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2D Ruddlesden─Popper (RP) halide perovskites are attracting increasing research interest due to their enhanced stability compared to 3D perovskites. However, the quantum confinement effect of bulk organic spacers hinders the separation and transport of photo‐generated carriers. Here, a multiple aromatic ring spacer, 3‐benzothiophene methylammonium (BTMA), is developed for a new 2D RP perovskite. The BTMA spacer is demonstrated, with a significant dipole moment, can impair the influence of the quantum confinement effect, and the presence of S atoms or thiophene is favorable for enhancing the interaction between organic spacers and inorganic sheets, improving the stability of perovskites. The perovskite photodetector with BTMA as spacers displays higher device performance than the control sample with 1‐naphthalene methylammonium (NMA) as spacers. Importantly, the outstanding stability of BTMA‐based perovskite films and devices is also confirmed under moisture, heat, and illumination conditions. Combining the asymmetric coplanar nanogap electrode architecture, the photodetectors' enhanced responsivity, detectivity, and external quantum efficiency of 314 A W−1, 3.4 × 1013 Jones, and 865%, respectively, are demonstrated. Importantly, the nanogap photodetectors display promising self‐power characteristics, which makes them attractive for numerous energy‐efficient applications. The work highlights a new route toward developing high‐performance 2D RP perovskite‐based photodetectors with excellent long‐term stability. [ABSTRACT FROM AUTHOR]

Metal oxide thin‐film transistors (TFTs) offer remarkable opportunities for applications in emerging transparent and flexible microelectronics. Unfortunately, their performance is hindered by limitations associated with parasitic effects, such as parasitic electrode overlap capacitances and high contact resistance, which can severely limit their dynamic behavior. Here, an innovative method is reported to fabricate coplanar self‐aligned‐gate (SAG) indium‐gallium‐zinc‐oxide (IGZO) transistors with engineered source/drain contacts. The manufacturing process starts with the deposition and patterning of a gate electrode/dielectric stack and its functionalization with an organic self‐assembled monolayer (SAM) as the surface energy modifier. A second gold (Au) electrode is subsequently deposited over the gate electrode stack. The overlapping region between the two electrodes is removed via self‐delamination under mild sonication, forming perfectly aligned coplanar Au‐Gate‐Au electrodes. Device fabrication is completed with the spin coating of the IGZO precursor, followed by rapid photonic curing. Replacing the gold source/drain contact with bimetallic electrodes such as Au/In and Au/ITO enables a reduction in contact resistance and improves the transistor performance remarkably without increasing manufacturing complexity. The method is highly scalable, robust, and applicable to other semiconductor materials. [ABSTRACT FROM AUTHOR]

Graphene geometric diodes, with applications in THz detection, energy harvesting, and high‐speed rectification, have been previously constrained by graphene quality and geometry feature size. This study presents significant advancements in graphene geometric diodes by employing the h‐BN/monolayer graphene/h‐BN heterojunction and extremely precise electron beam lithography. Two distinct designs of graphene geometric diodes with neck widths of 23 and 26 nm are fabricated, the superior of which demonstrated an asymmetry ratio of 1.97, a zero bias current responsivity of 0.6 A W−1, and a voltage responsivity of 12,000 V W−1, setting new benchmarks for such devices. Integrating this device into a rectification circuit, the experimentally validate that the rectified DC output voltage can be dynamically modulated and even inverted through adjustments to the diode's gate voltage. This behavior aligns seamlessly with graphene's intrinsic tunability of charge carriers, implying promising prospects for the device's application in advanced logic circuits, bidirectional switches, and signal modulation/demodulation techniques. [ABSTRACT FROM AUTHOR]

Layered thio- and seleno-phosphate ferroelectrics, such as CuInP2S6, are promising building blocks for next-generation nonvolatile memory devices. However, because of the low Curie point, the CuInP2S6-based memory devices suffer from poor thermal stability (<42 °C). Here, exploiting the electric field-driven phase transition in the rarely studied antiferroelectric CuCrP2S6 crystals, we develop a nonvolatile memristor showing a sizable resistive-switching ratio of ~ 1000, high switching endurance up to 20,000 cycles, low cycle-to-cycle variation, and robust thermal stability up to 120 °C. The resistive switching is attributed to the ferroelectric polarization-modulated thermal emission accompanied by the Fowler–Nordheim tunneling across the interfaces. First-principles calculations reveal that the good device performances are associated with the exceptionally strong ferroelectric polarization in CuCrP2S6 crystal. Furthermore, the typical biological synaptic learning rules, such as long-term potentiation/depression and spike amplitude/spike time-dependent plasticity, are also demonstrated. The results highlight the great application potential of van der Waals antiferroelectrics in high-performance synaptic devices for neuromorphic computing.Layered thio- and seleno-phosphate ferroelectrics show promise for next-generation memory but have thermal stability issues. Using the electric field-driven phase transition in antiferroelectric CuCrP2S6, the authors introduce a robust memristor, emphasizing the potential of van der Waals antiferroelectrics in advanced neuromorphic computing. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries (LSBs) have shown great potential for application in high-density energy storage systems. However, the performance of LSBs is severely hindered by the shuttle effect and the sluggish reaction kinetics of lithium polysulfides (LiPSs). Here, a Janus Fe3C/N-CNF@RGO electrode consisting of a 1D Fe3C-decorated N-doped carbon nanofibers (Fe3C/N-CNFs) side and a 2D reduced graphene oxide (RGO) side was applied as a free-standing carrier for the Li2S6 catholyte to improve the overall electrochemical performance of LSBs. The Fe3C/N-CNF layer endows the cathode with strong chemisorption abilities for LiPSs and accelerated the redox kinetics via catalyzing the conversion of LiPSs. The 2D RGO sheets serve as a microscopic physical barrier and further resist the shuttling of LiPSs. Like a hunter's trap, behind the trap lies a net. Moreover, the 3D hierarchical conductive network based on 1D N-CNF and 2D RGO sheets enables fast electron transfer. Based on the synergetic effects of chemical immobilization, catalytic abilities, and a physical barrier in a 3D conductive network, LSBs with optimal Fe3C/N-CNF@RGO electrodes exhibit robust long-term cycling stability (a decay rate of only 0.0089% per cycle at 0.5C for 300 cycles), superior rate capabilities (821.7 mA h g−1 at 2.0C), and stable cycling performance at high sulfur loading (6.29 mg cm−2). This work defines an emerging viewpoint relating to the design of novel sulfur carriers with multiple synergistic effects for application in LSBs. [ABSTRACT FROM AUTHOR]

Abstract: Although significant progress has been made towards using ZnO nanofibers (NFs) in future high‐performance and low‐cost electronics, they still suffer from insufficient device performance caused by substantial surface roughness (i.e., irregularity) and granular structure of the obtained NFs. Here, a simple one‐step electrospinning process (i.e., without hot‐press) is presented to obtain controllable ZnO NF networks to achieve high‐performance, large‐scale, and low‐operating‐power thin‐film transistors. By precisely manipulating annealing temperature during NF fabrication, their crystallinity, grain size distribution, surface morphology, and corresponding device performance can be regulated reliably for enhanced transistor performances. For the optimal annealing temperature of 500 °C, the device exhibits impressive electrical characteristics, including a small positive threshold voltage (Vth) of ≈0.9 V, a low leakage current of ≈10−12 A, and a superior on/off current ratio of ≈106, corresponding to one of the best‐performed ZnO NF devices reported to date. When high‐κ AlOx thin films are employed as gate dielectrics, the source/drain voltage (VDS) can be substantially reduced by 10× to a range of only 0–3 V, along with a 10× improvement in mobility to a respectable value of 0.2 cm2 V−1 s−1. These results indicate the potential of these nanofibers for use in next‐generation low‐power devices. [ABSTRACT FROM AUTHOR]

Although In2O3 nanofibers (NFs) are considered as one of the fundamental building blocks for future electronics, the further development of these NFs devices is still seriously hindered by the large leakage current, low on/off current ratio (Ion/Ioff), and large negative threshold voltage (VTH) due to the excess carriers existed in the NFs. A simple one‐step electrospinning process is employed here to effectively control the carrier concentration of In2O3 NFs by selectively doping strontium (Sr) element to improve their electrical device performance. The optimal devices (3.6 mol% Sr doping concentration) can yield the high field‐effect mobility (μfe ≈ 3.67 cm2 V−1 s−1), superior Ion/Ioff ratio (≈108), and operation in the energy‐efficient enhancement‐mode. High‐κ Al2O3 thin films can also be employed as the gate dielectric to give the gate voltage greatly reduced by 10× (from 40 to 4 V) and the μfe substantially increased by 4.8× (to 17.2 cm2 V−1 s−1). The electrospun E‐mode Sr‐In2O3 NF field‐effect transistors (NFFETs) can as well be integrated into full swing of inverters with excellent performances, further elucidating the significant advance of this electrospinning technique toward practical applications for future low‐cost, energy‐efficient, large‐scale, and high‐performance electronics. High‐performance, low‐power, and enhancement‐mode Sr‐doped In2O2 nanofiber (NFs) transistors are demonstrated with impressive electrical characteristics, including a high mobility (3.67 cm2 V−1 s−1) and an impressive Ion/Ioff ratio (≈108). The device operation voltage can be decreased from 40 to 4 V by further employing high‐κ Al2O3 thin films as gate dielectrics, indicating the potency of these NFs for next‐generation electronics. [ABSTRACT FROM AUTHOR]

Wafer-scale transfer processes of 2D materials significantly expand their application space in scalable microelectronic devices with excellent and tunable properties through van der Waals (vdW) stacking. Unlike many 2D materials, wafer-scale transfer of MXene films for vdW contact engineering has not yet been reported. With their rich surface chemistry and tunable properties, the transfer of MXenes can enable enormous possibilities in electronic devices using interface engineering. Taking advantage of the MXene hydrophilic surface, a straightforward, green, and fast process for the transfer of MXene films at the wafer scale (4-inch) is developed. Uniform vdW stacking of several types of large-area heterojunctions including MXene/MXene (Ti 3 C 2 T x , Nb 2 CT x, and V 2 CT x ), MXene/MoS 2 , and MXene/Au is further demonstrated. Multilayer support is applied to minimize damage or deformation in the transfer process of patterned Ti 3 C 2 T x film. It allows us to fabricate thin film transistors and manipulate the MXene/MoS 2 interface through the intercalation of various 2D liquids. Particularly noteworthy is the significant enhancement of the interfacial carrier transfer efficiency by ≈2 orders of magnitude using hydrogen iodide (HI) intercalation. This finding indicates a wide range of possibilities for interface engineering by transferring MXene films and employing liquid-assisted interfacial intercalation., (© 2024 Wiley‐VCH GmbH.)

In recent years, it is urgent and challenging to fabricate highly sensitive and selective gas sensors for breath analyses. In this work, Sr-doped cubic In 2 O 3 /rhombohedral In 2 O 3 homojunction nanowires (NWs) are synthesized by one-step electrospun technology. The Sr doping alters the cubic phase of pure In 2 O 3 into the rhombohedral phase, which is verified by the high-resolution transmittance electron microscopy, X-ray diffraction, and Raman spectroscopy, and is attributable to the low cohesive energy as calculated by the density functional theory (DFT). As a proof-of-concept of fatty liver biomarker sensing, ethanol sensors are fabricated using the electrospun In 2 O 3 NWs. The results show that 8 wt % Sr-doped In 2 O 3 shows the highest ethanol sensing performance with a high response of 21-1 ppm, a high selectivity over other interfering gases such as methanol, acetone, formaldehyde, toluene, xylene, and benzene, a high stability measured in 6 weeks, and also a high resistance to high humidity of 80%. The outstanding ethanol sensing performance is attributable to the enhanced ethanol adsorption by Sr doping as calculated by DFT, the stable rhombohedral phase and the preferred (104) facet exposure, and the formed homojunctions favoring the electron transfer. All these results show the effective structural modification of In 2 O 3 by Sr doping, and also the great potency of the homojunction Sr-doped In 2 O 3 NWs for highly sensitive, selective, and stable breath ethanol sensing.