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Efficient Trichromatic Ultralong Persistent Luminescence Activated by Body Temperature Toward Convenient Information Encryption and Storage
ABSTRACT Long‐persistent luminescence (LPL) materials, celebrated for their remarkable ability to capture and gradually release light over extended durations, have catalyzed advances in domains such as optical data storage and bioimaging. However, the synthesis of efficient, multicolor ultralong LPL with precise modulation of duration remains a formidable challenge. Here, we introduce an effective strategy for inducing trichromatic ultralong LPL in Cs 2 NaScCl 6 :Sb 3+ through meticulous defect engineering. By judiciously adjusting the dosage of hydrochloric acid during synthesis, we systematically regulate the formation of Na + and Cl − vacancies as well as Sb 3+ ‐induced lattice distortions, affording unprecedented control over the material's luminescent properties. This approach culminates in the achievement of a record‐breaking blue afterglow exceeding 30 h for naked eye, alongside green and red persisting for 48 and 24 h, respectively. Notably, the dual self‐trapped exciton (STE) emissions exhibit disparate thermal behaviors, with the higher‐energy STE demonstrating anti‐thermal quenching, while the lower‐energy counterpart undergoes typical thermal quenching. For the first time, we elucidate the activation of LPL via body temperature, enabling information retrieval through tactile interaction. This innovative material showcases profound potential for x‐ray imaging and secure data encoding, offering a novel avenue for the development of advanced LPL materials with finely tuned emission characteristics.
Unraveling Bridging‐Oxygen‐Driven Ultrafast Amorphization in Superionic Oxyhalide Conductors via in Situ Synchrotron X‐Ray Scattering
ABSTRACT The energy‐ and time‐consuming mechanochemical synthesis of high‐performance solid electrolytes (SEs) remains a critical bottleneck for the scaling of all‐solid‐state batteries. Despite the recognition that oxygen incorporation in structure serves as a viable strategy to develop high‐performance halide SEs, systematic investigations into how oxygen in structure modulates synthesis kinetics, local structure, and ion transport are scarce. Herein, we report the synthesis of amorphous oxyhalide NaTaOCl 4 as a model system, achieved via minute‐scale ball milling, a dramatic improvement over the multi‐day synthesis of conventional NaTaCl 6 . Complementary structural characterizations and ab initio molecular dynamics (AIMD) simulations demonstrate that, low‐coordinated bridging‐oxygen‐dominated Ta−O−Cl environments induce substantial lattice distortions, enabling ultrafast amorphization. Time‐resolved in situ synchrotron x‐ray scattering experiments reveal distinct reaction pathways: NaTaOCl 4 undergoes rapid fragmentation of precursors into metastable intermediates followed by bridging‐oxygen‐driven amorphous formation, whereas NaTaCl 6 experiences a moderate crystallization process prior to prolonged amorphization. By extending this design to a series of mixed‑anion oxyhalides, we establish a universal rapid synthesis strategy. For instance, NaTaO 0.5 Cl 5 exhibits high ionic conductivities of 3.39 mS cm −1 after only 30 min of ball‐milling. This work establishes a strategy that employs oxygen as a structural bridging‐agent to develop high‐conductivity SEs and provides atomic‐scale insights into ultrafast mechanochemical reaction.
From Fiber Bundles to Architected Membranes: Triply Periodic Minimal Surface Architectures for Biohybrid Artificial Lungs
ABSTRACT Artificial lung systems rely almost exclusively on hollow fiber membrane (HFM) bundles, where gas exchange is constrained by heterogeneous flow distribution and thrombogenic blood–material interfaces. Here, we introduce an architecture‐driven design framework for artificial lungs based on additively manufactured triply periodic minimal surface (TPMS) membranes. In contrast to discrete fiber bundles, TPMS membranes form continuous three‐dimensional architectures that simultaneously regulate perfusion pathways, diffusion interfaces, and blood–material interactions. Computational fluid dynamics and multiphysics transport simulations reveal that membrane architecture governs gas exchange through coupled effects of membrane thickness, unit cell size, and three‐dimensional flow topology. Optimized TPMS architectures achieved on average up to ∼88% higher oxygen transfer rates across the investigated flow regime compared to conventional HFM while enabling substantially more homogeneous flow fields and reduced stagnation zones. Experimental screening identifies polydimethylsiloxane‐based printable elastomers compatible with thin gas‐permeable membranes and endothelial functionalization. The biohybrid endothelial interface mitigates thrombogenic interactions, while maintaining gas transport. Computed tomography–derived implant geometries demonstrate the feasibility of translating architected membrane systems into anatomically integrated artificial lungs. Together, these results establish a new design paradigm for artificial lungs, in which membrane architecture becomes the primary determinant of gas transport, flow distribution, and hemocompatibility.
Customizing Axially‐Oriented Dual‐Atomic Synergy for Orchestrating Cascade Alkaline Hydrogen Evolution
ABSTRACT The full orchestration of synergistic geometric and electronic interaction at atomic scale is fundamental to surmounting cascade kinetic bottlenecks inherent in multistep electrochemical processes. Here, an axially‐oriented, sulfur‐bridged hetero‐atomic motif (Ru─S─Co) is customized to achieve synergistic regulation throughout alkaline hydrogen evolution reaction (HER). The top‐positioned Ru atoms are tailored for enhanced water capture, and the bottom‐inserted Co atoms in lattice activate middle S atoms for balanced hydrogen adsorption–desorption. This customized multi‐site synergy conspicuously lowers the energy barrier for rate‐determining water scission step. The proportion of reactive free water is elevated on this modified interface to prompt alkaline HER initiation. Furthermore, the intrinsically asymmetric charge distribution along the dual‐atom bridge enhances charge transfer during HER, and the prominent orbital coupling induces an upshift in the Ru d ‐band center together with increased density of states in S p‐orbitals around the Fermi level, further augmenting Ru‐S dual‐site activity. With this catalyst adopted as cathode, the anion‐exchange‐membrane electrolysis cell maintains an industrial current density of 1000 mA cm −2 at a small voltage of 1.79 V with negligible performance decay after long‐term stability test. This work provides insights into precise customization of atomic‐scale synergy toward effective management of kinetically mismatched multisteps in HER‐related energy conversion.
Ultra‐Fast Mass Transfer System by ∼100% Validated Micro‐Basins for Large‐Scale Photochemical Hydrogen Production
ABSTRACT Achieving large‐scale, efficient, and sustainable hydrogen production via environmentally friendly photocatalysis requires not only effective mass transfer but also excellent operational stability. Conventional particulate photocatalyst systems suffer from inherent limitations in mass transfer, such as disordered charge carrier migration and uncontrolled gas bubble evolution, which collectively hinder hydrogen production efficiency. Here, we present a new mass transfer strategy for large‐scale photochemical hydrogen production, which effectively overcomes intrinsic transport limitations and enables ultra‐fast hydrogen bubble detachment by a coalescence‐induced jumping mechanism. By rationally designing a tunnel‐junction photochemical diode integrated with a micro‐basin array of metallic cocatalysts, we achieved nearly 100% activation of surface catalytic sites, thereby promoting directional charge carrier transport and rapid gas bubble evolution. This design delivers an impressive hydrogen production rate of 177.53 µmol h −1 cm −2 and an apparent quantum yield of 70.7% under 420 nm illumination. An outdoor solar‐driven photocatalytic reactor (25 cm × 25 cm) with a high hydrogen production rate was successfully demonstrated, validating the performance of a full‐scale photocatalyst system. This work demonstrates a large‐scale GaN‐based photochemical hydrogen‐production system and provides a useful structural design strategy for the future development of solar hydrogen‐generation technologies.
An E‐interwoven Therapeutic Contact Lens System for Rapid Drug Delivery and Precision Dose Monitoring
ABSTRACT Precise intraocular pressure (IOP) management and rapid intervention preserve glaucoma vision, yet current ocular delivery systems lack in situ dosage verification, causing treatment blind spots. Here, we develop a wireless therapeutic smart contact lens (SCL) containing a rapid voltage‐triggered drug delivery system with a real‐time dosage monitoring sensor. The e‐interwoven design integrates drug delivery and sensing electrodes in an ultra‐thin (17.4 µm) tri‐interdigital configuration, which enables the electric field to interact with the drug‐loaded hydrogel in the same spatial region. A frequency‐matching strategy boosts voltage coupling to drive a brimonidine tartrate‐loaded hydrogel to achieve high concentrations in the aqueous humor in 20 min, significantly faster than topical eye drops. The built‐in drug dose sensor has a high accuracy <2.8 µg, benefiting from the great linear correlation between wireless frequency drift and release dosage. In acute glaucoma rabbit models, this SCL suppresses peak IOP elevation by 85.7% compared to eye drops. This SCL presents a highly integrated therapeutic platform demonstrating potential for rapid and precise glaucoma treatment.
Hydrogen Spillover by Synergy at Ir─O─Ru Interfaces for Ampere‐Level Hydrogen Evolution
ABSTRACT Industrial‐scale hydrogen production via alkaline water electrolysis requires electrocatalysts capable of sustaining ampere‐level current densities, yet the sluggish Volmer step remains a fundamental kinetic bottleneck. In this study, we report a surface‐microenvironment engineered catalyst in which atomically dispersed iridium atoms are selectively decorated on ruthenium nanoparticles through coordination with surface ─OH groups and defect oxygen sites, forming electronically coupled Ir─O─Ru interfacial ensembles. Density functional theory calculations based on the Ir─O─Ru interfacial model reveal a cooperative hydrogen‐spillover mechanism, in which the positively polarized Ir─O microenvironment promotes H 2 O activation, while the electronically tuned adjacent Ru sites accommodate the spilled‐over H* and drive the H─H coupling, thereby reducing the rate‐determining barrier to 0.19 eV. As a result, the catalyst achieves 1.0 A cm −2 at an overpotential of 103 mV in 1.0 M KOH and shows outstanding durability (3038 h at 1.0 A cm −2 ; 1593 h at 2.0 A cm −2 ). It further maintains stable operation in alkaline seawater (1427 h at 1.0 A cm −2 ) and anion‐exchange‐membrane electrolyzer (910 h at 80°C). These findings demonstrate that single‐atom surface decoration can effectively reconfigure interfacial reaction pathways, providing an efficient strategy for high‐flux alkaline hydrogen evolution.
Triboron Multiresonant Emitter With Zigzag B/N Alignment Enables Near‐Degenerate Singlet–Triplet States for High‐Performance Non‐Sensitized OLEDs With Mild Roll‐Off
ABSTRACT Boron/nitrogen‐embedded polycyclic frameworks are attractive emitters in organic light‐emitting diodes (OLEDs) because they combine narrowband emission with thermally activated delayed fluorescence. Linear extension of multiresonant frameworks with zigzag boron/nitrogen alignment is predicted to enable bathochromic emission, reduced singlet–triplet energy gaps, and enhanced oscillator strengths, yet experimental access to higher‐order structures remains challenging. Here we report a site‐programmable, stepwise borylation strategy for constructing a triboron DABNA‐extended framework with zigzag boron/nitrogen alignment, L‐DABNA‐TriB. Our combined theoretical and experimental studies reveal how progressive linear extension from mono‐ to tri‐boron frameworks modulates the electronic structure, leading to bandgap narrowing, strengthened radiative transition, and near‐degenerate singlet and triplet excited states. Importantly, L‐DABNA‐TriB in toluene exhibits yellow–orange emission at 559 nm with a narrow full width at half‐maximum of 33 nm/0.13 eV, a singlet–triplet energy gap of ca. 4 meV, and a radiative decay rate of 1.5 × 10 8 s −1 . A non‐sensitized OLED based on L ‐DABNA‐TriB achieves a maximum external quantum efficiency of 38.0% and retains 35.2% at 1000 cd m −2 . This work establishes zigzag boron/nitrogen‐aligned linear extension as an effective molecular design strategy for narrowband emitters with efficient exciton harvesting at long wavelengths.
Auxin‐Functionalized Nanocarriers Hijack Endogenous Transport for Systemic Crop Protection in Plants
ABSTRACT Precise delivery of functional agents to specific plant organs remains a central challenge, as synthetic materials rarely access endogenous long‐distance transport pathways. Here, we report an auxin‐functionalized nanocarrier strategy that enables programmable systemic transport by interfacing engineered materials with plant signaling networks. Nanocarrier dimensions were tuned to ∼55 nm to limit endocytosis and favor extracellular localization, while auxin motifs were introduced on the particle surface. This design establishes a predominantly extracellular interface that hijacks polar auxin transport pathways. As a result, PIN‐mediated fluxes are enhanced, accompanied by a 10.42‐fold upregulation of PIN1, enabling directional leaf‐to‐root transport over centimeter scales and a 72.32‐fold increase in root accumulation. This signal‐coupled transport mechanism enables efficient root‐targeted delivery of agrochemical cargos (abamectin) via foliar application, achieving up to 79.71% control of root‐knot nematodes while reducing pesticide input by half. Furthermore, bypassing soil application provides a 3.20‐fold higher ecological safety margin and yields a 16.47% increase in crop production. Beyond this application, the work establishes a generalizable design principle in which synthetic materials exploit endogenous signaling frameworks to navigate biological transport systems, opening new opportunities for systemic crop protection and bio‐integrated material delivery.
Dual‐Peak Friction Upon Traversing a Monolithic Subsurface Step in Layered Materials
ABSTRACT High‐resolution atomic force microscopy (AFM) measurements reveal a distinctive anomalous dual‐peak feature emerges in friction force when the tip scans across a well‐defined monolithic step covered by few‐layer 2D materials, deviating fundamentally from the conventional single‐peak expected for a simple topographic obstacle. Through systematic high‐resolution stick‐slip measurements, nanoindentation experiments, and molecular dynamics (MD) simulations, this bifurcated frictional response is attributed to the asynchronous evolution of the resistive and driving force as the tip becomes transiently pinned first at the front and then at the rear of the step. The dual‐peak friction mechanism provides new perspectives for addressing inevitable step‐related challenges in 2D material lubrication systems, which is essential for elucidating the frictional origins of structural superlubricity in devices.
Deterministic magnetization switching by giant orbital torque in perpendicularly magnetized V/Pt/Co heterostructures
Spin–Orbit Torque Magnetic Random-Access Memory is a next-generation memory technology. Its conventional switching scheme relies on the spin Hall effect to switch the magnetization of the free layer. However, this approach depends mostly on the materials with strong spin–orbit coupling (SOC). In contrast, the orbital Hall effect offers an alternative pathway that can be efficiently generated even in light materials with weak SOC, e.g., Zr, Nb, and Cr, thereby expanding the range of materials available for energy-efficient magnetization switching. By integrating perpendicularly magnetized Co with the transition metal vanadium (V) in V/Pt/Co heterostructures, this study experimentally discovers a giant orbital Hall angle of 0.71 in V, reducing the critical switching current density (Jc) to 15.5 MA/cm2, a 78.5% decrease compared to conventional Pt-based systems. More importantly, the heterostructure maintains a relatively large coercivity (Hc) of 126 Oe, which indicates a high magnetic anisotropy (Ku) and therefore leads to a high thermal stability factor (Δ). The combination of high orbital torque efficiency, low Jc, and exceptional thermal stability establishes a new material platform for reliable, energy-efficient orbitronic memory applications.
Toughened Hybrid Electron‐Transporting Interlayers for Efficient and Durable Organic Solar Cells
ABSTRACT Electron‐transporting layers (ETLs) are crucial in determining the performance of organic solar cells (OSCs). However, it is challenging to achieve desired efficiency and stability simultaneously for devices based on single‐component ETLs. Here, we demonstrate the application of polyoxometalate (POM)‐doped hybrid ETLs to achieve significantly mitigated efficiency‐stability trade‐off in OSCs. By tailoring the doping behaviors, hybrid ETLs exhibit cascade energy‐level alignment, increased conductivity, improved electrode adhesion, strong thickness tolerance, and suppressed self‐aggregation. These combined merits enable excellent efficiency (20.4%) and outstanding stability (a T 93 / T 92 lifetime of 1500/1000 h under MPP tracking at 40°C/65°C) to be achieved for OSCs. A further elevated efficiency of 20.8% (20.4%, certified) and a T 90 lifetime of 1000 h can also be achieved when PDIN‐EME is used as the new organic component in the hybrid ETL, demonstrating the easy tunability of these hybrid interlayers for more efficient and robust OSCs.
Green LEDs with V-defects formed from intentional dislocation half-loops
Group III-nitride light emitting diodes (LEDs) suffer from poor efficiency for longer wavelength emission. This is partly due to increased polarization-induced barriers to vertical carrier injection at InGaN/GaN interfaces in the polar c-plane, where higher In-content is required for long-wavelength emission. Polarization-induced barriers can be bypassed by lateral carrier injection through the semipolar sidewalls of V-defects, which form at the apex of threading dislocations (TDs) during kinetically limited growth. This increases wall-plug efficiency (WPE) through the reduction of forward voltage (VF). TD and resulting V-defect density can be controlled through the formation of edge dislocation half-loops prior to V-defect opening. In this work, we demonstrate a green V-defect LED with optimized AlGaN caps with high external quantum efficiency (EQE) and WPE. The green V-defect LED demonstrated here with such a device structure achieves a peak EQE and a peak WPE of 43.9% and 37.0%, respectively.
Fluorine‐Rich Catalyst‐Induced Interphase Engineering to Enable the First Ah‐Level FeF <sub>3</sub> Conversion Solid‐State Batteries
ABSTRACT Conversion‐type FeF 3 cathodes promise ultrahigh energy density but suffer from sluggish reaction kinetics and interfacial instability in solid‐state battery systems. Here, we designed a fluorine‐rich NaBiF 4 @Bi 2 O 3 catalyst‐initiated polymer electrolyte via in situ ring‐opening polymerization of 1,3‐dioxolane. The NaBiF 4 phase initiates polymerization and serves as a fluorine reservoir, while Bi 2 O 3 participates in regulating the fluorine environment and contributes to the formation of a Li 3 Bi alloy clusters during cycling. This electrolyte enables the construction of LiF/NaF/Li 2 O‐reinforced solid electrolyte interface with embedded Li 3 Bi domains, delivering the homogeneous Li + flux and dendrite‐free Li deposition, enabling the stable Li‖Li symmetric cell cycling for 9700 h. The electrolyte demonstrates broad compatibility with both intercalation and conversion cathodes, achieving excellent cycling stability (800 cycles) in LiFePO 4 and high areal capacity (6 mAh cm −2 ) in LiNi 0.8 Co 0.1 Mn 0.1 O 2 . The Bi 2 O 3 component further catalyzes the interfacial dissociation of LiF at FeF 3 cathode and promotes the dynamic evolution of fluorine‐rich cathode electrolyte interphase, enabling the remarkable reversibility in FeF 3 conversion chemistry (641 mAh g −1 at 0.2 C and 300 cycles at 1 C). A 20‐layer FeF 3 ‐based pouch cell is demonstrated with a discharge capacity exceeding 1 Ah for the first time, marking a critical milestone toward practical high‐energy FeF 3 batteries.
Thermally tunable high-voltage breakdown and divergent avalanche nonlinearity in planar SnO2 nanofilm varistors
We present a planar, dopant-segregation-free SnO2 nanofilm varistor on a polycrystalline Al2O3 substrate that achieves a kilovolt-level breakdown voltage (V1 mA ≈ 759 V at 300 K). By directing the conduction pathway laterally across approximately 200 grain boundaries in series, this architecture overcomes the low-voltage limitations of conventional vertical thin films. Within the compliance-limited window, the device exhibits a pronounced divergent nonlinearity without bulk-resistance rollover. This steep current rise is analytically identified as an avalanche-type divergence, α(V)=V/(V*−V), driven by an electro-thermally assisted barrier collapse under localized Joule heating. To capture the full I–V trajectory across 200–500 K, we formulate a cascade model employing logistic soft-switch weights to govern the competitive transitions among Ohmic leakage, thermionic emission, and avalanche multiplication. The critical divergence voltage V* follows a strict Arrhenius scaling with an effective activation energy of ∼33 meV, reflecting how ambient thermal energy exponentially accelerates the pre-breakdown conductivity to reach the thermal runaway threshold. This planar nanofilm provides a lithographically defined, circuit-compatible platform, complementary to bulk ceramics, for on-chip transient voltage suppression.
Triboelectric E‐Skin for Robotic Perception of Hazardous Chemical Leaks
ABSTRACT The rapid identification of chemical composition, temperature, and dynamic behavior of leaked liquids by robots during accidental spills of hazardous chemicals would significantly reduce the potential risks to both human health and the environment. Here, we designed a flexible, palm‐shaped liquid‐sensing e‐skin (PSLSES) featuring 128 metal electrodes fabricated via flexible printed circuit (FPC) technology and coated with a fluorinated ethylene propylene (FEP) film. By capturing the local triboelectrification signals along the droplet's trajectory, PSLSES enables multimodal dynamic liquid sensing, simultaneously achieving liquid composition identification, temperature sensing, as well as droplet motion tracking through visualized trajectory patterns. Integrated with a one‐dimensional convolutional neural network (1D CNN), PSLSES achieves an ultrahigh identification accuracy of 99.5% across 21 types of liquids, with a high monitoring resolution down to the ppb level and 98% accuracy in identifying liquid temperature. This includes deionized water, acids, bases, salts, and organic solutions, demonstrating broad liquid identification versatility. Compared with previously reported E‐skin systems, it achieved faster identification (0.3 s), a lower detection limit (0.1 ppb), broader liquid recognition, and higher accuracy. The integration of PSLSES into wearable robotics systems opens new ways for robots to assist humans in analyzing and handling chemical leakage in hazardous environments.
A reconfigurable, broadband light-field mapper for illusionary effects
The manipulation of light field is pivotal for advancing optical technologies. Here, we present a reconfigurable optical system based on lens-fiber networks that function as a light-field mapper, capable of generating macroscopic optical illusions. This system employs a lens array to decompose the incident light field, which is then transmitted via a fiber network and reconstructed by a second lens array. This process establishes a reconfigurable mapping between input and output light fields. Through proof-of-principle experiments, we demonstrate “free-space” illusion devices, where light rays traverse the mapper—including embedded opaque objects—in straight lines, effectively mimicking propagation through free space. Our work introduces a flexible platform for light-field manipulation with potential applications in virtual reality, optical computing, and secure communication.
Microwave-photonic control of optically accessible spin defects in diamond
A growing variety of optically accessible spin qubits have emerged in recent years as key components for quantum sensors, computers, and memories. However, the scalability of conventional spin-based quantum architectures remains limited by direct microwave delivery, which introduces thermal noise, electromagnetic crosstalk, and design constraints for cryogenic, high-field, and distributed systems. In this work, we present a unified framework for RF-over-fiber (RFoF) control of spins accessible through optically detected magnetic resonance (ODMR) spectroscopy of nitrogen-vacancy (NV) centers in diamond. The RFoF platform relies on an intensity-modulated 1310 nm laser carrying microwave signals over fiber and a high-speed photodiode for optical-to-electrical conversion to drive NV spin transitions. We report an RFoF power-conversion efficiency of 3.42% for an RF output PRF,out=−5.5 dBm at 2.87 GHz, enabling clear resolution of Zeeman splitting in proportion to an applied magnetic field. The RFoF architecture provides a path toward low-noise, thermally isolated, and cryo-compatible ODMR systems at sub-THz frequencies, thus bridging conventional spin-based quantum sensing protocols with emerging distributed quantum technologies.
Physical reservoir computing using all-solid-state LaZrO/InO electric double-layer thin-film transistor
Machine-learning-based AI prediction drives rising electricity use and processing demands, raising sustainability concerns. Reservoir computing reduces training by optimizing only output weights, and physical reservoir computing (PRC) further accelerates processing by exploiting physical phenomena. Yet, many hysteresis-based PRCs depend on costly or unstable materials and fabrication methods unsuited to scale, limiting practical deployment. This study evaluated the potential of all-solid-state electric double-layer (EDL) thin-film transistors, incorporating a lanthanum zirconium oxide solid electrolyte and an indium oxide semiconductor, for PRC applications. The drain current (ID) and gate current (IG) as functions of gate voltage (VG) displayed pronounced hysteresis, with the extent of hysteresis dependent on both the drain voltage (VD) and the VG scanning rate. The ID response to pulsed VG inputs demonstrated a clear dependence on the preceding input pulse VG, thereby validating the device's short-term memory properties. In the second-order nonlinear autoregressive moving average task, the minimum normalized mean square error (NMSE) was 7.71 × 10−3 and 7.56 × 10−3 when utilizing the IG response as virtual nodes comprising 40 and 80 points, respectively. Furthermore, the NMSE demonstrated a strong correlation with memory capacity, particularly with the coefficient of determination associated with the correlation for up to two previous data points. The all-solid-state EDL-TFT-based physical reservoir, with its miniaturization, air stability, and broad pulse operating range, offers a scalable and robust platform that could enable practical integration of PRC into next-generation AI devices, advancing energy-efficient and durable hardware solutions.
An engineered metal-to-insulator transition in a two-dimensional network of degenerate phosphorus quantum dots in silicon
Phosphorus quantum dots (QDs) in silicon are a prominent candidate for semiconductor quantum computing based on donor spins. In this work, we report the formation of degenerate phosphorus QDs with a radius of 3 nm confined in a two-dimensional plane in silicon. A multilayer of SiO2/POx/SiO2 on Si substrate is first deposited by atomic layer deposition, which serves as the capping layer, doping source, and doping mask. Defective channels in the SiO2 doping mask layer are then created by random argon (Ar) ion implantation. Finally, phosphorus dopants from the doping source layer, driven by pulsed laser annealing, diffuse through the defective channels in SiO2 into Si substrate, forming phosphorus QDs confined in a two-dimensional (2D) plane near the Si surface. By reducing the Ar dose, we observe a sharp metal-to-insulator transition (MIT) in the resulting 2D electron system. Based on the MIT model for quantum dots, we find that each Ar ion implantation has a chance of only 6.4%–8.1% to create a phosphorus quantum dot.