronics, communications, new energy systems, and aerospace engineering due to their exceptional electrical conductivity and mechanical properties. However, the thin cuprous oxide (Cu₂O) layer that naturally forms on copper and its alloys is prone to failure under elevated temperatures and high humidity, particularly in chloride-rich environments, leading to accelerated localized corrosion. While conventional chromate-based passivation has long been the industrial standard for preventing corrosion, its use has been increasingly restricted by global regulations (such as RoHS and REACH) due to its severe toxicity and health risks. To address the conflict between environmental compliance and protective performance, this review systematically evaluates recent advances in environmentally friendly, chromium-free anti-corrosion coatings in the present review. These alternative coatings are critically analyzed and categorized into four mechanistic groups: (i) inorganic conversion coatings (including molybdate, tungstate, rare earth, and phosphate systems); (ii) organic films formed via chemical or physical adsorption (such as organic inhibitors, thiol-based monolayers, and organosilane self-assembled films); (iii) conversion coatings engineered through covalent bonding, coordination chemistry, and microstructural tailoring; and (iv) multifunctional coatings that integrate self-healing capability with high electrical conductivity. Beyond providing a technical summary, this review explored how the swift progression of electronic information technology, new energy infrastructure, and robotics has imposed more exacting, multifunctional demands on copper components. This review provides a strategic roadmap for future research and prioritizes the creation of protection strategies that operate robustly in multi-physics coupling environments—integrating high conductivity, autonomous self-healing, and long-term chemical stability to ensure the reliability of next-generation infrastructure. Full article

Copper oxide (CuO) has emerged as a promising p-type semiconductor for a wide range of applications, including gas sensing and photoelectric devices. This is due to its narrow band gap, high chemical stability and low cost. In recent years, increasing attention has been paid to the development of high-quality CuO thin films with precisely controlled structural and electronic properties. Among various fabrication techniques, atomic layer deposition (ALD) provides unique advantages like excellent thickness control, conformality and tunability of film composition at the atomic scale. This review provides a comprehensive overview of CuO thin films with a particular focus on ALD-based fabrication approaches. First, conventional deposition methods are briefly discussed. Next, the fundamentals of ALD processes for CuO growth are presented including precursor chemistry, reaction mechanisms and the influence of key process parameters. Special attention is given to the correlation between deposition conditions and the resulting structural, optical and electrical properties of the films. Subsequently, the impact of these properties on device performance is analyzed in the context of gas sensing and photoelectric applications. Finally, current challenges and future perspectives are outlined, emphasizing the need for improved control over phase composition, defect engineering, and integration with nanostructured systems. Full article

Copper oxide (CuO) is a narrow-bandgap p-type semiconductor promising for visible-light photocatalysis, yet it suffers from rapid charge recombination and low carrier transfer efficiency. In this study, two distinct CuO photocatalysts were fabricated via different routes: two-dimensional CuO nanosheets derived from annealing a CuBDC metal–organic framework (MOF) precursor, and oriented one-dimensional CuO nanoflower arrays prepared by electrochemical deposition, followed by annealing. The crystal structure, morphology, optical absorption, and photoelectrochemical properties were systematically characterized by XRD, SEM, XPS, UV-Vis spectroscopy, transient photocurrent response, EIS, and PL spectroscopy. The CuO nanoflower thin film exhibits a broad visible-light absorption, a markedly higher photocurrent density (42.25 μA cm⁻²), and lower charge-transfer resistance compared to CuO nanosheets. When evaluated for visible-light photocatalytic degradation of methylene blue (MB), rhodamine B (RhB), and malachite green (MG), the CuO thin film completely degraded MB within 15 min, with an apparent rate constant of 20.15 h⁻¹—approximately three times that of CuO nanosheets. It also showed 1.2- and 1.28-fold higher activity for RhB and MG, respectively. The enhanced performance is attributed to the oriented nanoflower architecture that provides continuous charge transport pathways, suppresses carrier recombination, and extends light propagation via multiple reflections. This work demonstrates that microstructural engineering is an effective strategy to overcome the intrinsic limitations of CuO photocatalysts for wastewater treatment. Full article

Copper (Cu) thin films and meshes on polyethylene terephthalate (PET) substrates are promising flexible transparent conductive electrodes (TCEs), yet their practical use is limited by insufficient interfacial adhesion and poor oxidative stability on inert polymer substrates. This work addresses these issues via a synergistic strategy of interfacial layer engineering and maskless laser lithography-based aperiodic mesh patterning, systematically comparing ceramic (Al₂O₃) and metallic (NiCr) interfacial layers for PET-supported Cu films and fabricating Linear/Sinusoidal aperiodic Cu meshes with tailored performance. Magnetron sputtering shows that Ar plasma-activated NiCr interfacial layers form a gradient-alloyed interface with Cu via interdiffusion, achieving 5B-level adhesion, mitigating bending-induced stress concentration, and enhancing damp-heat resistance (85 °C/85% RH) by suppressing oxidation—outperforming brittle Al₂O₃ layers. Patterning the optimized Cu/NiCr/PET structure into micrometer-scale meshes yields a Linear design with superior optoelectronic performance (~10.8 Ω/sq sheet resistance, >87% transmittance at 550 nm) and a Sinusoidal design with enhanced bending robustness via stress delocalization. Microstructural and elemental analyses clarify the NiCr layer’s interfacial toughening and anti-oxidation mechanisms. Practical validation in flexible transparent heaters demonstrates rapid thermal response and >20 h continuous operational stability. This study provides a scalable design strategy for high-performance PET-supported Cu meshes, offering insights for interface and structural optimization of flexible metallic TCEs for next-generation optoelectronics. Full article

The study of wide-bandgap nanomaterials has gained considerable attention in recent years, especially in the case of semiconductor oxides that exhibit full or partial optical transparency in fundamental research and technological applications. These include optoelectronic devices, gas sensors and photovoltaic cells, among others. The activation or adjustment of optical and structural properties, especially the bandgap and the parameters of unit cell lattice, can be achieved by varying the dopant concentration during the synthesis of semiconductor thin films in these applications. In this context, copper oxide has emerged as a valuable material, owing to its thoroughly analyzed structural behavior and its broad potential across multiple technological fields. The present work focuses on the synthesis of zinc-doped copper oxide (Zn_xCu_1−xO) thin films on silicon and quartz substrates through ultrasonic spray pyrolysis. The effects of varying the zinc doping concentration (0.0, 5.0, 10.0 and 20.0 at. %) on the morphological, structural, and optical characteristics of the Zn_xCu_1−xO films were analyzed. Scanning electron microscopy (SEM) analysis indicated a gradual increase in nanoparticle size, rising from 221 nm for CuO to approximately 322 nm for the Zn_0.2Cu_0.8O samples as the zinc content increased. Structural characterization via X-ray diffraction (XRD) confirmed a monoclinic crystal arrangement belonging to the $C_{2h}^6$ (c2/c) space group. As the percentage of zinc increased, the XRD peaks shifted to lower angles, consequently increasing the volume and crystal lattice parameters of the Zn_xCu_1−xO structure; this finding was additionally supported by a redshift observed in the Raman analysis. The transmittance spectra of the films showed low transmittance between 40 and 44%. The optical bandgap of the Zn_xCu_1−xO thin films was estimated from the transmittance data by applying the Tauc plot method. A decrease in the band gap was observed at higher doping concentrations. It can be confirmed that no secondary phases are observed at a doping level of 20.0 at. % of zinc, indicating good solubility of zinc in CuO. The analysis and discussion of these findings are included throughout this work to elucidate the controversies noted in the literature. Full article

Indium Tin Oxide (ITO) is one of the most widely used ohmic materials for fabricating ohmic layers in thin-film solar cells. ITO thin layers have reached almost the maximum theoretical conductivity and the lowest practical resistivity. Along with indium’s toxic environmental impact and the high cost of materials, these are the reasons why new materials for efficient, cheaper thin-film transparent ohmic layers are being examined. One of those materials is copper-doped zinc oxide (ZnO:Cu). In this paper, we present a new approach to copper-doped zinc oxide fabrication methods, based on the modern authorial Physical Vapor Co-Deposition technique, which involves optimizing Cu concentration to fine-tune crystal structure, optical band gap, and electrical properties, creating n-type TCOs essential for efficient charge transport in next-generation thin films perovskite solar cells. Full article

The utilization of recycled steel is essential for achieving carbon neutrality and sustainable engineering, yet repeated recycling inevitably leads to the accumulation of residual elements that are difficult to remove during conventional refining. Among them, copper (Cu) readily enriches in scrap-based steels and is a primary cause of surface hot shortness during high-temperature processing due to its segregation at the oxide/steel interface. While the compositional effects of Cu have been extensively studied, the influence of thermo-history associated with different industrial processing routes remains poorly understood. In this work, Cu enrichment during high-temperature oxidation was systematically investigated under thermo-histories representative of conventional hot rolling, thin slab continuous casting and rolling (TSCR), and strip casting. Plain carbon steels containing 0.05–0.30 wt.% Cu were oxidized at 1000–1200 °C, and interfacial microstructures were characterized using SEM–EDS. The results show that Cu enrichment is highly sensitive to both temperature and thermal exposure time, with a critical temperature range of 1100–1150 °C promoting the formation of continuous Cu-rich liquid films. Prolonged thermo-history in conventional hot rolling markedly enhances Cu enrichment, TSCR partially suppresses interfacial segregation, whereas strip casting effectively inhibits Cu enrichment even at elevated Cu contents. These findings highlight thermo-history as a dominant factor controlling Cu-induced surface hot shortness and provide guidance for process optimization in recycled steels. Full article

This study investigates the convective–diffusive Cahn–Hilliard equation, a nonlinear model which is used in real-world applications to phase separation and material pattern formation. Using the modified Sardar sub-problem technique, which is an extension of the Sardar sub-equation approach, we derive multiple classes of exact soliton solutions, including bright, dark, kink, and periodic forms. The parametric behaviors of these solutions are examined and visualized through analytical plots generated in Mathematica and Maple. Furthermore, UV–Vis spectrophotometry is employed to examine the optical response of copper oxide (CuO) thin films. The films exhibited a sharp absorption edge around 380–410 nm and an optical band gap of approximately 2.3 eV, confirming their semiconducting nature. The experimentally observed periodic transmission characteristics are linked with the theoretical soliton profiles predicted by the model. Overall, the proposed analytical and experimental framework establishes a clear connection between nonlinear wave theory and thin-film optical characterization, providing new insights into soliton transformation phenomena in complex material systems. Full article

The emission of greenhouse gases from fossil fuels creates devastating effects on Earth’s atmosphere. Therefore, a clean energy source is required to fulfill the energy demand. Hydrogen is considered an energy vector, and the production of green hydrogen is a promising approach. Photoelectrochemical (PEC) water splitting is the best approach to produced green hydrogen, but the efficiency is low. To produce hydrogen by PEC splitting water, semiconductor photocatalysts have received an enormous amount of academic research in recent years. A new class of co-catalysts based on transition metals has emerged as a powerful tool for reducing charge transfer barriers and enhancing photoelectrochemical (PEC) efficiency. In this study, copper oxide (CuO) and tin oxide ($Sn{O}_2$) multilayer thin films were prepared by thermal evaporation to create an energy gradient between $Sn{O}_2$ and CuO semiconductors for better charge transfer. To improve the crystallinity and reduce the defects, the prepared films were annealed in a tube furnace at 400 °C, 500 °C, and 600 °C in an argon inert gas environment. XRD results showed that $Sn{O}_2$/CuO-600 °C exhibited strong peaks, indicating the transformation from amorphous to polycrystalline. SEM images showed the transformation of smooth dense film to a granular structure by annealing, which is better for charge transfer from electrode to electrolyte. Optical properties showed that the bandgap was decreased by annealing, which might be diffusion of Cu and Sn atoms at the interface. PEC results showed that the $Sn{O}_2$/CuO-600 °C heterostructure exhibits the solar light-to-hydrogen (STH%) conversion efficiency of 0.25%. Full article

The oxygen reduction reaction (ORR) is a crucial process in electrochemical systems, such as fuel cells, as it effectively converts oxygen into water, thereby contributing significantly to sustainable energy generation. In this study, copper oxide (CuO) thin films were deposited onto silver (Ag) substrates using a modified successive ionic layer adsorption and reaction (SILAR) method, followed by an investigation of their electrocatalytic performance toward ORR in an alkaline medium. Comprehensive electrochemical characterizations, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and open circuit potential (OCP), were employed to evaluate catalyst behaviour. Elemental analysis through energy-dispersive X-ray spectroscopy (EDX) confirmed the uniform distribution of CuO, while scanning electron microscopy (SEM) revealed a sponge-like surface morphology which potentially enhances catalytic efficiency. Moreover, EIS spectra revealed a lower charge transfer resistance for the CuO/Ag electrode (3.37 kΩ) compared to bare Ag (4.23 kΩ), reflecting improved ORR kinetics. Among different deposition cycles, 15 SILAR cycles yielded the highest current density of 0.8 mA cm⁻² at 0.60 V. Kinetic analysis revealed that the reaction is irreversible, with a lower value of Tafel slope (32 mV dec⁻¹) and high transfer coefficient (α = 0.45), indicating a concerted reduction mechanism. The ORR pathway was found to follow a four-electron (4e⁻) transfer process. Full article

In this study, barium-doped lanthanum copper oxide (LaCuO) thin films were deposited onto quartz glass substrates using a radio frequency (RF) magnetron sputtering system. The deposited films were subsequently subjected to a selenization annealing process to convert them into barium-doped lanthanum copper oxyselenide (LaCuOSe:Ba) thin films. Selenization was conducted at annealing temperatures of 750 °C, 800 °C, 850 °C, and 900 °C to determine the optimal processing conditions for achieving high-quality LaCuOSe:Ba films. Structural and compositional analyses were performed using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicated that the primary phase of the films under all conditions was LaCuOSe. However, at annealing temperatures above 850 °C, secondary phases, such as Cu₂Se and La₂O₂Se, were formed, indicating partial decomposition or phase separation at elevated temperatures. Among the conditions tested, the film annealed at 850 °C exhibited the most favorable optoelectronic properties. It demonstrated an average visible light transmittance of 59%, an electrical resistivity of 6.37 × 10⁻³ Ω·cm, a carrier mobility of 5.87 cm²/V·s, and a carrier concentration of 2.15 × 10²⁰ cm⁻³. These values yielded the highest calculated figure of merit for transparent conducting films, reaching 1.6 × 10⁻⁵ Ω⁻¹, signifying an optimal balance between transparency and conductivity under these processing conditions. Full article

This study investigated the effects of silver doping, natural ageing, and thermal-induced oxidation on the surface chemistry, morphology, and thermal performance of copper thin films. Ag is used as a doping element in Cu because, in bulk materials it usually refines microstructures, leading to increased hardness and mechanical strength through mechanisms such as solid solution strengthening and twinning. In this work was also used due to its oxidation resistance. Thin films of pure and silver-doped copper (Cu_2Ag and Cu_4Ag) were deposited by RF magnetron sputtering and characterized as-deposited, naturally aged, at room temperature and humidity for one year, and thermally treated at 200 °C, in air. The characterization included X-ray photoelectron spectroscopy (XPS), Atomic Force microscopy (AFM), and thermal analysis, specifically thermal conductivity (λ), thermal diffusivity (α), and thermal capacity (ρ.Cp). Surface XPS analysis revealed changes in copper and silver oxidation states after natural aging and annealing. AFM revelead that the incorporation of silver and heat treatment altered the surface roughness and morphology. Thermal analysis found that for lower silver concentrations, the thermal conductivity increased, but aging and annealing had varying effects depending on the silver content. The Cu_4Ag film showed the best thermal stability after natural ageing. Overall, the results suggest that carefully controlled silver doping can enhance the thermal stability of copper thin films for applications where aging is a concern, such as microelectronics. Full article

Thin films of manganese–nickel–cobalt oxide with graphene (G@MNCO) were deposited on copper foam using electrochemical deposition. NiCo₂O₄ is the main phase in these films. As the proportion of graphene in the precursor solution increases, the oxygen vacancies in the samples also increase. The microstructure of these samples evolves into hierarchical vertical flake structures. Cyclic voltammetry measurements conducted within the potential range of 0–1.2 V reveal that the electrode with the highest graphene content achieves the highest specific capacitance, approximately 475 F/g. Furthermore, it exhibits excellent cycling durability, maintaining 95.0% of its initial capacitance after 10,000 cycles. The superior electrochemical performance of the graphene-enhanced, manganese-doped nickel–cobalt oxide electrode is attributed to the synergistic contributions of the hierarchical G@MNCO structure, the three-dimensional Cu foam current collector, and the binder-free fabrication process. These features promote quicker electrolyte ion diffusion into the electrode material and ensure robust adhesion of the active materials to the current collector. Full article

In this study, the surface photocatalytic activity of an anatase–titanium oxide (TiO_x) film was modified by a thin copper (Cu) layer with the subsequential oxidation annealing process. Through this simple annealing process, the photocatalytic activity of the TiO_x/Cu structure to decompose the methylene blue solution and inhibit the growth of Escherichia coli. could be optimized. With the help of a study on the conductive type required for the oxidation of a single Cu layer, an n/p nanocomposite heterojunction was realized, as this contact system anneals at temperatures of 350 °C and 450 °C. An extra electrical field at the contact interfaces that was be beneficial for separating the photo-generated electron–hole pairs (EHPs) under UV light irradiation was built. The built-in electrical field led to an increase in the structural photocatalytic activity. Moreover, as the p-type cuprous oxide (p-Cu₂O) structure oxidized by the annealed Cu layer could provide a high conduction band that is offset when in contact with the TiO_x film, the photogenerated EHPs on the TiO_x surface could be separated more effectively. Accordingly, the 350 °C-annealed sample, abundant in the nanocomposite TiO_x/Cu₂O heterojunction which could significantly retard the recombination of photo-generated carriers, corresponded to an increase of about 38% in the photocatalytic activity as compared with the single TiO_x film. Full article