Jing Zhang

The low-cost, CMOS-compatible, and lithography-free synthesis of unique silicon fingerprints with encoding capacity up to 2¹⁶³⁸⁴/µm² is reported using metal-assisted chemical etching and low temperature thermal dewetting of metal films. The method provides an optimum 50% coverage of nanostructured silicon, a high level of randomness, and linewidths down to 8 nm, making it resilient against machine learning attacks.

Abstract

The increasing vulnerability of microchips to counterfeiting poses a significant threat to nations, companies, and the general public. Creating a unique “fingerprint” on each chip using intrinsic manufacturing variations can significantly prevent the number of fraudulent chips. Since Si-based semiconductor fabrication processes are now flawless down to a few nanometers, finding a high-entropy source at the nanoscale has become challenging. Inspired by the concept of physical unclonable function, this work reports the CMOS-compatible and lithography-free fabrication of unique nanostructured silicon “fingerprints.” Nanostructuring is achieved via low-temperature dewetting and metal-assisted chemical etching, which produces a high level of entropy and unique silicon-based nanoscale fingerprints with linewidths tunable from ≈8 to 140 nm, commensurate with the dimensions of mainstream microfabrication processes. These Si nanofingerprints are highly reliable for chip authentication and against reverse engineering, providing a large encoding capacity of up to 2¹⁶³⁸⁴/µm². For practical applications, detection of fingerprints protected with a polymer coating is demonstrated using back-scattered electron imaging.

Recent high-performance self-powered photodetectors for infrared bands are mostly made of 2D/3D heterostructures. Here, a 2D/2D van der Waals heterostructure PdSe₂/MoTe₂ is proposed to be a outstanding infrared self-powered detector. It exhibits a self-powered broadband detection from ultraviolet to mid-infrared. Moreover, it possesses a good environmental stability and an infrared imaging capability.

Abstract

Self-powered photodetection is an effective way to resolve the issue of high dark current in infrared photodetectors under a bias voltage. To date, high-performance infrared self-powered photodetectors (ISPDs) are mostly based on heterostructures consisting of 2D and 3D materials, while those based on 2D/2D heterostructures are rare. This will hinder the development of infrared devices toward miniaturization and energy-saving. By exploring some 2D/2D van der Waals (vdWs) heterostructures, constructed by typical 2D transition metal dichalcogenides (TMDs), it is found that the heterostructure PdSe₂/MoTe₂ is a high-performance ISPD. It exhibits a good capability of self-powered broadband detection from 300 to 1550 nm, even extending to 4050 nm. Especially, under near-infrared illumination of 980 nm, its responsivity and detectivity can approach 395 mA W⁻¹ and 1.92 × 10¹¹ Jones, respectively, which can be comparable with the high-performance 2D/3D ISPDs. The heterostructure also possesses good environmental stability and infrared imaging capability. In addition, Three necessary conditions are proposed to construct 2D/2D high-performance ISPD, i.e., a large difference of work function, high infrared absorption, and a type-II band alignment. This work will guide a way to search for excellent ISPDs.

Nature, Published online: 03 February 2025; doi:10.1038/d41586-025-00319-5

So far, microorganisms have been research subjects or contaminants on space stations, but could they assist longer missions?

Nature Nanotechnology, Published online: 03 February 2025; doi:10.1038/s41565-025-01862-y

The work studies the switchable excitonic response in trilayer 3R-MoS2 and shows that the polarization switching pathway in multilayer sliding ferroelectrics results from interactions between domain walls, pinning centres and free-carrier screening.

This study presents the first synthesis of 2D hexagonal Eu₂SO₂ and tetragonal Eu₂SO₆ with tunable dielectric properties. Eu₂SO₂ offers high dielectric performance, while Eu₂SO₆ provides a wider bandgap. Integrated into MoS₂ field-effect transistors, these materials demonstrate excellent performance, highlighting their potential as multifunctional dielectrics for next-generation low-power electronics.

Abstract

Advancing next-generation electronics necessitates precise control of dielectric properties in 2D materials. Here, the first synthesis of novel 2D quasi-van der Waals (vdW) europium oxysulfur (Eu₂SO_x) compounds, comprising hexagonal Eu₂SO₂ and tetragonal Eu₂SO₆ phases, with composition-tunable dielectric properties, is presented. Using a homodiffusive-controlled epitaxial growth method, materials are achieved with complementary characteristics: the hexagonal Eu₂SO₂ phase exhibits a high dielectric constant (≈30) paired with a moderate bandgap (≈4.56 eV), while the tetragonal Eu₂SO₆ phase offers a wider bandgap (≈5.62 eV) but a lower dielectric constant (≈20). The potential of these materials is demonstrated by integrating ultrathin Eu₂SO₂ nanoplates with molybdenum disulfide (MoS₂) field-effect transistors (FETs) via vdW forces. The resulting devices achieve a near-ideal I _on/I _off ratio (≈10⁸), minimal hysteresis (≈5.3 mV), a low subthreshold slope (≈63.5 mV dec⁻¹), and ultralow leakage current (≈10⁻¹⁴ A). These results highlight the capacity of europium oxysulfur compounds to address the trade-off between dielectric constant and bandgap, offering tailored solutions for diverse 2D electronic applications. This work underscores the potential of composition engineering to expand the family of rare-earth oxysulfur compounds for nanoelectronics, paving the way for innovative gate dielectrics in next-generation devices.

DNA nanotechnology based devices have emerged with new class of applications in tissue-specific targeted drug delivery, tissue engineering, immunomodulation, drug carriers, and biosensors along with precision tools for mechanobiology applications.

Abstract

DNA nanotechnology represents an innovative discipline that combines nanotechnology with biotechnology. It exploits the distinctive characteristics of deoxyribonucleic acid (DNA) to create nanoscale structures and devices with remarkable accuracy and functionality. Researchers may create complex nanostructures with precision and specialized functions using DNA's innate stability, adaptability, and capacity to self-assemble through complementary base-pairing interactions. Integrating multiple disciplines, known as nanobiotechnology, allows the production of sophisticated nanodevices with a broad range of applications. These include precise drug delivery systems, extremely sensitive biosensors, and the construction of intricate tissue scaffolds for regenerative medicine. Moreover, combining DNA nanotechnology with mechanobiology provides a new understanding of how small-scale mechanical stresses and molecular interactions affect cellular activity and tissue development. DNA nanotechnology has the potential to revolutionize molecular diagnostics, tissue engineering, and organ regeneration. This could lead to enormous improvements in biomedicine. This review emphasizes the most recent developments in DNA nanotechnology, explicitly highlighting its significant influence on mechanobiology and its growing involvement in organ engineering. It provides an extensive overview of present trends, obstacles, and future prospects in this fast-progressing area.

This work pioneers the in situ printing of high-entropy alloy (HEA) nanoparticles into the corresponding 3D nanoarchitectures with flexible elemental combinations and freeform geometries. The resulting nanostructures exhibit ultrahigh strength, excellent toughness, and superstability. By combining these properties, the 3D-printed HEA nanoarchitectures have the potential to revolutionize future nanodevices.

Abstract

System miniaturization is a key driver in developing nanoelectromechanical systems, sensors, and microchips. To enhance reliability and extend operational lifetimes, high-entropy alloys (HEAs) have emerged as promising materials due to their exceptional mechanical robustness and thermal stability. These advantageous properties are predominantly demonstrated in bulk HEA forms; however, research on small-dimensional HEAs is largely confined to nanoparticles, nanopillars, and thin films, limiting their broader applications in nanodevice systems. This study introduces nanoarchitectured HEAs that exhibit remarkable mechanical and thermal properties. Using a custom-designed 3D nanoprinter, HEA nanoparticles are printed in situ into complex nanoarchitectures, enabling flexible elemental combinations and freeform 3D geometries. Structural dimensions and grain size are precisely controlled as design parameters to synergistically leverage the benefits of alloying, size scaling, and architectural design. The resulting 3D-printed HEA nanoarchitectures demonstrate ultrahigh strength (≈4 GPa), outstanding toughness, and exceptional thermal stability. These properties position nano-architectured HEAs as a novel class of materials suitable for high-stress, high-toughness applications in small-dimensional devices. By combining the versatility of 3D nanoprinting with the expansive alloy design space of HEAs, this approach paves the way for their potential integration into future nanodevices.

This review provides an overview of the structures of 2D molecular crystals (2D MCs) and strategies to modify their morphology and properties. Next, it summarizes preparation methods for large-scale 2D MCs by solution-based processes or vapor deposition. Finally, it highlights the applications of 2D MCs in electronic and optoelectronic devices with the advantages of tunable properties and scalable preparation methods.

Abstract

2D molecular crystals (2D MCs) are an emerging family of 2D materials formed by organic or inorganic molecules held together entirely by weak intermolecular forces. 2D MCs are gaining attention in electronics and optoelectronics due to their structural diversity, scalability, and strong light–matter interactions. This review provides a comprehensive overview of 2D MCs and their potential in electronic and optoelectronic applications. It begins by highlighting the structural features and properties of key 2D MCs discovered to date, focusing on three strategies to manipulate intermolecular forces for better control over crystal morphology and properties. Then various methods are explored for fabricating large-area, highly-oriented 2D MCs, with an emphasis on vapor-phase and liquid-phase techniques. Last, their applications are reviewed in electronic and optoelectronic devices, such as channel materials, photosensitive components, and dielectrics. It is concluded by discussing future challenges and opportunities in the field, offering insights into scalable production and industrial applications of 2D MCs.

Nature Communications, Published online: 31 January 2025; doi:10.1038/s41467-025-56343-6

During cell adhesion, integrins are typically thought to require immobilized ligands for spreading. Here, the authors demonstrate that cells can spread and form mature integrin adhesions on fluid substrates by interacting with high-affinity Invasin ligands.

Studying the functional consequences of structural variants (SVs) in mammalian genomes is challenging because (i) SVs arise much less commonly than single-nucleotide variants or small indels and (ii) methods to generate, map, and characterize SVs in ...

The studies on multi-layered cuprates offer insights into the pairing mechanisms of superconductivity. However, the synthesis and stability of ultra-multilayered cuprates pose significant challenges. Here, a newly discovered seven-layered cuprate, CuBa₂Ca₆Cu₇O_{17± δ} , grown under high pressure is reported. Its bulk superconductivity, critical current density, and irreversibility fields are also investigated. The CuBa₂Ca₆Cu₇O_{17± δ} provides an ideal platform for delving into the physics of multi-layered cuprates.

Abstract

In cuprates, the superconducting transition temperature (T _c) is closely related to the number n of CuO₂ planes per unit cell. The studies on multi-layered cuprates offer insights into the physical properties and pairing mechanisms of superconductivity. However, the synthesis and stability of ultra-multilayered cuprates pose significant challenges. Here, a newly discovered seven-layered cuprate CuBa₂Ca₆Cu₇O_{17± δ} grown under high pressure is reported. Magnetization and transport measurements confirm bulk superconductivity with T _c of ≈85 K. The magnetization hysteresis loops, critical current density (J _c), and irreversibility fields of CuBa₂Ca₆Cu₇O_{17± δ} are also investigated. The novel compound CuBa₂Ca₆Cu₇O_{17± δ} provides an ideal platform for studying the physics of multi-layered cuprates.

A class of ultrathin GdOX with a high dielectric constant and breakdown field strength is synthesized via van der Waals epitaxy. The fabricated MoS₂ transistor gated by monocrystalline dielectric exhibits an on/off current ratio exceeding 10⁹ and a near-Boltzmann-limit SS, indicating their tangible applications in 2D electronics.

Abstract

Van der Waals (vdW) dielectrics are extensively employed to enhance the performance of 2D electronic devices. However, current vdW dielectric materials still encounter challenges such as low dielectric constant (κ) and difficulties in synthesizing high-quality single crystals. 2D rare-earth oxyhalides (REOXs) with exceptional electrical properties present an opportunity for the exploration of novel high-κ dielectrics. In this study, for the first time, the synthesis of a series of van der Waals layered gadolinium oxyhalides with thicknesses down to monolayer through a space-confined vdW epitaxy approach and demonstrating their application as a single-crystalline gate dielectric is reported. It exhibits a remarkable relative dielectric constant exceeding 17 and an impressive breakdown field strength of 13.5 MV cm⁻¹. The 2D transistors directly gated by the REOXs layer exhibit enhanced electron mobility and a low interface trap density. An ultrahigh on/off current ratio of 10⁹ and a near-Boltzmann-limit subthreshold swing is achieved. The superior dielectric properties, combined with the universality and scalability of the production method (e.g., millimeter-scale films are achieved), demonstrate that 2D REOXs can serve as promising gate dielectrics for 2D electronics, thereby expanding the study of high-κ vdW materials and potentially providing new opportunities for the development of low-power electronic devices.

Nature Communications, Published online: 26 January 2025; doi:10.1038/s41467-025-56206-0

Recently, a discrepancy arose in predicting the pairing symmetry of high-temperature superconductor La3Ni2O7. Xia et al. find that a slight increase in Ni-eg crystal field splitting sensitively alters the pairing symmetry of La3Ni2O7 from d-wave to s-wave.

The dynamic interaction between the nanochannels of mesoporous metal-organic frameworks (MOFs), the Ni-IRMOF-74 series, and i-motif DNA strands exhibiting pH-responsive conformational changes is investigated. The nanochannels can accommodate these DNA strand at neutral pH, while under acidic conditions, the tendency of the strand to form a four-stranded structure drives the release of the strand. Moreover, the proton-mediated dynamic interaction between the MOFs nanochannels and DNA strands can be coupled with the endocytosis processes, and the imaging of nucleus telomeres can be achieved due to the sequence complementarity between the i-motif DNA strand and telomere overhangs.

Abstract

With sequence-programmable biological functions and excellent biocompatibility, synthetic functional DNA holds great promise for various biological applications. However, it remains a challenge to simultaneously retain their biological functions while protecting these fragile oligonucleotides from the degradation by nucleases abundant in biological circumstances. Herein, a smart delivery system for functional DNA payloads is developed based on proton-mediated dynamic nestling of cytosine-rich DNA moieties within the precisely size-matched nanochannels of highly crystalline metal–organic frameworks (MOFs): At neutral pH, cytosine-rich DNA strands exhibit a flexible single-stranded state and can be accommodated by MOFs nanochannels with a size of ca. 2.0 nm; while at acidic conditions, the protonation of cytosine-rich strands weakens their interaction with the nanochannels, and the tendency to form four-stranded structures drives these DNA strands out of the nanochannels. Results confirm the successful protection of DNA payloads from enzymatic hydrolysis by the MOFs nanochannels, and the delicate coupling of the endocytosis processes and the proton-responsive Cytosine-rich DNA/MOFs systems realized the efficient intracellular delivery of DNA payloads. Furthermore, with a complementary sequence to the telomere overhangs, direct imaging of telomeres and the nucleus is successfully achieved with the proton-mediated DNA/MOFs system.

Nature Communications, Published online: 23 January 2025; doi:10.1038/s41467-025-56386-9

High dielectric constant (κ) materials compatible with van der Waals materials are desired to promote the development of 2D electronics. Here, the authors report a method to grow Mn3O4 nanosheets exhibiting κ up to 135 and equivalent oxide thickness down to 0.8 nm, enabling the fabrication of high-performance 2D MoS2 transistors.

ZnFe₂O₄ nanoparticles self-assemble in situ effectively and introduce mechanical force simulating primary biomechanical into the tiny target spot of TME through wireless magnetic control, which effectively inhibits tumor migration.

Abstract

Mechanical force attracts booming attention with the potential to tune the tumor cell behavior, especially in cell migration. However, the current approach for introducing mechanical input is difficult to apply in vivo. How the mechanical force affects cell behavior in situ also remains unclear. In this work, an intelligent miniaturized platform is constructed with magnetic ZnFe₂O₄ (ZFO) micromotors. The wireless ZFO can self-assemble in situ and rotate to generate mechanical torque of biologically relevant piconewton-scale at the target tumor site. It is observed unexpectedly that enhanced in situ mechanical rotating torque from ZFO micromotors and the active fluid inhibit the migration of highly invasive A549 tumor cells. The down-regulation of the Piezo1 channel and the suppressed signaling of ROCK1 in mechano-adaptive tumor cells is found to be related to the inhibition effect. With effectiveness confirmed with the zebrafish xenograft model, this platform provides a valuable toolkit for mechanobiology and force-associated non-invasive tumor therapy.

Green and red quantum dot (QD) luminescence microspheres with simultaneous excellent color conversion performance and high photoluminescence stability are synthesized by a facile wet chemical process. They further serve as color conversion materials for the fabrication of green and red micro-LEDs, which exhibit world-record external quantum efficiencies of 40.8% and 22.1% and high brightnesses of 1.7 × 10⁸ and 7.6 × 10⁷ cd m⁻².

Abstract

Quantum dot (QD)-converted micrometer-scale light-emitting diodes (micro-LEDs) are regarded as an effective solution for achieving high-performance full-color micro-LED displays because of their narrow-band emission, simplified mass transfer, facile drive circuits, and low cost. However, these micro-LEDs suffer from significant blue light leakage and unsatisfactory electroluminescence properties due to the poor light conversion efficiency and stability of the QDs. Herein, the construction of green and red QD luminescence microspheres with the simultaneously high conversion efficiency of blue light and strong photoluminescence stability are proposed. These luminescence microspheres exhibit high external photoluminescence quantum yields exceeding 46% under 450 nm excitation, along with excellent reliability against blue light, heat, and water-oxygen degradation, owing to the waveguide and spatial confinement effects of the microspheres. The microsphere-based green and red micro-LEDs achieve world-record external quantum efficiencies of 40.8% and 22.1%, respectively, and high brightness values of 1.7 × 10⁸ and 7.6 × 10⁷ cd m⁻², respectively. Finally, 0.6 inch red, green, and blue monochrome micro-LED displays are demonstrated by integrating microsphere-converted micro-LED arrays with thin-film transistor backplanes, which show a pixel resolution as high as 1700 PPI and brightness exceeding 10 000 cd m⁻².

Bi-directional or bipolar photoresponses are extensively developed for advanced intelligent sensing and detection in  (2D) materials, bridging the gap between neuromorphic models and sensing devices. Here, four novel types of bi-directional photoelectric responses and the diverse strategies for their implementation are comprehensively summarized. These four bi-directional responses enable four corresponding cutting-edge sensing applications.

Abstract

With the rapid advancement of 2D material-based optoelectronic devices, significant progress is made in the development of all-optical logic devices, synaptic biomimetic devices, and multidimensional detection systems. As entering to the high-speed information era, there is an urgent demand for complex, compact, multifunctional, low-energy, and high-speed intelligent sensing chips. Examining the evolution of current technologies reveals a parallel in the advancement of bipolar response mechanisms-from simple positive and negative responses to more intricate inhibition-promotion dynamics with persistent characteristics. This evolution significantly broadens their applications in biomimetic devices. Moreover, compared to unipolar responses, complex bipolar responses offer greater flexibility in adaptation and a unique one-to-one mapping with high-dimensional information parameters such as polarization, phase, and spectrum, positioning them as promising candidates for breakthroughs in multidimensional detection and resolution. In this review, design strategies are comprehensively explored for various bipolar responses in 2D materials, highlighting their deep applications and progress in advanced fields. It is aimed for this review to provide a broad overview of bi-directional response mechanisms, offering inspiration for designing the next generation of intelligent sensing chips.

Highlights

• Two-dimensional (2D) materials are highlighted for their exceptional mechanical, electrical, optical, and chemical properties, making them ideal for fabricating high-performance wearable biodevices.

• The review categorizes cutting-edge wearable biodevices by their interactions with physical, electrophysiological, and biochemical signals, showcasing how 2D materials enhance these devices' functionality, mainly including self-powering and human-machine interaction.

• 2D materials enable multifunctional, high-performance biodevices, integrating self-powered systems, treatment platforms, and human-machine interactions, though challenges remain in practical applications.

This study presents a fully wireless in vivo signal acquisition system featuring a biodegradable passive tag incorporating a tunable gelatin-ionic liquid substrate and a nanoscale crack-based strain gauge sensor, along with a wearable reader patch for interrogating with the implanted passive tag and transmitting sensor response to peripheral devices. The proposed system demonstrates real-time efficacy in recording and processing superimposed vital signs.

Abstract

State-of-the-art biosignal monitoring systems strive to achieve a balance between biocompatibility, biodegradability, and miniaturized, unobtrusive signal acquisition, thus requiring further research for improved user safety, mobility, and comfort. Here, a fully wireless sensing system is presented for real-time in vivo assessment of physiological vital signs, addressing these challenges to enhance performance and user experience. The system features a biodegradable passive tag with a nanoscale crack-based strain gauge sensor connected to a coil antenna on a gelatin-ionic liquid substrate (GIS). The thermal crosslinking in the GIS promotes adhesion, while the presence of ionic liquid decreases the self-resonance frequency of the BCA to below 100 MHz, enabling the device to operate in detuned mode. A lightweight (1.547 g) wearable reader patch interrogates an implanted passive tag via near-field inductive coupling and transmits sensory data to peripheral devices via Bluetooth. Thus, the system ensures minimal tissue absorption and extended transmission range while consuming ≈80 mW of power during operation. In vitro and in vivo studies, culminating in successful implementation within a rat model, validated the implanted tag's biocompatibility and the system's capability to wirelessly acquire and process superimposed physiological vital signs, highlighting its potential to enhance patient outcomes through improved diagnostic and monitoring practices.

Nature Materials, Published online: 17 January 2025; doi:10.1038/s41563-024-02060-2

Electric fields guide collective cell migration in developing embryos of Xenopus laevis via a voltage-sensitive phosphatase.

MXenes, particularly Ti₃C₂T×, are a promising class of 2D materials with exceptional properties like high electrical conductivity and tunable work functions. This review highlights their potential in enhancing silicon-based optoelectronic devices, including solar cells and photodetectors. Key focus areas include MXene composition, synthesis, properties, and their impact on device performance, along with current challenges and future opportunities for their integration into the silicon-dominated semiconductor industry.

Abstract

MXenes, a rapidly emerging class of 2D transition metal carbides, nitrides, and carbonitrides, have attracted significant attention for their outstanding properties, including high electrical conductivity, tunable work function, and solution processability. These characteristics have made MXenes highly versatile and widely adopted in the next generation of optoelectronic devices, such as perovskite and organic solar cells. However, their integration into silicon-based optoelectronic devices remains relatively underexplored, despite silicon's dominance in the semiconductor industry. In this review, a timely summary of the recent progress in utilizing Ti-based MXenes, particularly Ti₃C₂T_x, in silicon-based optoelectronic devices is provided. The composition, synthesis methods, and key properties of MXenes that contribute to their potential for enhanced device performance are focused on. Furthermore, the latest advancements in MXene applications in silicon-based solar cells and photodetectors are discussed from fundamental and applied perspectives. Finally, the key challenges and future opportunities for the integration of MXenes in silicon-based optoelectronic devices are outlined.

The moiré-scale friction behavior of a graphene-wrapped diamond tip sliding on a graphene/h-BN heterostructure is studied. The lattice mismatch between graphene and h-BN generates a hexagonal moiré pattern. Under high load, the lateral force steadily increases in domain regions before abruptly dropping at domain walls, a phenomenon known as moiré stick-slip. This behavior attenuates in multilayer systems.

Abstract

The ultralow friction properties of 2D materials present significant potential for energy-saving application. Atomic force microscopy experiments on the moiré superlattice of stacked 2D materials reveal that, beyond atomic stick-slip dynamics, friction behaviors at the moiré scale introduce a new dominant energy dissipation mechanism. However, understanding these behaviors remains challenging due to the complex interplay between atomic and moiré scale effects. Here, through large-scale molecular dynamics simulations of a tip scanning on a graphene/h-BN heterostructure, it is demonstrated that transitions between stick-slip and smooth sliding behaviors can be tuned at both atomic and moiré scales. Specifically, atomic-scale friction behavior is governed by the commensurability of tip-surface contact, while moiré-scale friction behavior arises from a load-dependent competition between expulsive interactions at tip/surface-indentation region and adhesive interactions at tip/surface-ripple region. The moiré stick-slip behavior occurs due to the more rapid shift of the protruding domain wall region as the tip crossing it under higher load. Furthermore, greater stretching of graphene bonds during domain wall crossing enhances energy dissipation. This moiré stick-slip behavior persists, albeit attenuated, in tri-layer systems. This findings provide new insights into friction at multiple length scales and may inform future studies of friction in multilayer superlattices.

Nature Communications, Published online: 16 January 2025; doi:10.1038/s41467-025-56055-x

Lattice mismatch in 2D van der Waals heterostructures induces lattice reconstruction to optimize the stacking. Here, the authors show how this introduces curving of different heterobilayers from deep-learning-assisted molecular dynamics simulations.

Centimeter-size, uniform 2D ErOCl film, and diverse 2D rare-earth materials are grown using self-encapsulation strategy. 2D ErOCl possesses high crystalline quality, excellent ambient and thermal stability. 2D ErOCl exhibits outstanding optical properties, featuring sub-meV narrow emissions at the telecom C-band. These emissions are tunable with external magnetic fields, highlighting their potential for advanced optical applications.

Abstract

Van der Waals (vdWs) materials are promising candidates for hetero-integration with silicon photonics toward miniaturization and integration. VdWs materials like molybdenum telluride and black phosphorus, despite being prominent, exhibit air sensitivity, and their room temperature emissions can be significantly broadened by tens of meV. Here, a self-encapsulation strategy is developed to scalably synthesize robust 2D vdWs ErOCl with sub-meV narrow emissions at the telecom C-band. Diverse 2D rare earth materials are also grown via chemical vapor deposition (TmOCl, YbOCl, HoOCl, DyOCl, SmOCl, NdOCl, TbOCl, GdOCl, EuOCl, and PrOCl), demonstrating the strategy's generalizability. The as-grown ErOCl exhibits high crystalline quality and excellent ambient and thermal stability (300 °C). Photoluminescence analysis reveals a series of narrow emissions across the visible to near-infrared spectrum. The ErOCl's emission at the telecom band is narrowest among 2D luminescent materials, and suitable for integrating with photonic chips. Temperature-dependent photoluminescence spectra facilitate the understanding of emission mechanisms, analyzed using a crystal field perturbation model. Moreover, these emissions can be tuned by external magnetic fields. This research not only pioneers a novel strategy for synthesizing 2D rare earth materials but also paves the way for innovative building blocks in the realm of on-chip optical communications.