Kenan Zhang

The downscaling of silicon field-effect transistors is approaching fundamental limits, with the international roadmap for devices and systems (IRDS) projecting a 12 nm channel length plateau by 2037. Two-dimensional (2D) semiconductors have emerged as promising candidates for extended transistor scaling. However, no experimental demonstration has thus far surpassed the fundamental switching limits of advanced silicon. Here, we report monolayer MoS₂ transistors with physical channel lengths below 5 nm, achieving a subthreshold swing of 88 mV/dec and an on/off ratio above 10⁶. These results surpass both the theoretical subthreshold limit of silicon and state-of-the-art emerging semiconductors-based transistors at comparable dimensions. To ensure high throughput, we develop a photolithography based, complementary metal oxide semiconductor (CMOS) compatible process and demonstrate 4-inch wafer-scale integration. We implement a design–technology co-optimization approach featuring an air-gap isolation and gate-contact overlap design to effectively suppress short channel effects. This work demonstrates subthreshold transport in a 2D semiconductor transistor beyond the silicon limit, showing a viable pathway for extending transistor scaling and energy-efficient computing.

Lattice and microstructural phases are always critical for controlling optical, electronic, and optoelectronic characterizations of semiconductor materials and their functional devices. Gallium oxide (Ga ₂ O ₃ ) is widely recognized as a promising material for solar‐blind ultraviolet photodetectors, with both amorphous and crystalline phases offering distinct advantages. Nevertheless, inherent crystallinity issues still hinder device performance and practical application. In this work, we systematically investigated the correlation between microstructure and dynamic evolution of photogenerated carriers in Ga ₂ O ₃ via crystal phase manipulation. High‐performance nanocrystalline Ga ₂ O ₃ photodetectors were demonstrated with a high detectivity of 3.50 × 10 ¹³ Jones and a larger photo‐to‐dark current ratio up to 5.56 × 10 ⁴ . Related photoresponsivity and rejection ratio of the ultraviolet photodetectors were significantly modulated by amorphous, nanocrystalline, and multicrystalline microstructural phases. This modulation is attributed to oxygen‐vacancy‐related defects, which introduce additional energy levels acting as electron donors that significantly alter the carrier concentration and thus regulate the signal intensity of the photoresponse. These insights underscore the critical role of structural phase engineering in Ga ₂ O ₃ and provide valuable guidance for the design and optimization of high‐performance solar‐blind ultraviolet photodetectors.

Establishing an electrical readout of antiferromagnetic (AFM) spin order in low-dimensional materials remains a fundamental challenge. Here, we demonstrate a direct optoelectronic probe of AFM order in layered FePS3 using polarization-resolved reflectance and photocurrent measurements. Below the Néel temperature (TN), FePS3 exhibits pronounced in-plane optical anisotropy and a strongly polarization-dependent photocurrent response, whereas the photocurrent becomes nearly isotropic in the paramagnetic phase. Notably, the polarization-dependent photocurrent is closely correlated with the zigzag AFM spin configuration, highlighting the role of spin–charge light-field coupling in FePS3. Furthermore, the devices exhibit ultrahigh signal-to-noise ratios exceeding 103 at low temperatures and ultrafast photoresponse (∼2.6 μs) at room temperature. These findings establish polarization-resolved photocurrent as a practical electrical probe of AFM order and highlight its potential for exploring spin-texture-related phenomena in two-dimensional antiferromagnets.

Intrinsic defects in two-dimensional (2D) atomic crystals impose severe constraints on carrier utilization through defect-induced trapping and recombination. While surface modification and mobility recovery strategies have been widely explored, the development of a universal defect mitigation protocol remains unresolved. Here, we introduce a molecular passivation strategy in which Taxol molecules, via their hydroxyl radicals, repair intrinsic sulfur vacancies in monolayer MoS2, thereby markedly accelerating carrier transport dynamics. The Taxol framework not only modulates the electronic structure of n-type MoS2 lattices but also shows compatibility with p-type MoS2 configurations, enabling robust interfacial unit cell binding. Following modification, both n- and p-type MoS2 exhibit acoustic phonon-limited mobilities enhanced and more than an order of magnitude for p-type conuterpart. This universal lattice-reconstruction strategy further suppresses noise power by up to six orders of magnitude and restrain interface state, while achieving a responsivity above 200 A W−1 and specific detectivity exceeding 1.0 × 1012 Jones — representing an improvement of four orders of magnitude. Complementary theoretical calculations confirm that Taxol-mediated coordination effectively passivates sulfur vacancies and optimizes charge transport. These findings establish a universal molecular coordination protocol to mitigate defect-related noise currents and boost detection sensitivity, advancing the performance of 2D photodetectors for next-generation optoelectronic and biosensing applications.

Van der Waals (vdW) materials offer unique opportunities for 3D integration^1,2 of planar circuits towards higher-density transistors and energy-efficient computation^3,4,5,6,7. Owing to the high thermal budget and special substrate requirement for the synthesis of high-quality vdW materials^8,9,10, an advanced transfer technique is required that can simultaneously meet a broad range of industrial requirements, including high intactness, cleanliness and speed, large scale, low cost and versatility. However, previous efforts based on either etching or etching-free mechanisms typically only improve one or two of the aforementioned aspects^11,12,13 and a comprehensive and systematic solution remains lacking. Here we demonstrate an electrostatic-repulsion-enabled advanced transfer technique that is etching free, high yield, fast, wafer scale, low cost and widely applicable, using ammonia solution compatible with the complementary metal–oxide–semiconductor (CMOS) industry. The high material intactness and interface cleanliness enable superior device performances in 2D field-effect transistors with 100% yield, near-zero hysteresis (7 mV) and near-ideal subthreshold swing (65.9 mV dec⁻¹). The combination with bismuth contact further enables an ultrahigh on-current of 1.3 mA μm⁻¹ under 1 V bias. This advanced transfer approach offers a facile and manufacturing-viable solution for vdW-materials-based electronics, paving the way for advanced 3D integration in the future.

Two-dimensional (2D) semiconductors hold great promise for future electronics, yet the fabrication of clean ohmic electrical contacts remains a key challenge. Traditional lithography and metallization processes often introduce interfacial disorder, and recently developed electrode-transfer-based techniques are difficult to implement without contaminating the interfaces between 2D crystals and metals. Here, we demonstrate a low-temperature chemical vapor deposition (CVD)-based van der Waals (vdW) epitaxy method to grow 2D metal (Cd) electrodes, eliminating lithography, deposition, or transfer processes and enabling the damage-free integration of 2D semiconductors. This thermodynamic integration strategy significantly mitigates the interfacial disorder and metal-induced gap states (MIGS), leading to low contact resistance (R_C) and near-zero barrier ohmic contacts. Cd-MoS₂ field-effect transistors (FETs) exhibit R_C down to 70–100 Ω·μm, on-state current densities up to 942 μA/μm, on/off ratios exceeding 10⁸, and mobilities up to 160 cm² V⁻¹ s⁻¹. These results position vdW epitaxially grown 2D metals as a promising contact technology for next-generation electronics beyond silicon.