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High-entropy alloy (HEA) coatings have demonstrated great potential in anti-wear applications. To further improve the mechanical and tribo-corrosion properties of the HEA coatings, the VAlTiMoSi, (VAlTiMoSi)80C20, and (VAlTiMoSi)60C40 coatings were successfully deposited by DC magnetron sputtering. The microstructure, mechanical, and tribo-corrosion properties of as-deposited and heat-treated coatings were analyzed. All the as-deposited HEA coatings were BCC + amorphous phases. The thermal effect promoted the formation of intermetallic compounds, and the C inhibited the formation of Mo3Si and Ti5Si4. The hardness and elastic modulus of the heat-treated VAlTiMoSi coating were 20.1 and 294.0 GPa, respectively. The heat-treated (VAlTiMoSi)60C40 coating showed the lowest wear rate, namely 5.2 × 10−14 m3·Nm−1, and the best formation ability of passive film in 3.5 wt% NaCl solution.

Photodetectors are one of the most important components for a future "Internet-of-Things" information society. Compared to the mainstream semiconductor-based photodetectors, emerging devices based on two-dimensional (2D) materials and ferroelectrics as well as their hybrid systems have been extensively studied in recent decades due to their outstanding performances and related interesting physical, electrical, and optoelectronic phenomena. In this paper, we review the photodetection based on 2D materials and ferroelectric hybrid systems. The fundamentals of 2D and ferroelectric materials as well as the interaction in the hybrid system will be introduced. Ferroelectricity modulated optoelectronic properties in the hybrid system will be discussed in detail. After the basics and figures of merit of photodetectors are summarized, the 2D-ferroelectrics devices with different structures including p-n diodes, Schottky diodes, and field-effect transistors will be reviewed and compared. The polarization of ferroelectrics offers the possibility of the modulation and enhancement of the photodetection in the hybrid detectors, which will be discussed in depth. Finally, the challenges and perspectives of the photodetectors based on 2D ferroelectrics will be proposed. This Review outlines the important aspects of the recent development of the hybrid system of 2D and ferroelectric materials, which could interact with each other and thus lead to photodetectors with higher performances. Such a Review will be helpful for the research of emerging physical phenomena and for the design of multifunctional nanoscale electronic and optoelectronic devices.

Deep ultraviolet (DUV) photodetection usually relies on wide-bandgap semiconductors, which however face challenges in material growth and doping processes. In this work, we proposed and validated a photodetection scheme based on tunneling barrier modulation, achieving highly sensitive DUV photodetection. Using a two-dimensional van der Waals heterostructure, the device integrates MoS2 as the transporting layer for its high carrier mobility and low dark current, few-layered graphene (FLG) as the photon absorption layer, and hexagonal boron nitride (hBN) as the dielectric barrier. The device exhibits an photoresponsivity of 4.4 × 106 A·W-1 and specific detectivity of 1.4 × 1017 cm ⋅ H z − 1 / 2 ⋅ W − 1 for 250 nm DUV light, with a rejection ratio R250/R450 exceeding 106 for visible light. Unlike conventional photodetectors, the cutoff wavelength is determined by the tunneling barrier rather than the material bandgap. Additionally, this photodetection scheme has been extended to a wide range of materials, utilizing different charge transporting layer (e.g., MoS2, ReS2), barrier layer (e.g., hBN, Al2O3), and photon absorption materials (e.g., FLG, PdSe2, Au, Pd), showcasing its broad adaptability and potential for extensive application. Furthermore, the device has been successfully employed as a power meter for weak UV radiation (0.1 μW·cm-2) and for measuring solar UV irradiance with results matching the meteorological agency's weather reports. Overall, this work introduces an effective approach for developing high-performance DUV photodetectors, highlighting significant potential for applications in the optoelectronic market. Deep ultraviolet (DUV) detectors based on wide-bandgap semiconductors face challenges in the materials growth and optoelectronic properties optimization. Here, the authors realize high-performance DUV photodetectors based on van der Waals heterostructures, where the cutoff wavelength is determined by the tunnelling barrier height rather than the material bandgap. [ABSTRACT FROM AUTHOR]

To ensuring the demand for uranium by utilizing unconventional uranium resources, the development of materials for selective capturing uranyl ions is increasingly important. Hence, the ion-imprinted polymer (IIP) based on specific binding sites was designed and prepared for selective enrichment of uranium from seawater. The existence of specific adsorption sites and the corresponding adsorption mechanism were confirmed by a series of experimental analyses and supported by density functional theory (DFT) calculations. Under the influence of seawater environment, the maximal uranium uptake of IIP reached 58.31 mg g−1. Significantly, the mass ratio of U and V (Sr or Ni) adsorbed by IIP was greater than 15, and the adsorption capacity did not change obviously after five cycles of use. The strategy combining ion imprinting and synergistic interaction is expected to improve uranium extraction performance. [ABSTRACT FROM AUTHOR]

Non-centrosymmetric material systems can generate spontaneous photocurrent without a p-n junction under uniform illumination, which is known as the bulk photovoltaic effect (BPVE). It has garnered significant attention for its application potential in the fields of energy harvesting and photoelectric detection. In this study, we report the BPVE observed in two-dimensional ferroelectric α-In2Se3 multilayer flakes. The reversal in spontaneous photocurrent polarity is observed and associated with the out-of-plane ferroelectric polarization direction. The spontaneous photocurrent originating from the shift current is also polarization-sensitive. The amplitude of spontaneous photocurrent is further increased by one order of magnitude through vacuum annealing. Our results provide a further application potential for new-generation photodetectors based on BPVE with low power consumption and multi-dimensional optoelectronic detection. [ABSTRACT FROM AUTHOR]

Non-centrosymmetric material systems can generate spontaneous photocurrent without a p-n junction under uniform illumination, which is known as the bulk photovoltaic effect (BPVE). It has garnered significant attention for its application potential in the fields of energy harvesting and photoelectric detection. In this study, we report the BPVE observed in two-dimensional ferroelectric α-In2Se3 multilayer flakes. The reversal in spontaneous photocurrent polarity is observed and associated with the out-of-plane ferroelectric polarization direction. The spontaneous photocurrent originating from the shift current is also polarization-sensitive. The amplitude of spontaneous photocurrent is further increased by one order of magnitude through vacuum annealing. Our results provide a further application potential for new-generation photodetectors based on BPVE with low power consumption and multi-dimensional optoelectronic detection. [ABSTRACT FROM AUTHOR]

p-type semiconductors are significant for integrated nanoelectronics. Tellurium (Te), a mono-elemental material, is a p-type semiconductor with high mobility. Its outstanding performance renders it widely applicable in the fields of electronics and optoelectronics. However, the wafer-scale fabrication of Te thin films is challenging. In this study, we reported an ion-bean sputtered Te thin film and investigated the effects of annealing temperatures. Annealing-induced crystallization kinetics were assessed through Raman spectroscopy, x-ray diffraction, and atomic force microscopy. After annealing, the film's conductivity increased from 10−5 to 10−4 S and mobility from 18 to 53 cm2 V−1 s−1. Dual AC resonance tracking switching spectroscopy piezoelectric force microscopy is used to investigate piezo/ferroelectric properties. The coercive voltages are −2 and 4 V respectively, and the effective piezoelectric coefficient (d33) is 40 pm/V. Butterfly and phase-switching loops demonstrate its possible ferroelectricity. The Te thin film has potential applications in optoelectronics, nonvolatile memory devices, and neuromorphic computation. [ABSTRACT FROM AUTHOR]