Xidong Duan

Hunan University · State Key Laboratory of Chemo/Biosensing and Chemometrics

Over the past 70 years, the semiconductor industry has undergone transformative changes, largely driven by the miniaturization of devices and the integration of innovative structures and materials. Two-dimensional (2D) materials like transition metal dichalcogenides (TMDs) and graphene are pivotal in overcoming the limitations of silicon-based tech...

Two-dimensional (2D) semiconductors have shown great potential for monolithic three-dimensional (M3D) integration due to their dangling-bonds-free surface and the ability to integrate to various substrates without the conventional constraint of lattice matching1–10. However, with atomically thin body thickness, 2D semiconductors are not compatible...

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 2 /Si substrate at low temperatures is rare, which hinders the study of their properties and applications a...

Two-dimensional (2D) metallic transition metal dichalcogenides (TMDs) have garnered significant attention as promising candidates for various applications, including electronics, spintronics, and energy-related fields. Their appeal lies in their exceptional electronic conductivity, room-temperature ferromagnetism, charge density wave (CDW) phenomen...

Heterostructures made using two-dimensional semiconducting transition metal dichalcogenides could be used to build next-generation electronic devices. However, their performance is limited by low-quality metal–semiconductor contacts, and it remains challenging to create contacts with variable work functions using metals or metallic transition metal...

Moiré-trapped interlayer excitons within two-dimensional (2D) moiré superlattices offer a remarkably versatile and adaptable platform, enabling an extensive exploration of dipole interactions and many-body correlations in the realm of 2D quantum systems. Conversely, optical microcavities, capable of confining photons within a confined space, profou...

The controllable synthesis of complicated nanostructures in advanced two‐dimensional (2D) semiconductors, such as periodic regular hole arrays, is essential and remains immature. Here, we report a green, facile, highly controlled synthetic method to efficiently pattern 2D semiconductors, such as periodic regular hexagonal‐shaped hole arrays (HHA),...

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 (e.g., nanoparticles, nanorods, ripples), where the observed mobi...

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 o...

Moiré superlattices are formed by stacking 2D materials with a twist angle and have recently gained attention as a platform for investigating the interactions and correlations of moiré-trapped interlayer excitons (IXs). However, understanding these excitons remains challenging, as theoretical predictions suggest the existence of both parallel and a...

Two-dimensional (2D) semiconductors such as molybdenum disulfide (MoS2) 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 perfo...

The controlled etching of two‐dimensional transition metal dichalcogenides (2D‐TMDs) is critical to understanding the growth mechanisms of 2D materials and patterning 2D materials but remains a major comprehensive challenge. Here, we report a rational strategy to control the terminal atoms of 2D‐TMDs etched holes. Using laser irradiation combined w...

Antiferromagnets with non‐collinear spin order are expected to exhibit unconventional electromagnetic response, such as spin Hall effects, chiral abnormal, quantum Hall effect and topological Hall effect. In this work, we synthesized two‐dimensional (2D) thickness‐controlled and high‐quality Cr5Si3 nanosheets that is compatible with the CMOS techno...

Moiré superlattices in twisted van der Waals materials offer a powerful platform for exploring light‐matter interactions. The periodic moiré potentials in moiré superlattices can induce strongly correlated quantum phenomena such as moiré excitons, superconductivity and the Mott‐insulating state, all of which depend on the moiré potential associated...

Two-dimensional (2D) materials with large linear magnetoresistance (LMR) are very interesting owing to their potential application in magnetic storage or sensor devices. Here, we report the synthesis of 2D MoO2 nanoplates grown by a chemical vapor deposition (CVD) method and observe large LMR and nonlinear Hall behavior in MoO2 nanoplates. As-obtai...

Van der Waals (vdW) metallic contacts have been demonstrated as a promising approach to reduce the contact resistance and minimize the Fermi level pinning at the interface of two-dimensional (2D) semiconductors. However, only a limited number of metals can be mechanically peeled and laminated to fabricate vdW contacts, and the required manual trans...

Two‐dimensional metal oxides (2DMOs) have stimulated tremendous attention due to their distinct electronic structures and abundant surface chemistry. However, it remains a standing challenge for the synthesis of 2DMOs because of their intrinsic 3D lattice structure and ultrahigh synthesis temperature. Here, a reliable WSe2‐assisted chemical vapor d...

2D materials with mixed crystal phase will lead to the nonuniformity of performance and go against the practical application. Therefore, it is of great significance to develop a valid method to synthesize 2D materials with typical stoichiometry. Here, 2D palladium sulfides with centimeter scale and uniform stoichiometric ratio are synthesized via c...

The detection of ultraviolet (UV) radiation with effective performance and robust stability is essential to practical applications. Metal halide single‐crystal perovskites (ABX3) are promising next‐generation materials for UV detection. The device performance of all‐inorganic CsPbCl3 photodetectors (PDs) is still limited by inner imperfection of cr...

Most of the current methods for the synthesis of two-dimensional materials (2DMs) require temperatures not compatible with traditional back-end-of-line (BEOL) processes in semiconductor industry (450 °C). Here, we report a general BiOCl-assisted chemical vapor deposition (CVD) approach for the low-temperature synthesis of 27 ultrathin 2DMs. In part...

Synthesis of high-quality metal nanoparticles (NPs) is the premise toward their downstream diverse applications. Although some electrochemical synthesis strategies have been developed, the necessary use of high-concentration electrolyte solution as current pathway and reaction medium severely limits the colloidal stability of the growing NPs in the...

Single crystal metal halide perovskites thin films are considered to be a promising optical, optoelectronic materials with extraordinary performance due to their low defect densities. However, it is still difficult to achieve large‐scale perovskite single‐crystal thin films (SCTFs) with tunable bandgap by vapor‐phase deposition method. Herein, the...

Two-dimensional (2D) materials have demonstrated promising potential for flexible electronics, owning to their atomic thin body thickness and dangling-bond-free surface. Here, we report a sliding contact device structure for efficient strain releasing. By fabricating a weakly coupled metal-2D junction with a van der Waals (vdW) gap in between, the...

Two-dimensional semiconductors such as layered transition metal dichalcogenides can offer superior immunity to short-channel effects compared with bulk semiconductors such as silicon. As a result, these materials can be used to create highly scaled transistors. However, on-state current densities of two-dimensional semiconductor transistors are sti...

The increase of gate leakage current when the gate dielectric layer is thinned is a key issue for device scalability. For scaling down the integrated circuits, a thin gate dielectric layer with a low leakage current is essential. Currently, changing the dielectric layer material or enhancing the surface contact between the gate dielectric and the c...

Doping can change the band structure of semiconductors, thereby affecting their electrical, optical, and magnetic properties. In this study, we describe the synthesis of two-dimensional (2D) Se-doped Cr2S3 (Se-Cr2S3) nanosheets using the chemical vapor deposition method. In these semiconductor nanosheets, the Se doping concentration can be controll...

The discovery of chiral-induced spin selectivity (CISS) opens up the possibility to manipulate spin orientation without external magnetic fields and enables new spintronic device designs1–4. Although many approaches have been explored for introducing CISS into solid-state materials and devices, the resulting systems so far are often plagued by high...

Two‐dimensional (2D) materials have attracted extensive attention due to their important prospects in electronics and optoelectronics. Synthesizing new 2D materials, characterizing their properties, and developing their applications are still important topics. Herein, the synthesis of α‐GeTe nanoplates on different substrates via the chemical vapor...

The limitation on the spintronic applications of van der Waals layered transition-metal dichalcogenide semiconductors is ascribed to the intrinsic nonmagnetic feature. Recent studies have proved that substitutional doping is an effective route to alter the magnetic properties of two-dimensional transition-metal dichalcogenides (TMDs). However, high...

Two-dimensional (2D) materials with intrinsic magnetism have drawn intense interest for fundamental research and potential application in spintronics and valleytronics. Here we synthesized 2D Cr3Te4 nanosheets with controllable thickness by chemical vapor deposition approach. Reflection magnetic circular dichroism and magneto-transport measurements...

Schottky diode is the fundamental building blocks for modern electronics and optoelectronics. Reducing the semiconductor layer thickness could shrink the vertical size of a Schottky diode, improving its speed and integration density. Here, we demonstrate a new approach to fabricate a Schottky diode with ultrashort physical length approaching atomic...

The controllable growth of two-dimensional (2D) heterostructure arrays is critical for exploring exotic physics and developing novel devices, yet it remains a substantial synthetic challenge. Here we report a rational synthetic strategy to fabricate mosaic heterostructure arrays in monolayer 2D atomic crystals. By using a laser-patterning and an an...

Three-dimensional (3D) nanoporous gold (NPG) shows promising applications in various fields. However, its most common fabrication strategy (i.e., dealloying) faces the problems of high energy consumption, resource waste, the use of corrosive solvent, and residue of the sacrificial component. Here, we report a general bottom-up nanowelding strategy...

Ag nanowire (NW) film is the promising next generation transparent conductor. However, the residual long-chain polyvinylpyrrolidone (PVP, introduced during the synthesis of Ag NWs) layer greatly deteriorates the carrier transport capability of the Ag NW film and as well its long-term stability. Here, we report a one-step I− ion modification strateg...

2D van der Waals heterostructures (vdWHs) and superlattices (SLs) with exotic physical properties and applications for new devices have attracted immense interest. Compared to conventionally bonded heterostructures, the dangling‐bond‐free surface of 2D layered materials allows for the feasible integration of various materials to produce vdWHs witho...

Two-dimensional materials and their heterojunctions have received extensive attention in fundamental and applied research of photonics, electronics, and spintronics. Herein, we stacked SnS 2 , FePS 3 , and graphene (Gr) nanosheets into SnS 2 /FePS 3 /Gr van der Waals heterojunction, which exhibits broadband photoresponse from an ultraviolet region...

2D Semiconductors are promising in the development of next‐generation photodetectors. However, the performances of 2D photodetectors are largely limited by their poor light absorption (due to ultrathin thickness) and small detection range (due to large bandgap). To overcome the limitations, a strain‐plasmonic coupled 2D photodetector is designed by...

Artificially stacked van der Waals heterostructures (vdWH) of two-dimensional (2D) atomic layers have attracted considerable attention due to substantial interactions between different layers. In particular, the strongly bound interlayer exciton (IX) within vdWH offers a platform for exploring fundamental physics as well as innovative device applic...

The accomplishment of nanowelding typically requires the input of high energy, possibly causing appreciable damages to the brittle nanomaterial. Herein, we report an external field (EF, i.e., light, direct current (DC), and alternating current (AC))-strengthened Ostwald nanowelding (ONW) strategy to enable low-temperature nanowelding of Au nanopart...

Recently, two-dimensional (2D) magnetic materials have attracted extensive interest thanks to their potential application as spintronic devices. Albeit bulk magnetic materials are investigated for many years, current developments in nanoscale characterization and device fabrication right down to the 2D limit have unfolded new possibilities. Herein,...

Lithium metal has emerged as the most prospective candidate for the realization of improved battery systems. However, notorious Li dendrite formation and the huge volume effect during cycling critically impair the further practical deployment of Li metal batteries. Herein, we propose hierarchical Ni- and Co-based oxynitride (NiCoO2/CoO/Ni3N) nanoar...

Two-dimensional (2D) semiconductors have attracted intense interest for their unique photophysical properties, including large exciton binding energies and strong gate tunability, which arise from their reduced dimensionality1–5. Despite considerable efforts, a disconnect persists between the fundamental photophysics in pristine 2D semiconductors a...

Thickness‐dependent chemical and physical properties have gained tremendous interest since the emergence of two‐dimensional (2D) materials. Despite attractive prospects, the thickness‐controlled synthesis of ultrathin nanosheets remains an outstanding challenge. Here, a chemical vapor deposition (CVD) route is reported to controllably synthesize hi...

Two-dimensional (2D) magnetic materials have aroused tremendous interest due to the 2D confinement of magnetism and potential applications in spintronic and valleytronic devices. However, most of the currently 2D magnetic materials are achieved by the exfoliation from their bulks, of which the thickness and domain size are difficult to control, lim...

Two-dimensional/one-dimensional (2D/1D) heterostructures as a new type of heterostructure have been studied for their unusual properties and promising applications in electronic and optoelectronic devices. However, the studies of 2D/1D heterostructures are mainly focused on vertical heterostructures, such as MoS 2 nanosheet-carbon nanotubes. The re...

2D materials and the associated heterostructures define an ideal material platform for investigating physical and chemical properties, and exhibiting new functional applications in (opto)electronic devices, electrocatalysis, and energy storage. 2D transition metal dichalcogenides (2D TMDs), as a member of the 2D materials family including 2D semico...

Potassium-ion batteries (PIBs) are of academic and economic significance, but still limited by the lack of highly active electrode materials for de-/intercalation of large-radius K ions. Herein, an interconnected nitrogen/sulfur co-doped carbon nanosheep bundle (N/S-CSB) was proposed as the potassium ions storage material. The rich co-doping of nit...

The two-dimensional transition metal dichalcogenides (TMDs) have attracted intense interest as an atomically thin semiconductor channel for the continued transistor scaling. However, with a dangling bond free surface, it has been a key challenge to reliably integrate high-quality gate dielectrics on TMDs. In particular, the atomic layer deposition...

Phase controllable synthesis of 2D materials is of significance for tuning related electrical, optical, and magnetic properties. Herein, the phase‐controllable synthesis of tetragonal and hexagonal FeTe nanoplates has been realized by a rational control of the Fe/Te ratio in a chemical vapor deposition system. Using density functional theory calcul...

The discovery of intrinsic ferromagnetism in ultrathin two-dimensional van der Waals crystals opens up exciting prospects for exploring magnetism in the ultimate two-dimensional limit. Here, we show that environmentally stable CrSe2 nanosheets can be readily grown on a dangling-bond-free WSe2 substrate with systematically tunable thickness down to...

2D semiconductors have attracted tremendous attention as an atomically thin channel for transistors with superior immunity to short‐channel effects. However, with atomic thin structure, the delicate 2D lattice is not fully compatible with conventional lithography processes that typically involve high‐energy photon/electron radiation and unavoidable...

Numerous efforts have been made to synthesis two-dimensional (2D) atomic semiconductor materials and their heterojunctions owing to diverse novel properties and potential applications in constructing next generation highly compact electronics and optoelectronics devices. However, the intrinsic 2D p-type semiconductor material is still scarce to dat...

2D layered materials typically feature strong in‐plane covalent chemical bonding within each atomic layer and weak out‐of‐plane van der Waals (vdW) interactions between adjacent layers. The non‐bonding nature between neighboring layers naturally results in a vdW gap, in which various foreign species may be inserted without breaking the in‐plane cov...

Recent advances in moiré superlattices and moiré excitons, such as quantum emission arrays, low-energy flat bands, and Mott insulators, have rapidly attracted attention in the fields of optoelectronics, materials, and energy research. The interlayer twist turns into a degree of freedom that alters the properties of the systems of materials, and the...

Vertical transistors—in which the channel length is determined by the thickness of the semiconductor—are of interest in the development of next-generation electronic devices. However, short-channel vertical devices are difficult to fabricate, because the high-energy metallization process typically results in damage to the contact region. Here we sh...

Room-temperature sodium-sulfur batteries (RT-Na-S batteries) are attractive for large-scale energy storage applications owing to their high storage capacity as well as the rich abundance and low cost of the materials. Unfortunately, their practical application is hampered by severe challenges, such as low conductivity of sulfur and its reduced prod...

Van der Waals heterostructures (vdWHs) have attracted tremendous interest owing to the ability to assemble diverse building blocks without the constraints of lattice matching and processing compatibility. However, once assembled, the fabricated vdWHs can hardly be separated into individual building blocks for further manipulation, mainly due to tec...

Two-dimensional (2D) materials1,2 and the associated van der Waals (vdW) heterostructures3–7 have provided great flexibility for integrating distinct atomic layers beyond the traditional limits of lattice-matching requirements, through layer-by-layer mechanical restacking or sequential synthesis. However, the 2D vdW heterostructures explored so far...

Doping can change the intrinsic properties of 2D materials by tuning their electronic structure. In this work, high‐quality 2D In‐doped SnS2 (In‐SnS2) monolayer is reported through chemical vapor transport method and following mechanical cleavage process. The In content of In‐SnS2 is ≈0.9%, and doping results in the downward shift of the Fermi leve...

Two-dimensional (2D) semiconductors have attracted tremendous interest as atomically thin channels that could facilitate continued transistor scaling. However, despite many proof-of-concept demonstrations, the full potential of 2D transistors has yet to be determined. To this end, the fundamental merits and technological limits of 2D transistors ne...

Silver nanowire (Ag NW) films are the promising next-generation flexible, transparent conductors, but their transport properties are greatly deteriorated by the insulating polyvinylpyrrolidone (PVP) layer wrapping on the Ag NWs. Herein, we report a plasma treatment strategy to completely remove the PVP layer and meanwhile limitedly weld the Ag NW f...

The synthesis of 2D WSe2 nanosheets, CoSe‐WSe2 lateral heterostructures. The field‐effect transistors (FETs) of CoSe‐WSe2 lateral heterostructures show satisfactory Ohmic contacts and considerably better FET performance over those with deposited Cr/Au contacts, suggesting the in‐plane metal‐semiconductor junctions may function as improved contacts...

Two-dimensional materials (2DMs) with excellent mechanical, thermal, optical, and catalytic properties have attracted a great deal of attention in recent years. Chemical vapor deposition (CVD) is an important method to realize the synthesis of high-quality 2DMs. In the growth of 2DMs through the CVD method, the substrates play an important role and...

Potassium ion hybrid capacitors (KIHCs) have drawn growing interest owing to their outstanding energy density, power density and excellent cycling stability. However, the large ionic radius of potassium triggers a huge volume change during continuous K⁺ insertion/extraction processes, restricting the development of KIHCs. Here, we report N-doped ca...

Correction for ‘Nitrogen-doped carbon nanotubes as an anode for a highly robust potassium-ion hybrid capacitor’ by Xiuqi Li et al. , Nanoscale Horiz. , 2020, DOI: 10.1039/d0nh00451k.

Silver nanowires (Ag NWs) are promising building blocks for next-generation flexible transparent conductors (TCs). However, the current industrial synthesis method for Ag NWs, i.e., the polyol reduction method, readily produces abundant byproducts of Ag nanoparticles and leaves an insulating polyvinylpyrrolidone (PVP) layer wrapped around the Ag NW...

[This corrects the article DOI: 10.1093/nsr/nwz223.].

Two-dimensional (2D) semiconductors are attractive for electronic devices with atomically thin channels. However, controlling the electronic properties of the 2D materials by incorporating impurity dopants is inherently difficult due to the limited physical space in the atomically thin lattices. Here we show that a solid-state ionic doping approach...

The two‐dimensional (2D) in‐plane (lateral) heterostructures have attracted increasing interest for potential applications in the atomically thin electronics and optoelectronics. While most studies focus on semiconductor‐semiconductor lateral heterostructures with highly similar lattice structures between the constituent components, the synthesis o...

The widespread deployment of lithium ion (Li ⁺ ) batteries with increasing energy density entails a worsening safety concern. Among many contributing factors, the typical polymer separators are plagued with poor thermal stability,limited mechanical strength and lower Li ⁺ transference number, and are prone to catastrophic failure when subjected to...

Lead halide perovskites have attracted increasing interest for their exciting potential in diverse optoelectronic devices. However, their charge transport properties remain elusive, plagued by the issues of excessive contact resistance and large hysteresis in ambient conditions. Here we report a van der Waals integration approach for creating high-...

Mulitipe stoichiometric ratio of two-dimensional (2D) transition metal dichalcogenides (TMDCs) attracted considerable interest for their unique chemical and physical properties. Here we developed a chemical vapor deposition (CVD) method to controllably synthesize ultrathin NiS and NiS2 nanoplates. By tuning the growth temperature and the amounts of...

Palladium diselenide (PdSe2), a stable layered material with pentagonal structure, has attracted extensive interest due to its excellent electrical and optoelectronic performance. Here, we report a reliable process to synthesize PdSe2 via chemical vapor deposition (CVD) method. Through systematic regulation of temperature in the growth process, we...

Monolayer transition metal dichalcogenides (TMDs) have attracted considerable attention as atomically thin semiconductors for the ultimate transistor scaling. For practical applications in integrated electronics, large monolayer single crystals are essential for ensuring consistent electronic properties and high device yield. The TMDs available tod...