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Resistive random access memory (RRAM) crossbar arrays require the highly nonlinear selector with high current density to address a specific memory cell and suppress leakage current through the unselected cell. 3D monolithic integration of RRAM array requires selector devices with a small footprint and low‐temperature processing for ultrahigh‐density data storage. Here, an ultrathin two‐terminal n‐p‐n selector with 2D transition metal dichalcogenides (TMDs) is designed by a low‐temperature transfer method. The van der Waals contact between transferred Au electrodes and TMDs reduces the Fermi level pinning and retains the intrinsic transport behavior of TMDs. The selector with a single type of TMD exhibits a trade‐off between current density and nonlinearity depending on the barrier height. By tuning the Schottky barrier height and controlling the thickness of p‐type WSe2 in MoS2/WSe2/MoS2 n‐p‐n selector for a punch‐through transport, the selector shows high nonlinearity (≈ 230) and high current density (2 × 103 A cm−2) simultaneously. The n‐p‐n selectors are further integrated with a bipolar hexagonal boron nitride memory and calculate the maximum crossbar size of the 2D material‐based one‐selector one‐resistor according to a 10% read margin, which offers the possible realization of future 3D monolithic integration. [ABSTRACT FROM AUTHOR]

Artificial retina technologies aim to restore visual function by mimicking the natural processes of the eye. These biomimetic devices can convert light into electrical signals that the brain can interpret as visual information, bypassing damaged or non‐functional cells of the eye. To be effective, these devices should possess high sensitivity to light, high spatial resolution, biocompatibility, power efficiency, and so on. Recently, 2D semiconductor materials have appeared as a promising candidate for artificial retinal devices, thanks to their excellent optoelectronic properties, ultrathin body, flexible nature, and biocompatibility. Here the recent developments in the field of 2D semiconductors‐based optoelectronics for visual function recovery are reviewed and their potential applications are discussed. The photodetector, optoelectronic memory, and artificial synapse mechanisms and devices utilized in artificial systems that are based on 2D semiconductor materials are summarized. Additionally, a range of application scenarios for devices that are inspired by retinal cells and vision systems is explored. Finally, it is concluded with an overview of the critical technical challenges and strategies that must be addressed for the successful development of artificial retina technologies. It also highlights the potential for new applications in other fields, such as robotics and artificial intelligence. [ABSTRACT FROM AUTHOR]

Supercapacitors with the advantages of high power density and fast discharging rate have full applications in energy storage. However, the low energy density restricts their development. Conventional methods for improving energy density are mainly confined to doping atoms and hybridizing with other active materials. Herein, a Co3O4/g‐C3N4 p–n junction with excellent capacity is developed and its application in an all‐solid‐state flexible device is demonstrated, whose capacity and energy density are considerably enhanced by simulated solar light irradiation. Under photoirradiation, the capacity is increased by 70.6% at the maximum current density of 26.6 mA cm−2 and a power density of 16.0 kW kg−1. The energy density is enhanced from 7.5 to 12.9 Wh kg−1 with photoirradiation. The maximum energy density reaches 16.4 Wh kg−1 at a power density of 6.4 kW kg−1. It is uncovered that the lattice distortion of Co3O4, reduces defects of g‐C3N4, and the facilitated photo‐generated charge separation by the Co3O4/g‐C3N4 p–n junction all make contributions to the promoted electrochemical storage performance. This work may provide a new strategy to enhance the energy density of supercapacitors and expand the application range of photocatalytic materials. [ABSTRACT FROM AUTHOR]

Large-scale, high-quality, and uniform monolayer molybdenum disulfide (MoS 2 ) films are crucial for their applications in next-generation electronics and optoelectronics. Epitaxy is a mainstream technique for achieving high-quality MoS 2 films and is demonstrated at a wafer scale up to 4-in. In this study, the epitaxial growth of 8-in. wafer-scale highly oriented monolayer MoS 2 on sapphire is reported as with excellent spatial homogeneity, using a specially designed vertical chemical vapor deposition (VCVD) system. Field effect transistors (FETs) based on the as-grown 8-in. wafer-scale monolayer MoS 2 film are fabricated and exhibit high performances, with an average mobility and an on/off ratio of 53.5 cm 2 V -1 s -1 and 10 7 , respectively. In addition, batch fabrication of logic devices and 11-stage ring oscillators are also demonstrated, showcasing excellent electrical functions. This work may pave the way of MoS 2 in practical industry-scale applications., (© 2024 The Authors. Advanced Materials published by Wiley‐VCH GmbH.)

High energy density and intrinsic safety are the central pursuits in developing rechargeable Zinc-ion batteries (ZIBs). The capacity and stability of nickel cobalt oxide (NCO) cathode are unsatisfactory because of its semiconductor character. Herein, we propose a built-in electric field (BEF) approach by synergizing cationic vacancies and ferroelectric spontaneous polarization on cathode side to facilitate electron adsorption and suppress zinc dendrite growth on the anode side. Concretely, NCO with cationic vacancies was constructed to expand lattice spacing for enhanced zinc-ion storage. Heterojunction with BEF leads to the Heterojunction//Zn cell exhibiting a capacity of 170.3 mAh g -1 at 400 mA g -1 and delivering a competitive capacity retention of 83.3 % over 3000 cycles at 2 A g -1 . We conclude the role of spontaneous polarization in suppressing zinc dendrite growth dynamics, which is conducive to developing high-capacity and high-safety batteries via tailoring defective materials with ferroelectric polarization on the cathode., (© 2023 Wiley-VCH GmbH.)

1D hollow nanostructures combine the advantages of enhanced surface-to-volume ratio, short transport lengths, and efficient 1D electron transport, which can provide more design ideas for the preparation of highly active oxygen evolution (OER) electrocatalysts. A unique architecture of dual-phase octahedral CoMn 2 O 4 /carbon hollow nanofibers has been prepared via a two-step heat-treatment process including preoxidation treatment and Ostwald ripening process. The hollow and porous structures provide interior void spaces, large exposed surfaces, and high contact areas between the nanofibers and electrolyte and the morphology can be engineered by adjusting the heating conditions. Due to the intimate electrical and chemical coupling between the oxide nanocrystals and integrated carbon, the dual-phase octahedral CoMn 2 O 4 /carbon hollow nanofibers exhibit excellent OER activity with overpotentials of 337 mV at current density of 10 mA cm -2 and Tafel slope of 82 mV dec -1 . This approach will lead to the new perception of design issue for the nanoarchitecture with fine morphology, structures, and excellent electrocatalytic activity., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)