Search Results (323)

In this study, Hf_0.5Zr_0.5O₂ (HZO) thin-films were deposited using a Co-plasma atomic layer deposition (CPALD) process that combined both remote plasma and direct plasma, for the development of ferroelectric memory devices. Ferroelectric capacitors with a symmetric hybrid TiN/W/HZO/W/TiN electrode structure, incorporating W electrodes as insertion layers, were fabricated. Rapid thermal annealing (RTA) was subsequently employed to control the crystalline phase of the films. The electrical and structural properties of the capacitors were analyzed based on the RTA temperature, and the presence, thickness, and position of the W insertion electrode layer. Consequently, the capacitor with 5 nm-thick W electrode layers inserted on both the top and bottom sides and annealed at 700 °C exhibited the highest remnant polarization (2P_r = 61.0 μC/cm²). Moreover, the symmetric hybrid electrode capacitors annealed at 500–600 °C also exhibited high 2P_r values of approximately 50.4 μC/cm², with a leakage current density of approximately 4 × 10⁻⁵ A/cm² under an electric field of 2.5 MV/cm. The findings of this study are expected to contribute to the development of electrode structures for improved performance of HZO-based ferroelectric memory devices. Full article

Background/Objectives: The increasing demand for aesthetics in dentistry has driven significant advancements in both materials and techniques. The primary cause of ceramic detachment in dental restorations is extensive mechanical stress, which often results in detachment and clinical complications. This study aims to improve the bond strength between NiCr-based metal frameworks and ceramic coatings by introducing biocompatible inorganic MeSiON thin films (Me = Cr or Zr) as interlayers. Methods: MeSiON coatings with a thickness of ~2 μm were deposited on NiCr alloy using cathodic arc evaporation. To tailor the stoichiometry, morphology, and mechanical properties of the coatings, the substrate bias voltage was varied: −50 V, −100 V, −150 V, −200 V. Structural and surface characterization was performed using SEM/EDS, XRD, profilometry, and contact angle analysis. The coating adhesion was evaluated by using standardized scratch testing, while the bond strength was evaluated using a three-point bending test. Results: The NiCr alloy exhibited a dendritic microstructure, and the ceramic layer consisted mainly of quartz, feldspar, kaolin, and ZrO₂. ZrSiON coatings showed superior roughness, elemental incorporation, and adhesion compared to Cr-based coatings, these properties being further improved by increasing the substrate bias. The highest bond strength was achieved with a ZrSiON coating deposited at −200 V, a result we attributed to increased surface roughness and mechanical interlocking at the ceramic-metal interface. Conclusions: CrSiON and ZrSiON interlayers enhanced ceramic-to-metal adhesion in NiCr-based dental restorations. The enhancement in bond strength is primarily ascribed to substrate bias-induced modifications in the coating’s stoichiometry, roughness, and adhesion. Full article

Residual stress plays a crucial role in determining the structural reliability and mechanical performance of nano-multilayers. In the present study, nano-multilayers composed of ZrO_xN_y and V₂O₃ were deposited via magnetron sputtering, with the N:Ar flow ratio systematically varied during the process. Through the precise control of the deposition conditions, the compressive residual stress within the films was effectively reduced to approximately 0 GPa, thereby improving their mechanical robustness. It was observed that the optimization of the stress distribution was strongly influenced by the structural symmetry of the multilayer configuration. This symmetrical design not only mitigated stress accumulation but also ensured uniform mechanical response throughout the multilayer structure. The results from nanoindentation testing revealed a steady hardness value near 10.6 GPa. Furthermore, the maximum H³/E² and H/E ratios recorded were 0.054 GPa and 0.073, respectively, suggesting enhanced resistance to both plastic deformation and cracking. Full article

BaTiO₃-based lead-free ferroelectric films with a large recoverable energy density (W_rec) and a high energy efficiency (η) are crucial components for next-generation dielectric capacitors, which are used in energy conditioning and storage applications in integrated circuits. In this study, grain-engineered (Ba_0.95,Sr_0.05)(Zr_0.2,Ti_0.8)O₃ (BSZT) ferroelectric thick films (~500 nm) were prepared on Si substrates. These films were deposited at 350 °C, 100 °C lower than the temperature at which the LaNiO₃ buffer layer was deposited on Pt/Ti. This method reduced the (001) grain population due to a weakened interface growth mode, while promoting volume growth modes that produced (110) and (111) grains with a high polarizability. As a result, these films exhibited a maximum polarization of ~88.0 μC/cm², a large W_rec of ~203.7 J/cm³, and a high energy efficiency η of 81.2% (@ 6.4 MV/cm). The small-field dielectric constant nearly tripled as compared with that of the same BSZT/LaNiO₃ heterostructure deposited at the same temperature (350 °C or 450 °C). The enhanced linear dielectric response, delayed ferroelectric polarization saturation, and increased dielectric strength due to the nano-grain size, collectively contributed to the improved energy storage performance. This work provides a novel approach for fabricating high-performance dielectric capacitors for energy storage applications. Full article

(1) Background: Asomate, as a dithiocarbamate compound, is moderately toxic to the human body; thus, it is necessary to develop a rapid and efficient method for detection. To meet this need, this study introduced a rapid, non-destructive, and efficient method for detecting asomate residues on the surface of apples based on surface-enhanced Raman spectroscopy (SERS) combined with flexible substrates. (2) Methods: Concave Au nanorods (AuCNAs) were synthesized in advance. Then, the AuCNAs were loaded on an electrostatically spun film to generate a flexible TiO₂/ZrO₂/AuCNAs substrate for detection. (3) Results: The flexible substrate exhibited strong SERS activity, with an enhancement factor (EF) up to 9.40 × 10⁷ for 4-MBA. Meanwhile, the finite-difference time-domain (FDTD) simulation showed that the localized surface plasmon resonance (LSPR) effects related to the enhancement of the SERS signal are mainly generated from the ‘hot spots’ in AuCNAs. The density functional theory (DFT) simulation detailedly revealed that the SERS peaks could be generated by the interaction among asomate molecules, disassociated Au atoms, and Au facets. Moreover, the asomate in apple peel was analyzed with the limit of detection (LOD) as low as below 10 nM, allowing for the rapid detection of asomate directly on apple peels. (4) Conclusions: The flexible TiO₂/ZrO₂/AuCNAs film can be used for the in situ detection of asomate in apple peel at low concentrations. Moreover, the simulation methods, including FDTD and DFT, explained the mechanism of SERS from the flexible substrates. Full article

Flexible thin-film capacitors have gained a lot of attention in energy storage applications because of their high energy storage densities and efficient charge–discharge performances. Among these materials, antiferroelectric compounds with low residual polarization and strong saturation polarization have shown great promise. However, their comparatively low breakdown strength continues to be a major issue restricting further developments in their energy storage performance. While La³⁺ doping has been explored as a means to enhance the energy storage capabilities of antiferroelectric thin films, the specific influence of La³⁺ on breakdown strength and the underlying mechanism of phase transitions have not been thoroughly investigated in existing research. In this study, Pb_1−3x/2La_xZrO₃ thin films were successfully synthesized and deposited on mica substrates via the sol–gel process. By varying the concentration of La³⁺ ions, a detailed examination of the films’ microstructures, electrical properties, and energy storage performances was carried out to better understand how La³⁺ doping influences both breakdown strength and energy storage characteristics. The results show that doping with La³⁺ significantly improves the breakdown strength of the films, reduces the critical phase transition electric field (E_F-E_A), and enhances their energy storage capabilities. Notably, the Pb_0.91La_0.06ZrO₃ thin film achieved an impressive energy storage density of 34.9 J/cm³ with an efficiency of 58.3%, and at the maximum electric field strength of 1541 kV/cm, the recoverable energy density (W_rec) was 385% greater than that of the PbZrO₃ film. Additionally, the film still maintains good energy storage performance after 10⁷ cycles and 10⁴ bending cycles. These findings highlight the potential of flexible antiferroelectric Pb_0.91La_0.06ZrO₃ thin films for future energy storage applications. Full article

The polarization fatigue of PbZr_1−xTi_xO₃ (PZT) films is one of the most serious failure issues in their practical application. In the present work, Ba_0.3Sr_0.7Zr_0.18Ti_0.82O₃ (BSZT) was used as an inserting layer to improve the polarization fatigue of PbZr_0.50Ti_0.50O₃ thick film. PZT thick films and BSZT layers were deposited via magnetron sputtering technology. The effects of BSZT layer on the dielectric response, remanent polarization, and fatigue resistance of PZT thick films were investigated experimentally. The results showed that the dielectric constant increased from 457 to 880 (1 MHz), and the reversible/irreversible Rayleigh coefficients were also enhanced. The remanent polarization P_r of the PZT thick films increased from 37 μC/cm² to 42.4 μC/cm². After a 1.08 × 10⁹ cycles polarization fatigue test, the ferroelectric polarization loss was 9% for the PZT thick film at 368 kV/cm. The reversible/irreversible Rayleigh coefficients had a very small decline, of only 5% and 2%, respectively. This demonstrates that, different from the previously reported buffer layers, BSZT buffer layers can simultaneously enhance the dielectric and ferroelectric properties and improve the polarization fatigue of PZT thick films. Full article

In this study, polymer films based on the inorganic sorbents Al₂O₃, ZrO₂ and SiO₂-phenyl with repellent N,N-diethyl-3-methylbenzamide were prepared and used as functional textile coatings. The high sorption activity of oxides with respect to N,N-diethyl-3-methylbenzamide (63–239 mg/g) allows for the use of these compounds as repellent carrier materials, and their mixture with polyacrylates allows for the formation of functional coatings–polymer films. Scanning electron microscopy and Fourier transform infrared spectroscopy results revealed that the inorganic sorbents Al₂O₃, ZrO₂ and SiO₂-phenyl were successfully anchored in the polyacrylate structure, and the FTIR spectra confirmed the presence of repellent molecules. The thermal diffusion parameters of N,N-diethyl-3-methylbenzamide were also calculated via thermogravimetric analysis and high-performance liquid chromatography with diode array detection. The highest thermal diffusion rates and concentrations were observed for the material with Al₂O₃ (up to 148.3∙10⁻⁹ mol at 200 °C), and lower values for ZrO₂ and SiO₂-phenyl (up to 15.2∙10⁻⁹ mol and 34.3∙10⁻⁹ mol at 200 °C, respectively). The heat flux parameter J_f was also calculated according to Onsager’s theory and Fourier’s law. The release of repellent from polymeric materials can be achieved by applying less heat than that required to reach the boiling point of N,N-diethyl-3-methylbenzamide. Full article

Ferroelectric thin films with a high dielectric tunability (η) have great potential in electrically tunable applications, including microwave tunable devices such as phase shifters, filters, delay lines, etc. Using a modified Landau–Devonshire type thermodynamic potential, we show that the dielectric tunability η of a (001) tetragonal ferroelectric film can be analytically solved. After a survey of materials, a large η value above 60% was predicted to be achievable in a (001)-oriented tetragonal Pb(Zr_0.52Ti_0.48)O₃ (PZT) film. Experimentally, (001)-oriented PZT thin films were prepared on LaNiO₃-coated (100) SrTiO₃ substrates by using pulsed laser deposition (PLD). These films exhibited good dielectric tunability (η ~ 67.6%) measured at a small electric field E of ~250 kV/cm (corresponding to 5 volts for a 200 nm thick film). It only dropped down to ~54.2% when E was further reduced to 125 kV/cm (2.5 volts for 200 nm film). The measured dielectric tunability η as functions of the applied electric field E and measuring frequency f are discussed for a 500 nm thick PZT film, with the former well described by the theoretical η(E) curves and the latter showing a weak frequency dependence. These observations validate our integrated approach rooted in a theoretical understanding. Full article

This work systematically analyses the electrical and structural properties of a bilayer gate dielectric composed of Sm₂O₃ and ZrO₂ on a 4H-SiC substrate. The bilayer thin film was fabricated using a sputtering process, followed by a dry oxidation step with an adjusted oxygen-to-nitrogen (O₂:N₂) gas concentration ratio. XRD analysis validated formation of an amorphous structure with a monoclinic phase for both Sm₂O₃ and ZrO₂ dielectric thin films. High-resolution transmission emission (HRTEM) analysis verified the cross-section of fabricated stacking layers, confirmed physical oxide thickness around 12.08–13.35 nm, and validated the amorphous structure. Meanwhile, XPS confirmed the presence of more stoichiometric dielectric oxide formation for oxidized/nitrided O₂:N₂-incorporated samples, and more sub-stochiometric thin films for samples only oxidized in ambient O₂. The oxidation/nitridation processes with N₂ incorporation influenced the band offsets and revealed conduction band offsets (CBOs) ranging from 2.24 to 2.79 eV. The affected charge movement and influenced electrical performance where optimized samples with gas concentration ratio of 90% O₂:10% N₂ achieved the highest electrical breakdown field of 10.1 MV cm⁻¹ at a leakage current density of 10⁻⁶ A cm⁻². This gate stack also improved key parameters such as the effective dielectric constant ($k_{eff}$) up to 29.75, effective oxide charge ($Q_{eff}$), average interface trap density ($D_{it}$), and slow trap density (STD). The bilayer gate stack of Sm₂O₃ and ZrO₂ revealed potential attractive characteristics as a candidate for high-k gate dielectric applications in metal-oxide-semiconductor (MOS)-based devices. Full article

Solution-processed metal oxide dielectrics often result in unstable thin-film transistor (TFT) performance, hindering the development of next-generation metal oxide electronics. In this study, we prepared fluorine (F)-doped zirconium oxide (ZrO₂) dielectric layers using a chemical solution method to construct TFTs. The characterization by X-ray photoelectron spectroscopy (XPS) revealed that appropriate fluoride doping significantly reduces oxygen vacancies and the concentration of hydroxyl groups, thereby suppressing polarization processes. Subsequently, the electrical properties of Al/F:ZrO₂/n⁺⁺Si capacitors were evaluated, demonstrating that the optimized 10% F:ZrO₂ dielectric exhibits a low leakage current density and stable capacitance across a wide frequency range. Indium zinc oxide (IZO) TFTs incorporating 10% F:ZrO₂ dielectric layers were then fabricated. These devices displayed reliable electrical characteristics, including high mobility over a broad frequency range, reduced dual-sweep hysteresis, and excellent stability under positive-bias stress (PBS) after three months of aging. These findings indicate that the use of the fluorine-doped ZrO₂ dielectric is a versatile strategy for achieving high-performance metal oxide thin-film electronics. Full article

Zr-4 alloy tubes, as the primary cladding material in nuclear reactor cores, face the critical challenge of oxidative attack in 1200 °C steam environments. To address this issue, high-temperature oxidation-resistant coatings fabricated via extreme high-speed laser cladding (EHLA) present a promising mitigation strategy. In this study, Y₂O₃-modified (0.0–5.0 wt.%) Cr/FeCrAl composite coatings were designed and fabricated on Zr-4 substrates using the EHLA process, followed by systematic investigation of Y doping effects on coating microstructures and steam oxidation resistance (1200 °C, H₂O atmosphere). Experimental results demonstrate that Y₂O₃ doping remarkably enhanced the oxidation resistance, with optimal performance achieved at 2.0 wt.% Y₂O₃ (31% oxidation mass gain compared to the substrate after 120-min exposure). Microstructural analysis reveals that the dense grain boundary network facilitates rapid surface diffusion of Al, promoting continuous Al₂O₃ protective film formation. Additionally, Y segregation at grain boundaries suppressed outward diffusion of Cr³⁺ cations, effectively inhibiting void formation at the oxide-coating interface and improving interfacial stability. The developed rare-earth-oxide-doped composite coating via extreme high-speed laser cladding process shows promising applications in surface-strengthening engineering for nuclear reactor Zr-4 alloy cladding tubes, providing both theoretical insights and technical references for the design of high-temperature oxidation-resistant coatings in nuclear industry. Full article

The transition of SiC MOSFET structure from planar to trench-based architectures requires the optimization of gate dielectric layers to improve device performance. This study utilizes a range of characterization techniques to explore the interfacial properties of ZrO₂ and SiO₂/ZrO₂ gate dielectric films, grown via atomic layer deposition (ALD) in SiC epitaxial trench structures to assess their performance and suitability for device applications. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements showed the deposition of smooth film morphologies with roughness below 1 nm for both ZrO₂ and SiO₂/ZrO₂ gate dielectrics, while SE measurements revealed comparable physical thicknesses of 40.73 nm for ZrO₂ and 41.55 nm for SiO₂/ZrO₂. X-ray photoelectron spectroscopy (XPS) shows that in SiO₂/ZrO₂ thin films, the binding energies of Zr 3d_5/2 and Zr 3d_3/2 peaks shift upward compared to pure ZrO₂. Electrical characterization showed an enhancement of E_BR (3.76 to 5.78 MV·cm⁻¹) and a decrease of I_{ON_EBR} (1.94 to 2.09 × 10⁻³ A·cm⁻²) for the SiO₂/ZrO₂ stacks. Conduction mechanism analysis identified suppressed Schottky emission in the stacked film. This indicates that the incorporation of a thin SiO₂ layer effectively mitigates the small bandgap offset, enhances the breakdown electric field, reduces leakage current, and improves device performance. Full article

Polyvinyl alcohol (PVA) is used in various fields; however, its highly flammable property greatly limits its application. In order to improve the flame-retardant properties of PVA, one method is by adding flame retardants directly, while another method is through grafting, cross-linking and hydrogen bonding. A flame retardant, 9, 10-dihydro-9, 10-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-vinyltrimethoxysilane (VTES), was synthesized through the addition reaction of a P–H bond on the DOPO and unsaturated carbon–carbon double bonds on the VTES. Then, the DOPO-VTES and zirconium phosphate (α-ZrP) were blended with PVA to cast a film, in which DOPO-VTES was grafted onto the PVA by cross-linking the hydroxyl group in the molecular structure of DOPO-VTES with the hydroxyl group in PVA; α-ZrP was used as a cooperative agent of DOPO-VTES. The cone calorimetry test (CCT) showed a significant reduction in both the heat release rate (HRR) and total heat release rate (THR) for the flame-retardant PVA films compared to pure PVA. Additionally, thermogravimetric analysis (TGA) revealed a higher residual char content in the flame-retardant PVA films than in pure PVA. These findings suggested that the combination of DOPO-VTES and α-ZrP could improve the flame retardancy of PVA. The cooperative flame-retardant mode of action at play was possibly that DOPO in the DOPO-VTES acted as a mainly gas-phase flame retardant, which yielded a PO radical; VTES in the DOPO-VTES produced silicon dioxide (SiO₂), which acted as a thermal insulator; and α-ZrP catalyzed the carbonization of the PVA. By combining DOPO-VTES with α-ZrP, a continuous dense carbon layer was formed, which effectively inhibited oxygen and heat exchange, resulting in a flame-retardant effect. It is expected that flame-retardant films for PVA have a broad development prospect and potential in the fields of packaging materials, electronic appliances, and lithium-ion battery separators. Full article

The low energy density (U_d) of polymeric dielectrics is unfavorable for the integration and miniaturization of electronics, thus limiting their application prospects. Introducing high-ε_r (dielectric constant) ceramic nanofillers to polymer matrices is the most common strategy to enhance their ε_r, and hence their U_d. By comparison, enhancing breakdown strength (E_b) is a more effective strategy to enhance U_d. Herein, 0.6BaTiO₃-0.4Bi(Mg_0.5Ti_0.5)O₃ and 0.85BaTiO₃-0.15Bi(Mg_0.5Zr_0.5)O₃ nanofibers coated with SiO₂ were utilized as fillers in PVDF-based nanocomposites. The combination of experimental and simulation results suggests that the intrinsic properties of nanofillers are the determining factor of the E_b of polymer-based nanocomposites, and SiO₂ coating and film structure design are effective strategies to enhance their E_b, and consequently their U_d. As a result, the sandwich-structured PVDF/6 wt% 0.85BaTiO₃-0.15Bi(Mg_0.5Zr_0.5)O₃@SiO₂ nanofiber within PVDF/PVDF nanocomposite films achieved a maximum U_d of 11.1 J/cm³ at an E_b of 458 MV/m, which are 2.15 and 1.40 times those of pristine PVDF, respectively. Full article