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The primary challenge facing silicon-based electronics, crucial for modern technological progress, is difficulty in dimensional scaling. This stems from a severe deterioration of transistor performance due to carrier scattering when silicon thickness is reduced below a few nanometres. Atomically thin two-dimensional (2D) semiconductors still maintain their electrical characteristics even at sub-nanometre scales and offer the potential for monolithic three-dimensional (3D) integration. Here we explore a strategic shift aimed at addressing the scaling bottleneck of silicon by adopting 2D semiconductors as new channel materials. Examining both academic and industrial viewpoints, we delve into the latest trends in channel materials, the integration of metal contacts and gate dielectrics, and offer insights into the emerging landscape of industrializing 2D semiconductor-based transistors for monolithic 3D integration. This Review explores adopting 2D semiconductors to overcome the scaling bottleneck of Si-based electronics. Recent trends and potential approaches for the development of 2D materials as a channel are discussed. Following this, the prerequisites, obstacles and feasible technologies for integrating contacts and gate dielectrics with 2D semiconductor-based channels are examined. The Review also provides an industrial perspective towards facilitating monolithic 3D integration.

Rapid development of vaccines and therapeutics is necessary to tackle the emergence of new pathogens and infectious diseases. To speed up the drug discovery process, the conventional development pipeline can be retooled by introducing advanced in vitro models as alternatives to conventional infectious disease models and by employing advanced technology for the production of medicine and cell/drug delivery systems. In this regard, layer-by-layer construction with a 3D bioprinting system or other technologies provides a beneficial method for developing highly biomimetic and reliable in vitro models for infectious disease research. In addition, the high flexibility and versatility of 3D bioprinting offer advantages in the effective production of vaccines, therapeutics, and relevant delivery systems. Herein, we discuss the potential of 3D bioprinting technologies for the control of infectious diseases. We also suggest that 3D bioprinting in infectious disease research and drug development could be a significant platform technology for the rapid and automated production of tissue/organ models and medicines in the near future.

Chiroptoelectronic devices are crucial for applications in quantum computing, spin optical communications, and magnetic recording. However, the limited efficiency and low stability of conventional circularly polarized light (CPL)-sensing materials have restricted their broader use. Here, we introduce atomic chiral Se nanorod (NRs) films as broadband CPL detectors, leveraging the intrinsic chirality and stability of Se nanocrystals. We also perform incident circular polarization (ICP)-Raman optical activity (ROA) to explore the chiroptical activity of the large-area films. The Se NRs thin films detected CPL across a broad range from ultraviolet (UV) to short-wavelength infrared (SWIR), with a responsivity dissymmetry factor of up to 0.4, maintaining high stability under ambient conditions for longer than 13 months. CPL-sensitive Se NRs with intrinsic chirality have potential applications in chiral photonic synapses, chiral spin devices, and CPL-sensitive photocatalysts. ICP-ROA mapping also advances the analysis of 2D chiral materials. Conventional circularly polarized light (CPL)-sensing materials are usually limited by low efficiency and/or stability. Here, the authors report the realization of broadband CPL detectors based on chiral Se nanorod films with responsivity dissymmetry factor of up to 0.4 and environmental stability for over a year.

Atomically precise fabrication methods are critical for the development of next-generation technologies. For example, in nanoelectronics based on van der Waals heterostructures, where two-dimensional materials are stacked to form devices with nanometer thicknesses, a major challenge is patterning with atomic precision and individually addressing each molecular layer. Here we demonstrate an atomically thin graphene etch stop for patterning van der Waals heterostructures through the selective etch of two-dimensional materials with xenon difluoride gas. Graphene etch stops enable one-step patterning of sophisticated devices from heterostructures by accessing buried layers and forming one-dimensional contacts. Graphene transistors with fluorinated graphene contacts show a room temperature mobility of 40,000 cm 2  V −1  s −1 at carrier density of 4 × 10 12  cm −2 and contact resistivity of 80 Ω·μm. We demonstrate the versatility of graphene etch stops with three-dimensionally integrated nanoelectronics with multiple active layers and nanoelectromechanical devices with performance comparable to the state-of-the-art. Fabrication methods to pattern thin materials are a critical tool to build molecular scale devices. Here the authors report a selective etching method using XeF 2 gas to pattern graphene based heterostructures with multiple active layers and achieve 1D contacts with low contact resistivity of 80 Ω·µm

Two-dimensional semiconductors are an attractive material for making thin-film transistors due to their scalability, transferability, atomic thickness and relatively high carrier mobility. There is, however, a gap in performance between single-device demonstrations, which typically use single-crystalline two-dimensional films, and devices that can be integrated on a large scale using industrial methods. Here we report the 200-mm-wafer-scale integration of polycrystalline molybdenum disulfide (MoS 2 ) field-effect transistors. Our processes are compatible with industry, with processing performed in a commercial 200 mm fabrication facility with a yield of over 99.9%. We find that the metal–semiconductor junction in polycrystalline MoS 2 is fundamentally different from its single-crystalline counterpart, and therefore, we redesign the process flow to nearly eliminate the Schottky barrier height at the metal–MoS 2 contact. The resulting MoS 2 field-effect transistors exhibit mobilities of 21 cm 2  V −1  s −1 , contact resistances of 3.8 kΩ µm and on-current densities of 120 µA µm −1 , which are similar to those achieved with single-crystalline flakes. A method for integrating polycrystalline molybdenum disulfide using processes in a 200 mm fab facility can create transistors with high robustness and performance comparable with single-crystalline devices.

Chirality, the property whereby an object or a system cannot be superimposed on its mirror image, prevails amongst nature over various scales. Especially in biology, numerous chiral building blocks and chiral-specific interactions are involved in many essential biological activities. Despite the prevalence of chirality in nature, it has been no longer than 70 years since the mechanisms of chiral-specific interactions drew scientific attention and began to be studied. Owing to the advent of chiral-sensitive equipment such as circular dichroism spectrometers or chiral liquid columns for chromatography, it has recently been possible to achieve a deeper understanding of the chiral-specific interactions and consequential impacts on the functionality and efficiency of nanomedicine. From this point of view, it is worthwhile to examine previously reported chiral biomaterials with their compositions and possible applications to achieve new paradigms of biomaterials. This review discusses chiral materials on various scales and their biological applications.

Chirality refers to a structure that lacks mirror symmetry. It can be observed in a wide range of platforms, from subatomic particles and molecules to living organisms. However, the underlying mechanisms that give rise to chirality in condensed matter systems have been a subject of considerable interest. Here we elucidate the mechanism of chiral charge density wave formation in the transition-metal dichalcogenide 1T-TiSe 2 . Based on symmetry analysis, we demonstrate that charge density modulations and ionic displacements follow distinct irreducible representations of the space group, despite exhibiting similar wave vectors and a strong coupling. This charge-lattice symmetry frustration induces lattice distortions that further break all symmetries that are not common to both sectors. This ultimately gives rise to chirality. Our theory is verified using Raman spectroscopy and inelastic X-ray scattering. The mechanism of chiral symmetry breaking in condensed matter systems is not well understood. Now charge-lattice symmetry frustration has been shown to be a key factor governing chirality in a charge density wave of 1T-TiSe 2 .

Two-dimensional (2D) semiconductors, such as transition metal dichalcogenides (TMDs) and black phosphorus, are the most promising channel materials for future electronics because of their unique electrical properties. Even though a number of 2D-materials-based logic devices have been demonstrated to date, most of them are a combination of more than two unit devices. If logic devices can be realized in a single channel, it would be advantageous for higher integration and functionality. In this study we report high-performance van der Waals heterostructure (vdW) ReS 2 transistors with graphene electrodes on atomically flat hBN, and demonstrate a NAND gate comprising a single ReS 2 transistor with split gates. Highly sensitive electrostatic doping of ReS 2 enables fabrication of gate-tunable NAND logic gates, which cannot be achieved in bulk semiconductor materials because of the absence of gate tunability. The vdW heterostructure NAND gate comprising a single transistor paves a novel way to realize “all-2D” circuitry for flexible and transparent electronic applications.

Multiplexed cyclic imaging in expandable tissue gels has been extensively studied to visualize numerous biomolecules at a nanoscale resolution in situ. Previous studies have employed sparse labels, such as DAPI or lectin staining, as registration markers. However, these sparse labels do not adequately capture the full extent of deformation across the entire region of interest. To overcome this challenge, we propose the use of dense labels, specifically fluorophore N -hydroxysuccinimide (NHS)-ester staining, as registration markers to achieve highly accurate image registration. We first tested several NHS-functionalized fluorophores as fiducial markers and identified the proper candidates for three-dimensional (3D) multiplexed cyclic imaging. We analyzed the registration accuracy between DAPI and NHS-ester staining and illustrated that dense label-based registration provides a more accurate registration performance. In the multiplexed imaging of expanded specimens, we observed that repetitive expansion/shrinking processes and chemical treatments for signal elimination can induce 3D nonlinear distortion. This sample distortion can be mitigated by re-embedding the tissue gel or replacing the chemical de-staining process with photobleaching-based signal removal or computational signal unmixing. With such an optimized experimental setup, we demonstrated 3D multiplexed cyclic imaging with nanoscale precision image registration. Finally, we prove that dense biological structures, such as actin, can be used as registration markers to achieve high registration accuracy. We anticipate that the proposed dense labeling strategy will overcome the technical limitations of multiplexed cyclic imaging in expandable tissue gels, offering high-precision registration. We expect it to be widely adopted by the biological and medical communities.