Jiuxiang Dai

Soft Materials

In article number 2416095, Sebastien Rochat, Mark S. Workentin, Pierangelo Gobbo, and co-workers introduce two new hydrogels that respond to light and temperature, allowing creation of soft materials with controlled mechanical patterns. Applications include switchable actuators and mechanical data storage, with properties measured through microindentation. This advances soft materials science for robotics and information storage.

Nature Communications, Published online: 24 March 2025; doi:10.1038/s41467-025-58198-3

Bi2O2Se is a promising 2D semiconductor with high electron mobility and native high-k dielectric layers, but its p-type doping remains challenging. Here, the authors report a low-temperature substitutional doping method to fabricate 2D Bi2O2Se p-n junctions and p-type transistors

The review summarizes the principles, characteristics, and device structures of 2D vdW ferroelectric materials, as well as the applications and potential of these devices in neuromorphic computing, providing a comprehensive analysis of their advantages and the challenges that need to be addressed in the future.

Abstract

2D van der Waals (vdW) ferroelectric materials are emerging as transformative components in modern electronics and neuromorphic computing. The atomic-scale thickness, coupled with robust ferroelectric properties and seamless integration into vdW engineering, offers unprecedented opportunities for the development of high-performance and low-power devices. Notably, 2D ferroelectric devices excel in enabling multistate storage and neuromorphic functionalities in emulating synapses or retinas, positioning them as prime candidates for next-generation in-sensor-and-memory units. Despite ongoing challenges such as scalability, material stability, and uniformity, rapid interdisciplinary advancements and advancing nanofabrication processes are driving the field forward. This review delves into the fundamental principles of 2D ferroelectricity, highlights typical materials, and examines key device structures along with their applications in non-von Neumann architecture development and neuromorphic computing. By providing an in-depth overview, this work underscores the potential of 2D ferroelectric materials to revolutionize the future of electronics.

The MoS₂/Te van der Waals p-n junction memtransistors are fabricated to mimic synapses, which exhibit high rectification ratios up to 10⁵, a transition from short plasticity to long plasticity under illumination, and excellent nonvolatility with a retention time exceeding 6000 s. Based on this, a logical “OR” operation can be implemented. Meanwhile, artificial neural network training can be performed to achieve a high-recognition accuracy for handwritten digit recognition, demonstrating the potential of our artificial optoelectronic synapses in neuromorphic calculation.

Abstract

Memtransistors with nonvolatile storage, reconfigurability, and simulated synaptic functions are critical to overcoming the traditional von Neumann computer architecture bottleneck. Emerging two-dimensional van der Waals heterostructures (vdW) are promising candidates for constructing advanced three-terminal memtransistors by integrating the intriguing features of different materials and offering additional controllability over their existing optoelectronic properties. Herein, molybdenum disulfide (MoS₂)/Tellurene (Te) vdW p-n junction memtransistors are fabricated to mimic the plasticity, multi-bit memory, and paired-pulse facilitation behavior of biological synapses. The high surface potential difference and charge trapping of the MoS₂/Te heterostructure can endow the device with reconfigurable functionality through the transformation from short-term plasticity to long-term plasticity under illumination. Meanwhile, optoelectronic synaptic memtransistors also demonstrate nonvolatile behavior with a long retention time up to several hours, which can realize optical potentiation and electrical depression in one synaptic activity. On this basis, a logical operation of “OR” is realized by controlling the optical and electrical inputs. Moreover, artificial neural network training is performed to achieve a high recognition accuracy of 87.8% for handwritten digit recognition, demonstrating the potential of the artificial optoelectronic synapses in neuromorphic calculation.

This study explores 2D ferroelectric CuCrP₂S₆ for developing advanced NC-FET technology. Using MoS₂ as the channel material, NC-FETs with optimized capacitance matching conditions achieve ultra-steep subthreshold swings (12 mV dec⁻¹) and negligible hysteresis. A resistor-loaded inverter operating at 0.2 V with hysteresis-free characteristics highlights the potential of engineered 2D ferroelectrics for next-generation low-power electronics.

Abstract

The relentless pursuit of miniaturization and reduced power consumption in information technology demands innovative device architectures. Negative capacitance field-effect transistors (NC-FETs) offer a promising solution by harnessing the negative capacitance effect of ferroelectric materials to amplify gate voltage and achieve steep subthreshold swings (SS). In this work, 2D van der Waals (vdW) ferroelectric CuCrP₂S₆ (CCPS) is employed as the gate dielectric to realize hysteresis-free NC-FETs technology. Scanning microwave impedance microscopy (sMIM) is employed to investigate the dielectric property of CCPS, revealing a thickness-independent dielectric constant of ≈35. Subsequently, NC-FETs are fabricated with MoS₂ channel, and the capacitance matching conditions are meticulously investigated. The optimized devices exhibit simultaneously ultra-steep SS (≈12 mV dec⁻¹) and negligible hysteresis, with immunity to both voltage scan range and scan rate. Finally, a resistor-loaded inverter is demonstrated manifesting a low operation voltage down to 0.2 V and hysteresis-free transfer characteristics. This work paves the way for the development of high-performance, low-power electronics by exploiting 2D vdW ferroelectric materials.

Nature Materials, Published online: 24 March 2025; doi:10.1038/s41563-025-02170-5

The authors review the mechanisms of resistive switching in monolayer and bulk forms of two-dimensional layered materials, providing insights into atomic motions and electronic transport across interfaces.

Nature Communications, Published online: 21 March 2025; doi:10.1038/s41467-025-57986-1

Here, the authors develop an alkali-assisted chemical vapor deposition method to enhance the seeding process for WSe₂, and demonstrate the growth of 2-inch and centimeter-scale monolayer and bilayer WSe₂ films.

Rapid industrialization advancements have grabbed worldwide attention to integrate a very large number of electronic components into a smaller space for performing multifunctional operations. To fulfill the growing computing demand state-of-the-art materials are required for substituting traditional silicon and metal oxide semiconductors frameworks. Two-dimensional (2D) materials have shown their tremendous potential surpassing the limitations of conventional materials for developing smart devices. Despite their ground-breaking progress over the last two decades, systematic studies providing in-depth insights into the exciting physics of 2D materials are still lacking. Therefore, in this review, we discuss the importance of 2D materials in bridging the gap between conventional and advanced technologies due to their distinct statistical and quantum physics. Moreover, the inherent properties of these materials could easily be tailored to meet the specific requirements of smart devices. Hence, we discuss the physics of various 2D materials enabling them to fabricate smart devices. We also shed light on promising opportunities in developing smart devices and identified the formidable challenges that need to be addressed.

Nature Electronics, Published online: 20 March 2025; doi:10.1038/s41928-025-01353-x

Thin films of a single-crystal dielectric—antimony oxide—can be epitaxially grown at wafer scales on graphene-covered copper surfaces and then used to transfer dielectric/graphene stacks, or be integrated as a two-dimensional dielectric onto other materials.

Nature Physics, Published online: 20 March 2025; doi:10.1038/s41567-025-02828-6

Rotating material layers with respect to each other can change their electronic properties. Now, superconducting quasiparticles with a twisted configuration are demonstrated in a NbSe2 monolayer on graphene by controlling the twist angle.

Nature Physics, Published online: 20 March 2025; doi:10.1038/s41567-025-02803-1

It may be possible to find non-Abelian electronic states in the higher bands of flat-band materials. Now a detailed transport study of the second moiré band of twisted bilayer MoTe2 maps out several topological and magnetic states.

This study conclusively resolves the atomic configuration at the growth interface, unveiling a periodic molecular MoO₃ layer van der Waals epitaxially grown on a single Al-terminated sapphire (α-Al ₂ O₃) surface. This structure, distinct from prior reports, aligns perfectly with experimental data and enhances the interaction between molybdenum disulfide (MoS₂) and α-Al₂O₃. By introducing unique 1-fold symmetry, it enables unidirectional MoS₂ alignment, offering fresh insights into interfacial atomic engineering.

Abstract

The epitaxial growth of molybdenum disulfide (MoS₂) on sapphire substrates enables the formation of single-crystalline monolayer MoS₂ with exceptional material properties on a wafer scale. Despite this achievement, the underlying growth mechanisms remain a subject of debate. The epitaxial interface is critical for understanding these mechanisms, yet its exact atomic configuration has previously been unclear. In this study, a monolayer single-crystalline MoS₂ grown on a sapphire substrate is analyzed, decisively visualizing the atomic structure of the epitaxial interface and elucidating its role in epitaxial growth from an atomic perspective. The findings reveal that the interface consists of a periodic molecular MoO₃ interlayer, van der Waals epitaxially grown on a single Al-terminated sapphire surface. Additionally, it is discovered that MoO₃ coverage enhances surface interactions and introduces a unique atomic arrangement with 1-fold symmetry at the sapphire surface, thereby facilitating the unidirectional alignment of MoS₂. This discovery provides valuable insights into the growth mechanisms leading to single-crystalline MoS₂ formation, and suggests pathways for quantitatively monitoring and controlling growth dynamics, for the improvement of material quality and process repeatability, applicable for single-crystalline MoS₂ or potentially other transition metal dichalcogenides epitaxially grown on sapphire.

Nature, Published online: 19 March 2025; doi:10.1038/s41586-025-08686-9

All-electrical excitation of the hyperbolic phonon polaritons in hexagonal boron nitride by drifting charge carriers in nearby graphene results in electroluminescence at mid-infrared frequencies.

Nature Materials, Published online: 19 March 2025; doi:10.1038/s41563-025-02156-3

The authors present transport measurements of rhombohedral trilayer graphene proximitized by transition metal dichalcogenides. They find that the presence of transition metal dichalcogenides enables the emergence of new superconducting and metallic phases and affects the superconducting states present in bare rhombohedral trilayer graphene.

Nature Materials, Published online: 19 March 2025; doi:10.1038/s41563-025-02173-2

Metal–organic chemical vapour deposition enables the wafer-scale growth of hexagonal boron nitride with an AA stacking sequence that was previously considered thermodynamically unfavourable.

Nature Communications, Published online: 19 March 2025; doi:10.1038/s41467-025-57759-w

The fabrication of artificial crystals by reassembling monolayer semiconductors enables on-demand engineering of their excitonic properties. Here, the authors report an efficient stacking method to fabricate millimetre-scale van der Waals homo-/hetero-crystals, demonstrating enhanced monolayer-like photoluminescence emission and quadrupolar interlayer exciton emission.

npj 2D Materials and Applications, Published online: 17 March 2025; doi:10.1038/s41699-025-00542-8

Raman polarization switching in CrSBr

2D semiconductors are promising for sub-1 nm nodes, yet dielectric integration challenges hinder their applications. This review focuses the possible solutions include surface pretreatment, native oxides, buffer layers, vdW transfer, and new dielectric materials. The advanced 3D dielectric integration of 2D materials and the outlook are also discussed.

Abstract

As silicon-based transistors approach their physical limits, the challenge of further increasing chip integration intensifies. 2D semiconductors, with their atomically thin thickness, ultraflat surfaces, and van der Waals (vdW) integration capability, are seen as a key candidate for sub-1 nm nodes in the post-Moore era. However, the low dielectric integration quality, including discontinuity and substantial leakage currents due to the lack of nucleation sites during deposition, interfacial states causing serious charge scattering, uncontrolled threshold shifts, and bad uniformity from dielectric doping and damage, have become critical barriers to their real applications. This review focuses on this challenge and the possible solutions. The functions of dielectric materials in transistors and their criteria for 2D devices are first elucidated. The methods for high-quality dielectric integration with 2D channels, such as surface pretreatment, using 2D materials with native oxides, buffer layer insertion, vdW dielectric transfer, and new dielectric materials, are then reviewed. Additionally, the dielectric integration for advanced 3D integration of 2D materials is also discussed. Finally, this paper is concluded with a comparative summary and outlook, highlighting the importance of interfacial state control, dielectric integration for 2D p-type channels, and compatibility with silicon processes.

A new scanning probe technique, Scanning Electrocaloric Thermometry, enables the study of electrocaloric effects with nanoscale resolution by directly measuring local temperature changes under electric fields. Applied to In₂Se₃ and poly(vinylidene fluoride-trifluoroethylene), it reveals spatially varying electrocaloric and heat dissipation phenomena, opening new possibilities for nanoscale thermal characterization in energy-efficient cooling technologies.

Abstract

The electrocaloric effect refers to the temperature change in a material when an electric field is applied or removed. Significant breakthroughs revealed its potential for solid-state cooling technologies in past decades. These devices offer a sustainable alternative to traditional vapor compression refrigeration, with advantages such as compactness, silent operation, and the absence of moving parts or refrigerants. Electrocaloric effects are typically studied using indirect methods based on polarization data, which suffer from inaccuracies related to assumptions about heat capacity. Direct methods, although more precise, require device fabrication and face challenges in studying meso- or nanoscale systems, like 2D materials, and materials with non-uniform polarization textures where high spatial resolution is required. In this study, a novel technique, Scanning Electrocaloric Thermometry, is introduced for characterizing the local electrocaloric effect in nanomaterials. This approach achieves high spatial resolution by locally applying electric fields and by simultaneously measuring the resulting temperature change. By employing AC excitation, the measurement sensitivity is further enhanced and the electrocaloric effect is disentangled from other heating mechanisms such as Joule heating and dielectric losses. The effectiveness of the method is demonstrated by examining electrocaloric and heat dissipation phenomena in 2D In₂Se₃ micrometer-sized flakes poly(vinylidene fluoride-trifluoroethylene) films.

This is a quasi-dry transfer technique assisted by water vapor intercalation (WVI), which can be effectively used to fabricate high-quality twisted heterostructures, including monolayer/few-layer graphene and 2D quasicrystal-like heterostructure. It also enables the fabrication of suspended 2DMs and high-performance devices. This technique features excellent scalability, advancing fundamental research on 2DMs, and the fabrication of quantum devices with outstanding performance.

Abstract

Transfer technique has become an indispensable process in the development of two-dimensional materials (2DMs) and their heterostructures, as it determines the quality of the interface and the performance of the resulting devices. However, how to flexibly and conveniently fabricate two-dimensional (2D) twisted heterostructures with high-quality interfaces has always been a formidable challenge. Here, a quasi-dry transfer technique assisted by water vapor intercalation (WVI) is developed, which can be flexibly used to fabricate twisted heterostructures. This method leverages a charged hydrophilic surface to facilitate WVI at the interface, enabling the clean and uniform detachment of 2DMs from the substrate. Using this method, the twisted monolayer/few-layer graphene and 2D quasicrystal-like WS₂/MoS₂, highlighting the surface/interface cleanness and angle-controlled transfer method is successfully fabricated. Besides, suspended structures of these 2DMs and heterostructures are fabricated, which offers substantial convenience for studying their intrinsic physical properties. Further, a high-performance hBN/graphene/hBN superlattice device with the mobility of ≈199,000 cm² V⁻¹ s⁻¹ at room temperature is fabricated. This transfer technique ingeniously combines the advantages of dry transfer and wet transfer. Moreover, it features excellent scalability, providing crucial technical support for future research on the fundamental physical properties of 2DMs and the fabrication of quantum devices with outstanding performance.

Emerging two-dimensional (2D) semiconductors are among the most promising materials for ultra-scaled transistors due to their intrinsic atomic-level thickness. As the stacking process advances, the complexity and cost of nanosheet field-effect transistors (NSFETs) and complementary FET (CFET) continue to rise. The 1 nm technology node is going to be based on Si-CFET process according to international roadmap for devices and systems (IRDS) (2022, https://irds.ieee.org/), but not publicly confirmed, indicating that more possibilities still exist. The miniaturization advantage of 2D semiconductors motivates us to explore their potential for reducing process costs while matching the performance of next-generation nodes in terms of area, power consumption and speed. In this study, a comprehensive framework is built. A set of MoS2 NSFETs were designed and fabricated to extract the key parameters and performances. And then for benchmarking, the sizes of 2D-NSFET are scaled to a extent that both of the Si-CFET and 2D-NSFET have the same average device footprint. Under these conditions, the frequency of ultra-scaled 2D-NSFET is found to improve by 36% at a fixed power consumption. This work verifies the feasibility of replacing silicon-based CFETs of 1 nm node with 2D-NSFETs and proposes a 2D technology solution for 1 nm nodes, i.e., “2D eq 1 nm” nodes. At the same time, thanks to the lower characteristic length of 2D semiconductors, the miniaturized 2D-NSFET achieves a 28% frequency increase at a fixed power consumption. Further, developing a standard cell library, these devices obtain a similar trend in 16-bit RISC-V CPUs. This work quantifies and highlights the advantages of 2D semiconductors in advanced nodes, offering new possibilities for the application of 2D semiconductors in high-speed and low-power integrated circuits.

Publication date: June 2025

Source: Materials Today, Volume 85

Author(s): Kaiwen Li, Lidan Wang, Feifan Chen, Jiahao Lu, Rui Guo, Yue Gao, Shiyu Luo, Xin Ming, Yue Lin, Zhen Xu, Manyi Huang, Chao Wang, Yingjun Liu, Chao Gao

Publication date: July 2025

Source: Materials Today, Volume 86

Author(s): Jikai Zhang, Yi Tao, Yuxuan Ye, Haiyang Wang, Xinping Wu, Zicheng Luo, Yu Shi, Qi Zhao, Zongju Cheng, Yu Guo, Bin Li, Bo Mai, Qinyou An, Xiansheng Zhang, Zhiguo Du, Shubin Yang

Nature Physics, Published online: 18 March 2025; doi:10.1038/s41567-025-02822-y

Metallic altermagnets are promising for applications due to the spin-polarized electric current that originates from their spin-split band structure. Now d-wave altermagnetism with antisymmetric spin polarization has been demonstrated in KV2Se2O.

Author(s): Yichen Liu, San-Dong Guo, Yongpan Li, and Cheng-Cheng Liu

Antiferromagnetic spintronics has long been a subject of intense research interest, and the recent introduction of altermagnetism has further ignited enthusiasm in the field. However, fully compensated ferrimagnetism, which exhibits band spin splitting but zero net magnetization, has yet to receive …

[Phys. Rev. Lett. 134, 116703] Published Tue Mar 18, 2025

Author(s): Kostiantyn V. Yershov, Olena Gomonay, Jairo Sinova, Jeroen van den Brink, and Volodymyr P. Kravchuk

The altermagnetic nature of a large class of magnetically ordered materials is the source of a wide range of new effects. Here, we show that the merging of two areas, namely the altermagnetism and the physics of curvilinear low-dimensional magnets gives rise to a distinct novel physical effect: a cu…

[Phys. Rev. Lett. 134, 116701] Published Mon Mar 17, 2025