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Transistor scaling has become increasingly difficult in the dynamic random access memory (DRAM). However, vertical devices will be good candidates for 4F2 DRAM cell transistors (F = pitch/2). Most vertical devices are facing some technical challenges. For example, the gate length cannot be precisely controlled, and the gate and the source/drain of the device cannot be aligned. Recrystallization-based vertical C-shaped-channel nanosheet field-effect transistors (RC-VCNFETs) were fabricated. The critical process modules of the RC-VCNFETs were developed as well. The RC-VCNFET with a self-aligned gate structure has excellent device performance, and its subthreshold swing (SS) is 62.91 mV/dec. Drain-induced barrier lowering (DIBL) is 6.16 mV/V.

At sub-3 nm nodes, the scaling of lateral devices represented by a fin field-effect transistor (FinFET) and gate-all-around field effect transistors (GAAFET) faces increasing technical challenges. At the same time, the development of vertical devices in the three-dimensional direction has excellent potential for scaling. However, existing vertical devices face two technical challenges: “self-alignment of gate and channel” and “precise gate length control”. A recrystallization-based vertical C-shaped-channel nanosheet field effect transistor (RC-VCNFET) was proposed, and related process modules were developed. The vertical nanosheet with an “exposed top” structure was successfully fabricated. Moreover, through physical characterization methods such as scanning electron microscopy (SEM), atomic force microscopy (AFM), conductive atomic force microscopy (C-AFM) and transmission electron microscopy (TEM), the influencing factors of the crystal structure of the vertical nanosheet were analyzed. This lays the foundation for fabricating high-performance and low-cost RC-VCNFETs devices in the future.

Abstract Metasurfaces have exhibited exceptional proficiency in precisely modulating light properties within narrow wavelength spectra. However, there is a growing demand for multi-resonant metasurfaces capable of wavefront engineering across broad spectral ranges. In this study, we introduce a microcavity-assisted multi-resonant metasurface platform that integrates subwavelength meta-atoms with a specially designed distributed Bragg reflector (DBR) substrate. This platform enables the simultaneous excitation of various resonant modes within the metasurface, resulting in multiple high-Q resonances spanning from the visible to the near-infrared (NIR) regions. The developed metasurface generates up to 15 high-Q resonant peaks across the visible-NIR spectrum, achieving a maximum efficiency of 81% (70.7%) in simulation (experiment) with an average efficiency of 76.6% (54.5%) and a standard deviation of 4.1% (11.1%). Additionally, we demonstrate the versatility of the multi-resonant metasurface in amplitude, phase, and wavefront modulations at peak wavelengths. By integrating structural color printing and vectorial holographic imaging, our proposed metasurface platform shows potential for applications in optical displays and encryption. This work paves the way for the development of next-generation multi-resonant metasurfaces with broad-ranging applications in photonics and beyond.

Abstract Exceptional points (EPs) can achieve intriguing asymmetric control in non-Hermitian systems due to the degeneracy of eigenstates. Here, we present a general method that extends this specific asymmetric response of EP photonic systems to address any arbitrary fully-polarized light. By rotating the meta-structures at EP, Pancharatnam-Berry (PB) phase can be exclusively encoded on one of the circular polarization-conversion channels. To address any arbitrary wavefront, we superpose the optical signals originating from two orthogonally polarized -yet degenerate- EP eigenmodes. The construction of such orthogonal EP eigenstates pairs is achieved by applying mirror-symmetry to the nanostructure geometry flipping thereby the EP eigenmode handedness from left to right circular polarization. Non-Hermitian reflective PB metasurfaces designed using such EP superposition enable arbitrary, yet unidirectional, vectorial wavefront shaping devices. Our results open new avenues for topological wave control and illustrate the capabilities of topological photonics to distinctively operate on arbitrary polarization-state with enhanced performances.

Rice grain yield and quality are negatively impacted by high temperature stress. Irrigation water temperature significantly affects rice growth and development, thus influencing yield and quality. The role of cooler irrigation water in counteracting high temperature induced damages in rice grain yield and quality are not explored. Hence, in the present study two rice hybrids, Liangyoupeijiu (LYPJ) and IIyou 602 (IIY602) were exposed to heat stress and irrigated with water having different temperatures in a split-split plot experimental design. The stress was imposed starting from heading until maturity under field-based heat tents, over two consecutive years. The maximum day temperature inside the heat tents was set at 38 °C. For the irrigation treatments, two different water sources were used including belowground water with cooler water temperature and pond water with relatively higher water temperature. Daytime mean temperatures in the heat tents were increased by 1.2–2.0 °C across two years, while night-time temperature remained similar at both within and outside the heat tents. Cooler belowground water irrigation did have little effect on air temperature at the canopy level but decreased soil temperature (0.2–1.4 °C) especially under control. Heat stress significantly reduced grain yield (33% to 43%), panicles m−2 (9% to 10%), spikelets m−2 (15% to 22%), grain-filling percentage (13% to 26%) and 1000-grain weight (3% to 5%). Heat stress significantly increased chalkiness and protein content and decreased grain length and amylose content. Grain yield was negatively related to air temperature at the canopy level and soil temperature. Whereas grain quality parameters like chalkiness recorded a significantly positive association with both air and soil temperatures. Irrigating with cooler belowground water reduced the negative effect of heat stress on grain yield by 8.8% in LYPJ, while the same effect was not seen in IIY602, indicating cultivar differences in their response to irrigation water temperature. Our findings reveal that irrigating with cooler belowground water would not significantly mitigate yield loss or improve grain quality under realistic field condition. The outcome of this study adds to the scientific knowledge in understanding the interaction between heat stress and irrigation as a mitigation tool. Irrigation water temperature regulation at the rhizosphere was unable to counteract heat stress damages in rice and hence a more integrated management and genetic options at canopy levels should be explored in the future.

Abstract The energy density of commercial lithium (Li) ion batteries with graphite anode is reaching the limit. It is believed that directly utilizing Li metal as anode without a host could enhance the battery’s energy density to the maximum extent. However, the poor reversibility and infinite volume change of Li metal hinder the realistic implementation of Li metal in battery community. Herein, a commercially viable hybrid Li-ion/metal battery is realized by a coordinated strategy of symbiotic anode and prelithiated cathode. To be specific, a scalable template-removal method is developed to fabricate the porous graphite layer (PGL), which acts as a symbiotic host for Li ion intercalation and subsequent Li metal deposition due to the enhanced lithiophilicity and sufficient ion-conducting pathways. A continuous dissolution-deintercalation mechanism during delithiation process further ensures the elimination of dead Li. As a result, when the excess plating Li reaches 30%, the PGL could deliver an ultrahigh average Coulombic efficiency of 99.5% for 180 cycles with a capacity of 2.48 mAh cm−2 in traditional carbonate electrolyte. Meanwhile, an air-stable recrystallized lithium oxalate with high specific capacity (514.3 mAh g−1) and moderate operating potential (4.7–5.0 V) is introduced as a sacrificial cathode to compensate the initial loss and provide Li source for subsequent cycles. Based on the prelithiated cathode and initial Li-free symbiotic anode, under a practical-level 3 mAh capacity, the assembled hybrid Li-ion/metal full cell with a P/N ratio (capacity ratio of LiNi0.8Co0.1Mn0.1O2 to graphite) of 1.3 exhibits significantly improved capacity retention after 300 cycles, indicating its great potential for high-energy-density Li batteries.

Neodymium (Nd)- or yttrium (Y)- modified bulk Ni2P catalysts (Nd-Ni2P or Y-Ni2P) have been successfully prepared and their catalytic performance in benzofuran hydrodeoxygenation have been investigated. The as-prepared catalysts were characterised by X-ray diffraction, N2 adsorption--desorption, CO uptake and X-ray photoelectron spectroscopy. The addition of Nd or Y, especially Nd, can increase the surface area of the catalysts and promote the formation of smaller and more highly dispersed Ni2P particles. The Nd-Ni2P catalyst showed the highest benzofuran hydrodeoxygenation activity of 95.3% and the O-free products yield of 74.6%, which gives an increase of 25.3% and 35.4% when compared with that found for Ni2P. [ABSTRACT FROM AUTHOR]

In recent years, lots of efforts have been applied to improve the initial Coulombic efficiency (ICE) of lithium-ion batteries (LIBs), among which prelithiation is considered to be one of the most promising schemes. Here we report a modified LixSi with high lithium reserves and great environmental adaptability as the prelithiation reagent, which can make up for the capacity loss of the negative electrode in the first cycle. Through the chemical reaction between aluminum isopropoxide and LixSi, a protective layer consisting of LixAlySiOz/Li2O is formed on the surface of LixSi particles. This synthesized material provides a new idea for the actual industrial production of prelithiation.