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Energy storage devices with high energy storage density (UESD), fast operating speed, and high output power are indispensable for modern energy needs. This study presents a wafer-scale epitaxial antiferroelectric ZrO2/TiN heterostructure with a state-of-the-art high UESD of ∼118.6 J cm−3. This significant UESD originates from the predominant [110] antiferroelectric polar axis of ZrO2 oriented out-of-plane, which is confirmed by macroscopic and microscopic analyses of the epitaxial relationships. The construction of a coincidence site lattice indicates the low lattice mismatch between ZrO2(110) and TiN(111). The stacking of ZrO2 sublayers demonstrates the importance of precise epitaxy in controlling crystal orientation, minimizing leakage current, and improving antiferroelectric characteristics. Furthermore, the epitaxial growth of ZrO2 enables a clear observation of inductive-like negative capacitance response, providing insights into antiferroelectric dynamics. The high UESD highlights the significance of atomic layer epitaxy for high-quality antiferroelectric heterostructures, particularly in epitaxial growth methods and energy storage applications. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the indirect effects on the properties of ZrO2 films deposited by atomic layer deposition (ALD) when an Mg-Ca alloy is modified through equal-channel angular pressing (ECAP) following extrusion. The study aims to understand how the increase in CaO content in the native oxide layer of the Mg-Ca alloy influences the crystallinity and defect density of the ZrO2 film. Consequently, the corrosion protection performance of the ZrO2 film is enhanced by 1.2 to 1.5 times. A reduction in the anti-scratch property of the ZrO2 film was also observed, with a critical load reduction of 34 μN. This research provides a detailed analysis of the modifications induced by ECAP on the as-extruded Mg-Ca alloy and its subsequent impact on the properties of the ZrO2 film. [ABSTRACT FROM AUTHOR]

In this study, platinum (Pt) and tungsten (W), two materials with dissimilar coefficients of thermal expansion (CTE) and work functions (WF), are used as the top electrode (TE) and the bottom electrode (BE) in metal/ferroelectric/metal (MFM) structures to explore the ferroelectricity of hafnium zirconium oxide (HZO) with a thickness less than 10 nm. The electrical measurements indicate that a higher CTE mismatch between HZO and TE/BE is beneficial for enhancing the ferroelectric properties of nanoscale HZO thin films. The different WFs of TE and BE generate a built-in electric field in the HZO layer, leading to shifts in the hysteresis loops and the capacitance–voltage characteristics. The structural characterizations reveal that the preferred formation of the orthorhombic phase in HZO is dominated by the W BE. The device in which W is used as the TE and BE (the W/HZO/W MFM structure) presents the optimal ferroelectric performance of a high remanent polarization (2 P r = 55.2 μ C cm−2). The presence of tungsten oxide (WO x ) at the W/HZO interfaces, as revealed by high-resolution transmission microscopy, is also responsible for the enhancement of ferroelectric properties. This study demonstrates the significant effects of different CTEs and WFs of TE and BE on the properties of ferroelectric HZO thin films. [ABSTRACT FROM AUTHOR]

For cardiopulmonary bypass, the polyvinyl chloride (PVC) circuit which can initiate the activation of platelets and the coagulation cascade after blood cell contacting is the possible detrimental effect. Surface coating of the PVC tubing system can be an effective approach to enhance circuit's hemocompatibility. In this study, aluminum oxide (Al2O3) thin films were deposited through thermal atomic layer deposition (T‐ALD) or plasma‐enhanced ALD (PE‐ALD) on PVC samples, and the anticoagulation of the Al2O3‐coated PVC samples was demonstrated. The results revealed that Al2O3 deposition through ALD increased surface roughness, whereas T‐ALD had a relative hydrophilicity compared with blank PVC and PE‐ALD. Whole blood immersion tests showed that blood clots formed on blank PVC and that a large amount of red blood cells was found on PE‐ALD substrates, whereas less blood cells were noted in T‐ALD samples. Both T‐ALD and PE‐ALD Al2O3 films did not cause activation of blood cells, as evidenced in CD3+/CD4+/CD8+, CD61+/CD62P+, and CD45+/CD42b+ populations. Analysis of serum coagulation factors showed that a lower amount of prothrombin was absorbed on T‐ALD Al2O3 samples than that on blank PVC. For albumin and fibrinogen immersion tests, immunostaining and scanning electron microscopy further revealed that a thin albumin layer was absorbed on T‐ALD Al2O3 substrates but not on PVC samples. This study revealed that deposition of Al2O3 films by T‐ALD can improve anticoagulation of the PVC tubing system. [ABSTRACT FROM AUTHOR]

Polycrystalline HfZrO2 (HZO) film can be fabricated on as-extruded Mg–Ca alloy, which is identified by the results of XRD and TEM. HZO film can improve the corrosion resistance of as-extruded Mg–Ca alloy to further result in a decrease in the corrosion rate of Mg–Ca alloy. Corrosion current density, pH value evaluation, and the corrosion surface image provide evidence of improvement in corrosion rate. Compared with ZrO2 film, HZO film shows better short-term corrosion resistance. The results of WST-1 assay and LDH assay show that HZO film has low toxicity and is suitable for the protective coating of biological implants. [ABSTRACT FROM AUTHOR]

Ferroelectric properties of Hf 0.5 Zr 0.5 O 2 are strongly correlated with its crystallographic orientation, with the [001] direction serving as the polar axis. However, the epitaxial growth of highly polar-axis-oriented Hf 0.5 Zr 0.5 O 2 layers with pronounced ferroelectricity is rarely reported. Here epitaxial (001)-oriented Hf 0.5 Zr 0.5 O 2 thin films grown by atomic layer epitaxy (ALE) is demonstrated, which achieve a state-of-the-art ferroelectric polarization up to 78.9 µC cm -2 . The epitaxial Hf 0.5 Zr 0.5 O 2 layer experiences a lattice reorientation from (010) to (001) during the wake-up process, as evidenced by plane-view precession electron diffraction. Accordingly, a two-step, 90° ferroelastic domain switching model is proposed to elucidate multiple polarization switching. Furthermore, the observed polarization switching dynamics closely match with the time-resolved negative capacitance, which is quantified as an equivalent high dielectric constant of -170. This study highlights the capability of ALE to precisely control the crystallographic orientation of Hf 0.5 Zr 0.5 O 2 thin films, providing deep insights into fundamental ferroelectric mechanisms., (© 2024 Wiley‐VCH GmbH.)