Publications by authors named "Xidong Duan"

Memristors and magnetic tunnel junctions are showing great potential in data storage and computing applications. A magnetoelectrically coupled memristor utilizing electron spin and electric field-induced ion migration can facilitate their operation, uncover new phenomena, and expand applications. In this study, devices consisting of Pt/(LaCoO/SrTiO)/LaCoO/Nb:SrTiO (Pt/(LCO/STO)/LCO/NSTO) are engineered using pulsed laser deposition to form the LCO/STO superlattice layer, with Pt and NSTO serving as the top and bottom electrodes, respectively.

View Article and Find Full Text PDF

Hot spots can generate intense local electromagnetic (EM) fields, thereby boosting diverse innovative applications. However, these applications may face challenges due to their subtle structural changes that can significantly impact their EM field strength. Herein, we report a large-scale synthesis of monodisperse, highly spherical, single crystalline (SC) Au nanospheres (Au NSs) with tunable sizes ranging from 38 to 92 nm for constructing uniform and reproducible hot spots with a nanosphere-on-mirror (NSoM) configuration.

View Article and Find Full Text PDF
Article Synopsis
  • Two-dimensional transition metal dichalcogenides (TMDs) have attracted significant interest due to their impressive physical and chemical properties, making them useful in (opto)electronics, electrocatalysis, and energy storage.
  • The traditional chemical vapor deposition (CVD) method for synthesizing TMDs faces challenges such as high precursor melting points and difficulty in creating a uniform precursor atmosphere.
  • The spin-coating precursor mediated chemical vapor deposition (SCVD) method improves upon traditional CVD by allowing for a cleaner, more uniform growth and offering better control over material thickness and purity through the manipulation of solution parameters.
View Article and Find Full Text PDF
Article Synopsis
  • - The study focuses on using atomic substitution to create precise semiconductor heterostructures in two-dimensional (2D) materials, which is essential for advancing technology.
  • - Researchers successfully synthesized monolayer WSe-WS heterostructures with a sharp interface by applying a high-temperature chalcogen atom-exchange method, controlling the reaction through time and temperature.
  • - The methods employed included spectroscopies and microscopy to analyze the process, revealing that strain plays a significant role in transforming the materials, showcasing a new way to engineer 2D materials at the atomic level.
View Article and Find Full Text PDF

Two dimension (2D) transition metal dichalcogenides (TMD) heterostructures have opened unparalleled prospects for next-generation electronic and optoelectronic applications due to their atomic-scale thickness and distinct physical properties. The chemical vapor deposition (CVD) method is the most feasible approach to prepare 2D TMD heterostructures. However, the synthesis of 2D vertical heterostructures faces competition between in-plane and out-of-plane growth, which makes it difficult to precisely control the growth of vertical heterostructures.

View Article and Find Full Text PDF

Two-dimensional transition metal dichalcogenides, which feature atomically thin geometry and dangling-bond-free surfaces, have attracted intense interest for diverse technology applications, including ultra-miniaturized transistors towards the subnanometre scale. A straightforward exfoliation-and-restacking approach has been widely used for nearly arbitrary assembly of diverse two-dimensional (2D) heterostructures, superlattices and moiré superlattices, providing a versatile materials platform for fundamental investigations of exotic physical phenomena and proof-of-concept device demonstrations. While this approach has contributed importantly to the recent flourishing of 2D materials research, it is clearly unsuitable for practical technologies.

View Article and Find Full Text PDF

Two-dimensional (2D) transition metal dichalcogenide (TMD) heterostructures have attracted a lot of attention due to their rich material diversity and stack geometry, precise controllability of structure and properties, and potential practical applications. These heterostructures not only overcome the inherent limitations of individual materials but also enable the realization of new properties through appropriate combinations, establishing a platform to explore new physical and chemical properties at micro-nano-pico scales. In this review, we systematically summarize the latest research progress in the synthesis, modulation, and application of 2D TMD heterostructures.

View Article and Find Full Text PDF

Vertical transistors, in which the source and drain are aligned vertically and the current flow is normal to the wafer surface, have attracted considerable attention recently. However, the realization of high-density vertical transistors is challenging, and could be largely attributed to the incompatibility between vertical structures and conventional lateral fabrication processes. Here we report a T-shape lamination approach for realizing high-density vertical sidewall transistors, where lateral transistors could be pre-fabricated on planar substrates first and then laminated onto vertical substrates using T-shape stamps, hence overcoming the incompatibility between planar processes and vertical structures.

View Article and Find Full Text PDF

The tunable properties of halide perovskite/two dimensional (2D) semiconductor mixed-dimensional van der Waals heterostructures offer high flexibility for innovating optoelectronic and photonic devices. However, the general and robust growth of high-quality monocrystalline halide perovskite/2D semiconductor heterostructures with attractive optical properties has remained challenging. Here, we demonstrate a universal van der Waals heteroepitaxy strategy to synthesize a library of facet-specific single-crystalline halide perovskite/2D semiconductor (multi)heterostructures.

View Article and Find Full Text PDF

Precise synthesis of all-inorganic lead halide perovskite nanowire heterostructures and superlattices with designable modulation of chemical compositions is essential for tailoring their optoelectronic properties. Nevertheless, controllable synthesis of perovskite nanostructure heterostructures remains challenging and underexplored to date. Here, we report a rational strategy for wafer-scale synthesis of one-dimensional periodic CsPbCl/CsPbI superlattices.

View Article and Find Full Text PDF

Two-dimensional (2D) FeSn, which is a room-temperature ferromagnetic kagome metal, has potential applications in spintronic devices. However, the systematic synthesis and magnetic study of 2D FeSn single crystals have rarely been reported. Here we have synthesized 2D hexagonal and triangular FeSn nanosheets by controlling the amount of FeCl precursors in the chemical vapor deposition (CVD) method.

View Article and Find Full Text PDF

Interfacial self-assembly is a well-established method for the preparation of a two-dimensional (2D) metal nanofilm from nanoscale building blocks. However, the as-prepared nanofilm exhibits limited conductivity because of the large contact resistance at the junctions among its building blocks. Here, we report a salt-assisted, in situ current nanowelding strategy to weld an interfacial Au nanoparticle (NP) film for downstream applications, such as high-performance electrocatalysts.

View Article and Find Full Text PDF
Article Synopsis
  • Two-dimensional (2D) semiconductors are gaining attention for their potential in three-dimensional (M3D) circuit integration due to their unique properties, but they face challenges with traditional high-energy processing methods.
  • A new low-temperature method was developed, using van der Waals (vdW) lamination to stack prefabricated 2D circuit tiers at only 120°C, allowing for the creation of 10 circuit tiers vertically without damaging underlying components.
  • This innovative approach enables vertical connections between different tiers, leading to the development of complex logic and heterogeneous structures, thus expanding the potential for advanced M3D circuit designs.
View Article and Find Full Text PDF

Objectives: To compare the clinical effect of combined therapy of acupotomy and electroacupuncture (EA) with the simple application of EA on knee osteoarthritis (KOA), and their influence on knee function.

Methods: Sixty-eight KOA patients were randomly divided into 2 groups, an acupotomy group and an EA group. In the acupotomy group, the combined therapy of acupotomy and EA was adopted.

View Article and Find Full Text PDF

The characterization of inverted structures (crystallographic, ferroelectric, or magnetic domains) is crucial in the development and application of novel multi-state devices. However, determining these inverted structures needs a sensitive probe capable of revealing their phase correlation. Here a contrast-enhanced phase-resolved second harmonic generation (SHG) microscopy is presented, which utilizes a phase-tunable Soleil-Babinet compensator and the interference between the SHG fields from the inverted structures and a homogeneous reference.

View Article and Find Full Text PDF
Article Synopsis
  • The study discusses the creation of ultrathin CoSi nanoplates, which can be adjusted to a thickness of 2.2 nm, enhancing their magnetic properties.
  • The unique shape and interfacial magnetism contribute to strong perpendicular magnetic anisotropy and hard ferromagnetism at room temperature, with a high Curie temperature of over 950 K.
  • The intrinsic oxide layer protects these nanoplates, ensuring they remain stable in various environments, making them promising candidates for future Si-based spintronic applications.
View Article and Find Full Text PDF

Emerging 2D chromium-based dichalcogenides (CrX (X = S, Se, Te; 0 < ≤ 2)) have provoked enormous interests due to their abundant structures, intriguing electronic and magnetic properties, excellent environmental stability, and great application potentials in next generation electronics and spintronics devices. Achieving stoichiometry-controlled synthesis of 2D CrX is of paramount significance for such envisioned investigations. Herein, we report the stoichiometry-controlled syntheses of 2D chromium selenide (CrSe) materials (rhombohedral CrSe and monoclinic CrSe) via a Cr-self-intercalation route by designing two typical chemical vapor deposition (CVD) strategies.

View Article and Find Full Text PDF

2D compounds (A = Al, Ga, In, and B = S, Se, and Te) with intrinsic structural defects offer significant opportunities for high-performance and functional devices. However, obtaining 2D atomic-thin nanoplates with non-layered structure on SiO/Si substrate at low temperatures is rare, which hinders the study of their properties and applications at atomic-thin thickness limits. In this study, the synthesis of ultrathin, non-layered α-InTe nanoplates is demonstrated using a BiOCl-assisted chemical vapor deposition method at a temperature below 350 °C on SiO/Si substrate.

View Article and Find Full Text PDF

van der Waals heterostructures (vdWHs) based on two-dimensional (2D) semiconductors have attracted considerable attention. However, the reported vdWHs are largely based on vertical device structure with large overlapping area, while the realization of lateral heterostructures contacted through 2D edges remains challenging and is majorly limited by the difficulties of manipulating the lateral distance of 2D materials at nanometer scale (during transfer process). Here, we demonstrate a simple interfacial sliding approach for realizing an edge-by-edge lateral contact.

View Article and Find Full Text PDF

WSe has a high mobility of electrons and holes, which is an ideal choice as active channels of electronics in extensive fields. However, carrier-type tunability of WSe still has enormous challenges, which are essential to overcome for practical applications. In this work, the direct growth of n-doped few-layer WSe is realized via defect engineering.

View Article and Find Full Text PDF

For exploring advanced Zn-ion batteries (ZIBs) with long lifespan and high Coulombic efficiency (CE), the critically important point is to limit the undesired Zn dendrite and parasitic reactions. Among the coating for electrode is a promising strategy, relying on the trade-off between its thickness and stability to achieve the ultra-stable Zn anodes in ZIBs. Herein, a submicron-thick (≈0.

View Article and Find Full Text PDF

Strain engineering has been proposed as a promising method to boost the carrier mobility of two-dimensional (2D) semiconductors. However, state-of-the-art straining approaches are largely based on putting 2D semiconductors on flexible substrates or rough substrate with nanostructures (., nanoparticles, nanorods, ripples), where the observed mobility change is not only dependent on channel strain but could be impacted by the change of dielectric environment as well as rough interface scattering.

View Article and Find Full Text PDF

The practical application of two-dimensional (2D) semiconductors for high-performance electronics requires the integration with large-scale and high-quality dielectrics-which however have been challenging to deposit to date, owing to their dangling-bonds-free surface. Here, we report a dry dielectric integration strategy that enables the transfer of wafer-scale and high-κ dielectrics on top of 2D semiconductors. By utilizing an ultra-thin buffer layer, sub-3 nm thin AlO or HfO dielectrics could be pre-deposited and then mechanically dry-transferred on top of MoS monolayers.

View Article and Find Full Text PDF

Two-dimensional (2D) semiconductors such as molybdenum disulfide (MoS) have attracted tremendous interest for transistor applications. However, the fabrication of 2D transistors using traditional lithography or deposition processes often causes undesired damage and contamination to the atomically thin lattices, partially degrading the device performance and leading to large variation between devices. Here we demonstrate a highly reproducible van der Waals integration process for wafer-scale fabrication of high-performance transistors and logic circuits from monolayer MoS grown by chemical vapour deposition.

View Article and Find Full Text PDF