Two-dimensional(2D)materials,especially 2D transition metal oxides(TMOs),have garnered significant research attention due to their unique physical and chemical properties and vast potential applications in electronics...Two-dimensional(2D)materials,especially 2D transition metal oxides(TMOs),have garnered significant research attention due to their unique physical and chemical properties and vast potential applications in electronics,optoelectronics,magneto electronics,and energy storage.However,synthesizing 2D TMOs remains a major challenge due to their non-layered lattice structure and the high temperatures required for synthesis.In this study,we report the chemical vapor deposition-based synthesis of high-quality 2D Cr_(2)O_(3) single-crystal nanosheets and investigate their structure and electrical properties.By controlling the growth temperature and carrier gas,we successfully obtained Cr_(2)O_(3) nanosheets with lateral dimensions up to 30μm and a minimum thickness of 4.7 nm.Optical studies,X-ray diffraction,atomic force microscopy,and transmission electron microscopy confirm that the resulting nanosheets are high-quality single crystals.Electrical measurements reveal that charge transport in Cr_(2)O_(3) devices is influenced by both Schottky emission and Poole-Frenkel emission,leading to a non-equilibrium charge conduction state.This systematic synthesis approach provides a reliable route for fabricating 2D TMO single crystals with controlled thickness and offers a platform for investigating charge transfer at electrode-dielectric interfaces,as well as for the design of novel electronic materials and catalysts.展开更多
The two-dimensional(2D)Janus monolayers are promising in spintronic device application due to their enhanced magnetic couplings and Curie temperatures.Van der Waals CrCl_(3) monolayer has been experimentally proved to...The two-dimensional(2D)Janus monolayers are promising in spintronic device application due to their enhanced magnetic couplings and Curie temperatures.Van der Waals CrCl_(3) monolayer has been experimentally proved to have an in-plane magnetic easy axis and a low Curie temperature of 17 K,which will limit its application in spintronic devices.In this work,we propose a new Janus monolayer Cr_(2)Cl_(3)S_(3) based on the first principles calculations.The phonon dispersion and elastic constants confirm that Janus monolayer Cr_(2)Cl_(3)S_(3) is dynamically and mechanically stable.Our Monte Carlo simulation results based on magnetic exchange constants reveal that Janus monolayer Cr_(2)Cl_(3)S_(3) is an intrinsic ferromagnetic semiconductor with TC of 180 K,which is much higher than that of CrCl_(3) due to the enhanced ferromagnetic coupling caused by S substitution.Moreover,the magnetic easy axis of Janus Cr_(2)Cl_(3)S_(3) can be tuned to the perpendicular direction with a large magnetic anisotropy energy(MAE)of 142eV/Cr.Furthermore,the effect of biaxial strain on the magnetic property of Janus monolayer Cr_(2)Cl_(3)S_(3) is evaluated.It is found that the Curie temperature is more robust under tensile strain.This work indicates that the Janus monolayer Cr_(2)Cl_(3)S_(3) presents increased Curie temperature and out-of-plane magnetic easy axis,suggesting greater application potential in 2D spintronic devices.展开更多
Nowadays,there is a growing global demand for high-performance room temperature gas sensing de-vices.In this context,we aim to explore the advancements in two-dimensional(2D)Ti_(3)C_(2)MXene role for toxic NO_(2)gas s...Nowadays,there is a growing global demand for high-performance room temperature gas sensing de-vices.In this context,we aim to explore the advancements in two-dimensional(2D)Ti_(3)C_(2)MXene role for toxic NO_(2)gas sensing at room temperature.The distinctive advantages of 2D Ti_(3)C_(2)MXene,including high electrical conductivity,ample surface area,surface termination groups,and layer structure have garnered significant attention towards NO_(2)gas adsorption.Further,the compatible regularity of Ti_(3)C_(2)MXene at the interface of various semiconductors directed the development of potential room-temperature NO_(2)gas sensing devices.Further,the leveraging gas sensing(selectivity,response,and recovery)characteristics be-come increasing attention on Ti_(3)C_(2)MXene/semiconductor interfaces than pure Ti_(3)C_(2)MXene.Elaborative control on the depletion layer through the Schottky barrier formation distinguished the room tempera-ture NO_(2)gas sensing and led to the evolution of electrophilic NO_(2)gas molecule interaction.Remarkably,the great processability of Ti_(3)C_(2)MXene/semiconductor interface is sensitive to the low detection limit(LOD)of NO_(2)gas at parts per billion(ppb)conditions.On the other hand,this review demonstrates the room temperature optoelectronic NO_(2)gas sensing capabilities of Ti_(3)C_(2)-based composites for emphasiz-ing selectivity and recovery.Interestingly,the Ti_(3)C_(2)MXene/semiconductor composite builds immunity against the atmosphere humidity and achieves stable NO_(2)gas sensing.Finally,we have provided conclu-sions and key points to advance the research on room temperature NO_(2)gas sensing of Ti_(3)C_(2)integrated semiconductors.展开更多
Polar semiconductors,particularly the emerging polar two-dimensional(2D)halide perovskites,have motivated immense interest in diverse photoelectronic devices due to their distinguishing polarizationgenerated photoelec...Polar semiconductors,particularly the emerging polar two-dimensional(2D)halide perovskites,have motivated immense interest in diverse photoelectronic devices due to their distinguishing polarizationgenerated photoelectric effects.However,the constraints on the organic cation's choice are still subject to limitations of polar 2D halide perovskites due to the size of the inorganic pocket between adjacent corner-sharing octahedra.Herein,a mixed spacer cation ordering strategy is employed to assemble a polar 2D halide perovskite NMAMAPb Br_(4)(NMPB,NMA is N-methylbenzene ammonium,MA is methylammonium)with alternating cation in the interlayer space.Driven by the incorporation of a second MA cation,the perovskite layer transformed from a 2D Pb_(7)Br_(24)anionic network with corner-and face-sharing octahedra to a flat 2D PbBr_(4)perovskite networks only with corner-sharing octahedra.In the crystal structure of NMPB,the asymmetric hydrogen-bonding interactions between ordered mixed-spacer cations and 2D perovskite layers give rise to a second harmonic generation response and a large polarization of 1.3μC/cm^(2).More intriguingly,the ordered 2D perovskite networks endow NMPB with excellent self-powered polarization-sensitive detection performance,showing a considerable polarization-related dichroism ratio up to 1.87.The reconstruction of an inorganic framework within a crystal through mixed cation ordering offers a new synthetic tool for templating perovskite lattices with controlled properties,overcoming limitations of conventional cation choice.展开更多
Robust covalent organic frameworks(COFs)with abundant redox-active sites have attracted intense attention for organic cathode materials due to the ordered structure and excellent stability.Herein,a two-dimensional(2D)...Robust covalent organic frameworks(COFs)with abundant redox-active sites have attracted intense attention for organic cathode materials due to the ordered structure and excellent stability.Herein,a two-dimensional(2D)crystalline copper-porphyrin covalent triazine framework(CuBCPP-CTF)was synthesized via polycondensation of 5,15-bis(4-cyanophenyl)porphyrin(H2BCPP)and followed by post-copperization.The integration of copper-porphyrin moieties and triazine linkages provides two kinds of functional sites for outstanding Li+and PF6−ions storage.Electrochemical studies reveal a high discharge capacity of 232 mAh·g^(−1)at 200 mA·g^(−1)and high mid-point voltage(2.77 V vs.Li^(+)/Li),corresponding to an outstanding energy density of 601 Wh·kg^(−1).Density functional theory calculations and ex-situ characterizations disclose the intrinsic bipolar redox mechanism of metalloporphyrin for both PF6−and Li^(+)accommodation and p-type triazine units for PF_(6)^(−)storage.展开更多
Two-dimensional transition metal dichalcogenides(TMDs)have shown great potential for application in the next generation of electronics and optoelectronics due to their atomically thin thickness,tunable band gap,and st...Two-dimensional transition metal dichalcogenides(TMDs)have shown great potential for application in the next generation of electronics and optoelectronics due to their atomically thin thickness,tunable band gap,and strong light-matter interaction.However,their practical application is still limited by challenges such as the constraints of high-temperature synthesis processes,compatibility issues of p-type/n-type doping strategies,and insufficient nanoscale patterning accuracy.Plasma treatment has become a key technology to break through these bottlenecks with its unique advantages such as low-temperature operation capability,generation of highly active reactive species and precise controllability of multiple parameters.This review comprehensively reviews the latest progress in plasma engineering of TMDs(MoS_(2),WS_(2),WSe_(2),etc.)based on a systematic“fundamental process-property modulation-device innovation”framework.The key plasma technologies are highlighted:plasma-enhanced chemical vapor deposition(PECVD)for low-temperature growth,bidirectional doping achieved through active species regulation,atomic layer precision etching,and defect engineering.The regulation mechanism of plasma on the intrinsic properties of materials is systematically analyzed,including electronic structure modification,optical property optimization(such as photoluminescence enhancement)and structural feature evolution.It then reveals how plasma technology promotes device innovation:achieving customizable structures(p-n junctions,sub-10 nanometer channels),optimizing interface properties(reducing contact resistance,integrating high-k dielectrics),and significantly improving the performance of gas sensors,photodetectors and neuromorphic computing systems.Finally,this article looks forward to future research directions,emphasizing that plasma technology is a versatile and indispensable platform for promoting TMDs towards practical applications.展开更多
Inspired by the recently predicted 2D MX_(2)Y_(6)(M=metal element;X=Si/Ge/Sn;Y=S/Se/Te),we explore the possible applications of alkaline earth metal(using magnesium as example)in this family based on the idea of eleme...Inspired by the recently predicted 2D MX_(2)Y_(6)(M=metal element;X=Si/Ge/Sn;Y=S/Se/Te),we explore the possible applications of alkaline earth metal(using magnesium as example)in this family based on the idea of element replacement and valence electron balance.Herein,we report a new family of 2D quaternary compounds,namely MgMX_(2)Y_(6)(M=Ti/Zr/Hf;X=Si/Ge;Y=S/Se/Te)monolayers,with superior kinetic,thermodynamic and mechanical stability.In addition,our results indicate that MgMX_(2)Y_(6)monolayers are all indirect band gap semiconductors with band gap values ranging from 0.870 to 2.500 eV.Moreover,the band edges and optical properties of 2D MgMX_(2)Y_(6)are suitable for constructing multifunctional optoelectronic devices.Furthermore,for comparison,the mechanical,electronic and optical properties of In_(2)X_(2)Y_(6)monolayers have been discussed in detail.The success of introducing Mg into the 2D MX_(2)Y_(6)family indicates that more potential materials,such as Caand Sr-based 2D MX_(2)Y_(6)monolayers,may be discovered in the future.Therefore,this work not only broadens the existing family of 2D semiconductors,but it also provides beneficial results for the future.展开更多
Due to their unique physical and chemical properties,two-dimensional(2D)boron nanosheets have received tremendous research attention and demonstrated substantial value in electronic devices,biomedicine,and energy conv...Due to their unique physical and chemical properties,two-dimensional(2D)boron nanosheets have received tremendous research attention and demonstrated substantial value in electronic devices,biomedicine,and energy conversion.In the preparation of boron nanosheets,compared with the bottom-up synthesis predominantly employed for electronics,the top-down synthesis route offers more facile and scalable production.In this mini-review,we mainly discuss the recent advances in the synthesis of boron nanosheets using the top-down strategy and the relevant applications in energy catalysis.Finally,inspired by our recent works on the novel applications of 2D silicon,we put forward prospects for designing boron nanosheets,providing insights into developing viable techniques for high-performance heterogeneous catalysis.展开更多
Two-dimensional(2D)metals,which are appealing for a plethora of emergent phenomena and technological applications,stand as one of the highly sought-after goals in condensed-matter physics and materials science.In star...Two-dimensional(2D)metals,which are appealing for a plethora of emergent phenomena and technological applications,stand as one of the highly sought-after goals in condensed-matter physics and materials science.In stark contrast to the widely-studied 2D van der Waals(vd W)layered materials in which their weak interlayer interactions facilitate the isolation from their bulk,2D metals are extremely challenging to achieve because of their thermodynamic instability and non-layered nature.In this review,we highlight the recent advances in the reliable production of atomically thin 2D metals,including but not limited to vd W squeezing technique,top-down exfoliation,mechanical pressing,chemical etching,epitaxial growth,and confinement growth.We also present our perspectives and discuss the future opportunities and research directions in this new field.展开更多
It is challenging to reveal the design strategy for strong piezoelectricity nano-materials used in self-powered and smart nano-devices.Through first-principles calculations,an atom-layer-pair effect is found in MoSi_(...It is challenging to reveal the design strategy for strong piezoelectricity nano-materials used in self-powered and smart nano-devices.Through first-principles calculations,an atom-layer-pair effect is found in MoSi_(x)N_(y)R_(z) monolayers with remarkable piezoelectricity.The absolute values of the vertical piezoelectric coefficients have a linear relation with the total electronegativity difference dipole moments.Based on this effect,a promising CrSiN_(4)Sn monolayer is found with the highest piezoelectricity among the above monolayers.The work expands our understanding of the piezoelectric physical mechanism and provides the design strategy for piezoelectric nano-devices.展开更多
We investigate the magnetic and topological properties of Mn_(2)X_(2)Te_(5)(X=Bi,Sb)using first-principles calculations.We find that both Mn_(2)Bi_(2)Te_(5)and Mn_(2)Sb_(2)Te_(5)bilayers exhibit A-type antiferromagnet...We investigate the magnetic and topological properties of Mn_(2)X_(2)Te_(5)(X=Bi,Sb)using first-principles calculations.We find that both Mn_(2)Bi_(2)Te_(5)and Mn_(2)Sb_(2)Te_(5)bilayers exhibit A-type antiferromagnetic order,which can be understood based on the Goodenough-Kanamori-Anderson rules.We further find that an appropriate hole doping can induce a transition from the A-type antiferromagnetic phase to the ferromagnetic phase in these systems,which also experience a transition from a normal insulator to a quantum anomalous Hall phase.Our study thus demonstrates that tunable magnetism and band topology can be achieved in Mn_(2)X_(2)Te_(5),which may be utilized in the design of new functional electronic devices.展开更多
With the development of the Internet,image encryption technology has become critical for network security.Traditional methods often suffer from issues such as insufficient chaos,low randomness in key generation,and po...With the development of the Internet,image encryption technology has become critical for network security.Traditional methods often suffer from issues such as insufficient chaos,low randomness in key generation,and poor encryption efficiency.To enhance performance,this paper proposes a new encryption algorithm designed to optimize parallel processing and adapt to images of varying sizes and colors.The method begins by using SHA-384 to extract the hash value of the plaintext image,which is then processed to determine the chaotic system’s initial value and block size.The image is padded and divided into blocks for further processing.A novel two-dimensional infinite collapses hyperchaotic map(2DICHM)is employed to generate the intra-block scrambling sequence,while an improved variable Joseph traversal sequence is used for inter-block scrambling.After removing the padding,3D forward and backward shift diffusions,controlled by the 2D-ICHM sequences,are applied to the scrambled image,producing the ciphertext.Simulation results demonstrate that the proposed algorithm outperforms others in terms of entropy,anti-noise resilience,correlation coefficient,robustness,and encryption efficiency.展开更多
Two-dimensional materials are widely considered to be highly promising for the development of photodetectors.To improve the performance of these devices,researchers often employ techniques such as defect engineering.H...Two-dimensional materials are widely considered to be highly promising for the development of photodetectors.To improve the performance of these devices,researchers often employ techniques such as defect engineering.Herein,pressure is employed as a clean and novel means to manipulate the structural and physical properties of EuSbTe_(3),an emerging two-dimensional semiconductor.The experimental results demonstrate that the structural phase transformation of EuSbTe_(3)occurs under pressure,with an increase in infrared reflectivity,a band gap closure,and a metallization at pressures.Combined with X-ray diffraction(XRD)and Raman characterizations,it is evident that the pressure-driven transition from semiconductor Pmmn phase to metallic Cmcm phase causes the disappearance of the charge density wave.Furthermore,at a mild pressure,approximately 2 GPa,the maximum photocurrent of EuSbTe_(3)is three times higher than that at ambient condition,suggesting an untapped potential for various practical applications.展开更多
We review experimental and theoretical results on thermal transport in semiconductor nanostructures（multilayer thin films, core/shell and segmented nanowires）, single-and few-layer graphene, hexagonal boron nitride,...We review experimental and theoretical results on thermal transport in semiconductor nanostructures（multilayer thin films, core/shell and segmented nanowires）, single-and few-layer graphene, hexagonal boron nitride, molybdenum disulfide, and black phosphorus. Different possibilities of phonon engineering for optimization of electrical and heat conductions are discussed. The role of the phonon energy spectra modification on the thermal conductivity in semiconductor nanostructures is revealed. The dependence of thermal conductivity in graphene and related two-dimensional（2 D） materials on temperature, flake size, defect concentration, edge roughness, and strain is analyzed.展开更多
The investigation of two-dimensional(2D)materials has advanced into practical device applications,such as cascaded logic stages.However,incompatible electrical properties and inappropriate logic levels remain enormous...The investigation of two-dimensional(2D)materials has advanced into practical device applications,such as cascaded logic stages.However,incompatible electrical properties and inappropriate logic levels remain enormous challenges.In this work,a doping-free strategy is investigated by top gated(TG)MoS_(2) field-effect transistors(FETs)using various metal gates(Au,Cu,Ag,and Al).These metals with different work functions provide a convenient tuning knob for controlling threshold voltage(V_(th))for MoS_(2) FETs.For instance,the Al electrode can create an extra electron doping(n-doping)behavior in the MoS_(2) TG-FETs due to a dipole effect at the gate-dielectric interface.In this work,by achieving matched electrical properties for the load transistor and the driver transistor in an inverter circuit,we successfully demonstrate wafer-scale MoS_(2) inverter arrays with an optimized inverter switching threshold voltage(V_(M))of 1.5 V and a DC voltage gain of 27 at a supply voltage(V_(DD))of 3 V.This work offers a novel scheme for the fabrication of fully integrated multistage logic circuits based on wafer-scale MoS_(2) film.展开更多
Atomically thin two-dimensional （2D） layered materials have potential applications in nanoelectronics, nanophoton- ics, and integrated optoelectronics. Band gap engineering of these 2D semiconductors is critical for...Atomically thin two-dimensional （2D） layered materials have potential applications in nanoelectronics, nanophoton- ics, and integrated optoelectronics. Band gap engineering of these 2D semiconductors is critical for their broad applications in high-performance integrated devices, such as broad-band photodetectors, multi-color light emitting diodes （LEDs）, and high-efficiency photovoltaic devices. In this review, we will summarize the recent progress on the controlled growth of composition modulated atomically thin 2D semiconductor alloys with band gaps tuned in a wide range, as well as their induced applications in broadly tunable optoelectronic components. The band gap engineered 2D semiconductors could open up an exciting opportunity for probing their fundamental physical properties in 2D systems and may find diverse applications in functional electronic/optoelectronic devices.展开更多
Within the(2+1)-dimensional Korteweg–de Vries equation framework,new bilinear B¨acklund transformation and Lax pair are presented based on the binary Bell polynomials and gauge transformation.By introducing an a...Within the(2+1)-dimensional Korteweg–de Vries equation framework,new bilinear B¨acklund transformation and Lax pair are presented based on the binary Bell polynomials and gauge transformation.By introducing an arbitrary functionφ(y),a family of deformed soliton and deformed breather solutions are presented with the improved Hirota’s bilinear method.By choosing the appropriate parameters,their interesting dynamic behaviors are shown in three-dimensional plots.Furthermore,novel rational solutions are generated by taking the limit of the obtained solitons.Additionally,twodimensional(2D)rogue waves(localized in both space and time)on the soliton plane are presented,we refer to them as deformed 2D rogue waves.The obtained deformed 2D rogue waves can be viewed as a 2D analog of the Peregrine soliton on soliton plane,and its evolution process is analyzed in detail.The deformed 2D rogue wave solutions are constructed successfully,which are closely related to the arbitrary functionφ(y).This new idea is also applicable to other nonlinear systems.展开更多
Magnetic order in two-dimensional systems was not supposed to exist at finite temperature.In recent years,the successful preparation of two-dimensional ferromagnetic materials such as CrI_(3),Cr_(2) Ge_(2) Te_(6),and ...Magnetic order in two-dimensional systems was not supposed to exist at finite temperature.In recent years,the successful preparation of two-dimensional ferromagnetic materials such as CrI_(3),Cr_(2) Ge_(2) Te_(6),and Fe_(3)GeTe_(2) opens up a new chapter in the remarkable field of two-dimensional materials.Here,we report on a theoretical analysis of the stability of ferromagnetism in Fe_(3)GeTe_(2).We uncover the mechanism of holding long-range magnetic order and propose a model to estimate the Curie temperature of Fe_(3)GeTe_(2).Our results reveal the essential role of magnetic anisotropy in maintaining the magnetic order of two-dimensional systems.The theoretical method used here can be generalized to future research of other magnetic two-dimensional systems.展开更多
The fascinating Dirac cone in honeycomb graphene,which underlies many unique electronic properties,has inspired the vast endeavors on pursuing new two-dimensional(2D)Dirac materials.Based on the density functional the...The fascinating Dirac cone in honeycomb graphene,which underlies many unique electronic properties,has inspired the vast endeavors on pursuing new two-dimensional(2D)Dirac materials.Based on the density functional theory method,a 2D material Zn3Si2 of honeycomb transition-metal silicide with intrinsic Dirac cones has been predicted.The Zn3Si2 monolayer is dynamically and thermodynamically stable under ambient conditions.Importantly,the Zn3Si2 monolayer is a room-temperature 2D Dirac material with a spin-orbit coupling energy gap of 1.2 meV,which has an intrinsic Dirac cone arising from the special hexagonal lattice structure.Hole doping leads to the spin polarization of the electron,which results in a Dirac half-metal feature with single-spin Dirac fermion.This novel stable 2D transition-metal-silicon-framework material holds promises for electronic device applications in spintronics.展开更多
Layered magnetic materials,such as MnBi_(2)Te_(4),have drawn much attention owing to their potential for realizing twodimensional(2D)magnetism and possible topological states.Recently,FeBi_(2)Te_(4),which is isostruct...Layered magnetic materials,such as MnBi_(2)Te_(4),have drawn much attention owing to their potential for realizing twodimensional(2D)magnetism and possible topological states.Recently,FeBi_(2)Te_(4),which is isostructural to MnBi_(2)Te_(4),has been synthesized in experiments,but its detailed magnetic ordering and band topology have not been clearly understood yet.Here,based on first-principles calculations,we investigate the magnetic and electronic properties of FeBi_(2)Te_(4)in bulk and 2D forms.We show that different from MnBi_(2)Te_(4),the magnetic ground states of bulk,single-layer,and bilayer FeBi_(2)Te_(4)all favor a 120°noncollinear antiferromagnetic ordering,and they are topologically trivial narrow-gap semiconductors.For the bilayer case,we find that a quantum anomalous Hall effect with a unit Chern number is realized in the ferromagnetic state,which may be achieved in experiment by an external magnetic field or by magnetic proximity coupling.Our work clarifies the physical properties of the new material system of FeBi_(2)Te_(4)and reveals it as a potential platform for studying magnetic frustration down to 2D limit as well as quantum anomalous Hall effect.展开更多
基金the support from the National Natural Science Foundation of China(Nos.51991340,62404079,and 62404078)the open research fund of Songshan Lake Materials Laboratory(No.2023SLABFN07)+3 种基金the Natural Science Foundation of Hunan Province(No.2024JJ6135)the Natural Science Foundation of Changsha City(No.kq2402064)the Hunan Key R&D Program Project(No.2022GK2005)the National Key R&D Program of the Ministry of Science and Technology of China(No.2022YFA1203801).
文摘Two-dimensional(2D)materials,especially 2D transition metal oxides(TMOs),have garnered significant research attention due to their unique physical and chemical properties and vast potential applications in electronics,optoelectronics,magneto electronics,and energy storage.However,synthesizing 2D TMOs remains a major challenge due to their non-layered lattice structure and the high temperatures required for synthesis.In this study,we report the chemical vapor deposition-based synthesis of high-quality 2D Cr_(2)O_(3) single-crystal nanosheets and investigate their structure and electrical properties.By controlling the growth temperature and carrier gas,we successfully obtained Cr_(2)O_(3) nanosheets with lateral dimensions up to 30μm and a minimum thickness of 4.7 nm.Optical studies,X-ray diffraction,atomic force microscopy,and transmission electron microscopy confirm that the resulting nanosheets are high-quality single crystals.Electrical measurements reveal that charge transport in Cr_(2)O_(3) devices is influenced by both Schottky emission and Poole-Frenkel emission,leading to a non-equilibrium charge conduction state.This systematic synthesis approach provides a reliable route for fabricating 2D TMO single crystals with controlled thickness and offers a platform for investigating charge transfer at electrode-dielectric interfaces,as well as for the design of novel electronic materials and catalysts.
基金the National Natural Science Foundation of China(Grant No.12104234)the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BK20210578,20KJB140004,and JSSCBS20210513)+4 种基金Y Pu acknowledges the National Natural Science Foundation of China(Grant Nos.61874060,U1932159,and 61911530220)Jiangsu Specially-Appointed Professor Program,the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BK20181388 and 19KJA180007)the Overseas Researcher Innovation Program of Nanjing,NUPTSF(Grant No.NY217118)F Li Acknowledges the Natural Science Fund for Colleges and Universities in Jiangsu Province,China(Grant No.21KJD140005)the National Natural Science Foundation of China(Grant No.12304085).
文摘The two-dimensional(2D)Janus monolayers are promising in spintronic device application due to their enhanced magnetic couplings and Curie temperatures.Van der Waals CrCl_(3) monolayer has been experimentally proved to have an in-plane magnetic easy axis and a low Curie temperature of 17 K,which will limit its application in spintronic devices.In this work,we propose a new Janus monolayer Cr_(2)Cl_(3)S_(3) based on the first principles calculations.The phonon dispersion and elastic constants confirm that Janus monolayer Cr_(2)Cl_(3)S_(3) is dynamically and mechanically stable.Our Monte Carlo simulation results based on magnetic exchange constants reveal that Janus monolayer Cr_(2)Cl_(3)S_(3) is an intrinsic ferromagnetic semiconductor with TC of 180 K,which is much higher than that of CrCl_(3) due to the enhanced ferromagnetic coupling caused by S substitution.Moreover,the magnetic easy axis of Janus Cr_(2)Cl_(3)S_(3) can be tuned to the perpendicular direction with a large magnetic anisotropy energy(MAE)of 142eV/Cr.Furthermore,the effect of biaxial strain on the magnetic property of Janus monolayer Cr_(2)Cl_(3)S_(3) is evaluated.It is found that the Curie temperature is more robust under tensile strain.This work indicates that the Janus monolayer Cr_(2)Cl_(3)S_(3) presents increased Curie temperature and out-of-plane magnetic easy axis,suggesting greater application potential in 2D spintronic devices.
基金supported by the National Research Foundation of Korea(NRF)Grant funded by the Korea government(MSIT)(No.2019R1A2C1008746).
文摘Nowadays,there is a growing global demand for high-performance room temperature gas sensing de-vices.In this context,we aim to explore the advancements in two-dimensional(2D)Ti_(3)C_(2)MXene role for toxic NO_(2)gas sensing at room temperature.The distinctive advantages of 2D Ti_(3)C_(2)MXene,including high electrical conductivity,ample surface area,surface termination groups,and layer structure have garnered significant attention towards NO_(2)gas adsorption.Further,the compatible regularity of Ti_(3)C_(2)MXene at the interface of various semiconductors directed the development of potential room-temperature NO_(2)gas sensing devices.Further,the leveraging gas sensing(selectivity,response,and recovery)characteristics be-come increasing attention on Ti_(3)C_(2)MXene/semiconductor interfaces than pure Ti_(3)C_(2)MXene.Elaborative control on the depletion layer through the Schottky barrier formation distinguished the room tempera-ture NO_(2)gas sensing and led to the evolution of electrophilic NO_(2)gas molecule interaction.Remarkably,the great processability of Ti_(3)C_(2)MXene/semiconductor interface is sensitive to the low detection limit(LOD)of NO_(2)gas at parts per billion(ppb)conditions.On the other hand,this review demonstrates the room temperature optoelectronic NO_(2)gas sensing capabilities of Ti_(3)C_(2)-based composites for emphasiz-ing selectivity and recovery.Interestingly,the Ti_(3)C_(2)MXene/semiconductor composite builds immunity against the atmosphere humidity and achieves stable NO_(2)gas sensing.Finally,we have provided conclu-sions and key points to advance the research on room temperature NO_(2)gas sensing of Ti_(3)C_(2)integrated semiconductors.
基金supported by the National Natural Science Foundation of China(Nos.22193042,22125110,22075285,52473283,21921001,U21A2069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(No.ZDBS-LY-SLH024)the Youth Innovation Promotion of Chinese Academy of Sciences(No.2020307)。
文摘Polar semiconductors,particularly the emerging polar two-dimensional(2D)halide perovskites,have motivated immense interest in diverse photoelectronic devices due to their distinguishing polarizationgenerated photoelectric effects.However,the constraints on the organic cation's choice are still subject to limitations of polar 2D halide perovskites due to the size of the inorganic pocket between adjacent corner-sharing octahedra.Herein,a mixed spacer cation ordering strategy is employed to assemble a polar 2D halide perovskite NMAMAPb Br_(4)(NMPB,NMA is N-methylbenzene ammonium,MA is methylammonium)with alternating cation in the interlayer space.Driven by the incorporation of a second MA cation,the perovskite layer transformed from a 2D Pb_(7)Br_(24)anionic network with corner-and face-sharing octahedra to a flat 2D PbBr_(4)perovskite networks only with corner-sharing octahedra.In the crystal structure of NMPB,the asymmetric hydrogen-bonding interactions between ordered mixed-spacer cations and 2D perovskite layers give rise to a second harmonic generation response and a large polarization of 1.3μC/cm^(2).More intriguingly,the ordered 2D perovskite networks endow NMPB with excellent self-powered polarization-sensitive detection performance,showing a considerable polarization-related dichroism ratio up to 1.87.The reconstruction of an inorganic framework within a crystal through mixed cation ordering offers a new synthetic tool for templating perovskite lattices with controlled properties,overcoming limitations of conventional cation choice.
基金supported by the National Natural Science Foundation of China(Nos.22261132512,22235001,22175020,and 22131005)Guizhou Provincial Key Laboratory Platform Project(No.ZSYS[2025]008)+1 种基金Talent Program of Guizhou University(No.[2024]11)Xiaomi Young Scholar Program,and University of Science and Technology Beijing.
文摘Robust covalent organic frameworks(COFs)with abundant redox-active sites have attracted intense attention for organic cathode materials due to the ordered structure and excellent stability.Herein,a two-dimensional(2D)crystalline copper-porphyrin covalent triazine framework(CuBCPP-CTF)was synthesized via polycondensation of 5,15-bis(4-cyanophenyl)porphyrin(H2BCPP)and followed by post-copperization.The integration of copper-porphyrin moieties and triazine linkages provides two kinds of functional sites for outstanding Li+and PF6−ions storage.Electrochemical studies reveal a high discharge capacity of 232 mAh·g^(−1)at 200 mA·g^(−1)and high mid-point voltage(2.77 V vs.Li^(+)/Li),corresponding to an outstanding energy density of 601 Wh·kg^(−1).Density functional theory calculations and ex-situ characterizations disclose the intrinsic bipolar redox mechanism of metalloporphyrin for both PF6−and Li^(+)accommodation and p-type triazine units for PF_(6)^(−)storage.
基金supported by the National Science Foundation of China(Nos.62304151,62204170,and 62474124)the Natural Science Foundation of Tianjin(No.24JCQNJC00520)+3 种基金the China Postdoctoral Science Foundation(No.2023M742585)the Open Project of State Key Laboratory of Transducer Technology(No.SKT2208)the open research of Songshan Lake Materials Laboratory(No.2023SLABFK07)the State Key Laboratory of Fluid Power and Mechatronic Systems(No.GZKF-202327).
文摘Two-dimensional transition metal dichalcogenides(TMDs)have shown great potential for application in the next generation of electronics and optoelectronics due to their atomically thin thickness,tunable band gap,and strong light-matter interaction.However,their practical application is still limited by challenges such as the constraints of high-temperature synthesis processes,compatibility issues of p-type/n-type doping strategies,and insufficient nanoscale patterning accuracy.Plasma treatment has become a key technology to break through these bottlenecks with its unique advantages such as low-temperature operation capability,generation of highly active reactive species and precise controllability of multiple parameters.This review comprehensively reviews the latest progress in plasma engineering of TMDs(MoS_(2),WS_(2),WSe_(2),etc.)based on a systematic“fundamental process-property modulation-device innovation”framework.The key plasma technologies are highlighted:plasma-enhanced chemical vapor deposition(PECVD)for low-temperature growth,bidirectional doping achieved through active species regulation,atomic layer precision etching,and defect engineering.The regulation mechanism of plasma on the intrinsic properties of materials is systematically analyzed,including electronic structure modification,optical property optimization(such as photoluminescence enhancement)and structural feature evolution.It then reveals how plasma technology promotes device innovation:achieving customizable structures(p-n junctions,sub-10 nanometer channels),optimizing interface properties(reducing contact resistance,integrating high-k dielectrics),and significantly improving the performance of gas sensors,photodetectors and neuromorphic computing systems.Finally,this article looks forward to future research directions,emphasizing that plasma technology is a versatile and indispensable platform for promoting TMDs towards practical applications.
基金supported by the National Natural Science Foundation of China (Grant No. 61974049, 62222404 61974050)National Key Research and Development Plan of China (Grant No. 2021YFB3601200)
文摘Inspired by the recently predicted 2D MX_(2)Y_(6)(M=metal element;X=Si/Ge/Sn;Y=S/Se/Te),we explore the possible applications of alkaline earth metal(using magnesium as example)in this family based on the idea of element replacement and valence electron balance.Herein,we report a new family of 2D quaternary compounds,namely MgMX_(2)Y_(6)(M=Ti/Zr/Hf;X=Si/Ge;Y=S/Se/Te)monolayers,with superior kinetic,thermodynamic and mechanical stability.In addition,our results indicate that MgMX_(2)Y_(6)monolayers are all indirect band gap semiconductors with band gap values ranging from 0.870 to 2.500 eV.Moreover,the band edges and optical properties of 2D MgMX_(2)Y_(6)are suitable for constructing multifunctional optoelectronic devices.Furthermore,for comparison,the mechanical,electronic and optical properties of In_(2)X_(2)Y_(6)monolayers have been discussed in detail.The success of introducing Mg into the 2D MX_(2)Y_(6)family indicates that more potential materials,such as Caand Sr-based 2D MX_(2)Y_(6)monolayers,may be discovered in the future.Therefore,this work not only broadens the existing family of 2D semiconductors,but it also provides beneficial results for the future.
基金supported by the National Natural Science Foundation of China(No.52372233)the Fundamental Research Funds for the Central Universities(No.226-2022-00200),China.
文摘Due to their unique physical and chemical properties,two-dimensional(2D)boron nanosheets have received tremendous research attention and demonstrated substantial value in electronic devices,biomedicine,and energy conversion.In the preparation of boron nanosheets,compared with the bottom-up synthesis predominantly employed for electronics,the top-down synthesis route offers more facile and scalable production.In this mini-review,we mainly discuss the recent advances in the synthesis of boron nanosheets using the top-down strategy and the relevant applications in energy catalysis.Finally,inspired by our recent works on the novel applications of 2D silicon,we put forward prospects for designing boron nanosheets,providing insights into developing viable techniques for high-performance heterogeneous catalysis.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(CAS)(Grant No.XDB0470101)the National Natural Science Foundation of China(Grant Nos.12422402,62488201,12274447,62204166,and 52325201)the National Key Research and Development Program of China(Grant Nos.2021YFA1202900 and 2023YFA1407000)。
文摘Two-dimensional(2D)metals,which are appealing for a plethora of emergent phenomena and technological applications,stand as one of the highly sought-after goals in condensed-matter physics and materials science.In stark contrast to the widely-studied 2D van der Waals(vd W)layered materials in which their weak interlayer interactions facilitate the isolation from their bulk,2D metals are extremely challenging to achieve because of their thermodynamic instability and non-layered nature.In this review,we highlight the recent advances in the reliable production of atomically thin 2D metals,including but not limited to vd W squeezing technique,top-down exfoliation,mechanical pressing,chemical etching,epitaxial growth,and confinement growth.We also present our perspectives and discuss the future opportunities and research directions in this new field.
基金supported by the National Natural Science Foundation of China(Grant No.11474123).
文摘It is challenging to reveal the design strategy for strong piezoelectricity nano-materials used in self-powered and smart nano-devices.Through first-principles calculations,an atom-layer-pair effect is found in MoSi_(x)N_(y)R_(z) monolayers with remarkable piezoelectricity.The absolute values of the vertical piezoelectric coefficients have a linear relation with the total electronegativity difference dipole moments.Based on this effect,a promising CrSiN_(4)Sn monolayer is found with the highest piezoelectricity among the above monolayers.The work expands our understanding of the piezoelectric physical mechanism and provides the design strategy for piezoelectric nano-devices.
基金Project supported by the National Natural Science Foundation of China(Grants Nos.12174098 and 12574262)the Major Fundamental Research Program of Hunan Province(Grants No.2025ZYJ004)the State Key Laboratory of Powder Metallurgy,Central South University,China。
文摘We investigate the magnetic and topological properties of Mn_(2)X_(2)Te_(5)(X=Bi,Sb)using first-principles calculations.We find that both Mn_(2)Bi_(2)Te_(5)and Mn_(2)Sb_(2)Te_(5)bilayers exhibit A-type antiferromagnetic order,which can be understood based on the Goodenough-Kanamori-Anderson rules.We further find that an appropriate hole doping can induce a transition from the A-type antiferromagnetic phase to the ferromagnetic phase in these systems,which also experience a transition from a normal insulator to a quantum anomalous Hall phase.Our study thus demonstrates that tunable magnetism and band topology can be achieved in Mn_(2)X_(2)Te_(5),which may be utilized in the design of new functional electronic devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62105004 and 52174141)the College Student Innovation and Entrepreneurship Fund Project(Grant No.202210361053)+4 种基金Anhui Mining Machinery and Electrical Equipment Coordination Innovation Center,Anhui University of Science&Technology(Grant No.KSJD202304)the Anhui Province Digital Agricultural Engineering Technology Research Center Open Project(Grant No.AHSZNYGC-ZXKF021)the Talent Recruitment Special Fund of Anhui University of Science and Technology(Grant No.2024yjrc175)the Graduate Innovation Fund Project of Anhui University of Science and Technology(Grant Nos.2024cx2067,2024cx2107,and 2024cx2064)Seed Support Project for Postgraduate Innovation,Entrepreneurship and Practice at Anhui University of Science and Technology(Grant No.2024cxcysj084).
文摘With the development of the Internet,image encryption technology has become critical for network security.Traditional methods often suffer from issues such as insufficient chaos,low randomness in key generation,and poor encryption efficiency.To enhance performance,this paper proposes a new encryption algorithm designed to optimize parallel processing and adapt to images of varying sizes and colors.The method begins by using SHA-384 to extract the hash value of the plaintext image,which is then processed to determine the chaotic system’s initial value and block size.The image is padded and divided into blocks for further processing.A novel two-dimensional infinite collapses hyperchaotic map(2DICHM)is employed to generate the intra-block scrambling sequence,while an improved variable Joseph traversal sequence is used for inter-block scrambling.After removing the padding,3D forward and backward shift diffusions,controlled by the 2D-ICHM sequences,are applied to the scrambled image,producing the ciphertext.Simulation results demonstrate that the proposed algorithm outperforms others in terms of entropy,anti-noise resilience,correlation coefficient,robustness,and encryption efficiency.
基金financially supported by the National Natural Science Foundation of China(No.U2130116)Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments(MFree),China(No.22dz2260800)Shanghai Science and Technology Committee,China(No.22JC1410300)。
文摘Two-dimensional materials are widely considered to be highly promising for the development of photodetectors.To improve the performance of these devices,researchers often employ techniques such as defect engineering.Herein,pressure is employed as a clean and novel means to manipulate the structural and physical properties of EuSbTe_(3),an emerging two-dimensional semiconductor.The experimental results demonstrate that the structural phase transformation of EuSbTe_(3)occurs under pressure,with an increase in infrared reflectivity,a band gap closure,and a metallization at pressures.Combined with X-ray diffraction(XRD)and Raman characterizations,it is evident that the pressure-driven transition from semiconductor Pmmn phase to metallic Cmcm phase causes the disappearance of the charge density wave.Furthermore,at a mild pressure,approximately 2 GPa,the maximum photocurrent of EuSbTe_(3)is three times higher than that at ambient condition,suggesting an untapped potential for various practical applications.
基金Project supported by the Republic of Moldova through the projects 15.817.02.29F and 17.80013.16.02.04/Ua
文摘We review experimental and theoretical results on thermal transport in semiconductor nanostructures（multilayer thin films, core/shell and segmented nanowires）, single-and few-layer graphene, hexagonal boron nitride, molybdenum disulfide, and black phosphorus. Different possibilities of phonon engineering for optimization of electrical and heat conductions are discussed. The role of the phonon energy spectra modification on the thermal conductivity in semiconductor nanostructures is revealed. The dependence of thermal conductivity in graphene and related two-dimensional（2 D） materials on temperature, flake size, defect concentration, edge roughness, and strain is analyzed.
基金supported by the National Key Research and Development Program (No.2016YFA0203900)Innovation Program of Shanghai Municipal Education Commission (No.2021–01–07–00–07-E00077)+1 种基金Shanghai Municipal Science and Technology Commission (No.21DZ1100900)National Natural Science Foundation of China (Nos.51802041,61904032,and 61874154)。
文摘The investigation of two-dimensional(2D)materials has advanced into practical device applications,such as cascaded logic stages.However,incompatible electrical properties and inappropriate logic levels remain enormous challenges.In this work,a doping-free strategy is investigated by top gated(TG)MoS_(2) field-effect transistors(FETs)using various metal gates(Au,Cu,Ag,and Al).These metals with different work functions provide a convenient tuning knob for controlling threshold voltage(V_(th))for MoS_(2) FETs.For instance,the Al electrode can create an extra electron doping(n-doping)behavior in the MoS_(2) TG-FETs due to a dipole effect at the gate-dielectric interface.In this work,by achieving matched electrical properties for the load transistor and the driver transistor in an inverter circuit,we successfully demonstrate wafer-scale MoS_(2) inverter arrays with an optimized inverter switching threshold voltage(V_(M))of 1.5 V and a DC voltage gain of 27 at a supply voltage(V_(DD))of 3 V.This work offers a novel scheme for the fabrication of fully integrated multistage logic circuits based on wafer-scale MoS_(2) film.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11374092,61474040,61574054,and 61505051)the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province,Chinathe Science and Technology Department of Hunan Province,China(Grant No.2014FJ2001)
文摘Atomically thin two-dimensional （2D） layered materials have potential applications in nanoelectronics, nanophoton- ics, and integrated optoelectronics. Band gap engineering of these 2D semiconductors is critical for their broad applications in high-performance integrated devices, such as broad-band photodetectors, multi-color light emitting diodes （LEDs）, and high-efficiency photovoltaic devices. In this review, we will summarize the recent progress on the controlled growth of composition modulated atomically thin 2D semiconductor alloys with band gaps tuned in a wide range, as well as their induced applications in broadly tunable optoelectronic components. The band gap engineered 2D semiconductors could open up an exciting opportunity for probing their fundamental physical properties in 2D systems and may find diverse applications in functional electronic/optoelectronic devices.
基金Project supported by the National Natural Scinece Foundation of China(Grant Nos.11671219,11871446,12071304,and 12071451).
文摘Within the(2+1)-dimensional Korteweg–de Vries equation framework,new bilinear B¨acklund transformation and Lax pair are presented based on the binary Bell polynomials and gauge transformation.By introducing an arbitrary functionφ(y),a family of deformed soliton and deformed breather solutions are presented with the improved Hirota’s bilinear method.By choosing the appropriate parameters,their interesting dynamic behaviors are shown in three-dimensional plots.Furthermore,novel rational solutions are generated by taking the limit of the obtained solitons.Additionally,twodimensional(2D)rogue waves(localized in both space and time)on the soliton plane are presented,we refer to them as deformed 2D rogue waves.The obtained deformed 2D rogue waves can be viewed as a 2D analog of the Peregrine soliton on soliton plane,and its evolution process is analyzed in detail.The deformed 2D rogue wave solutions are constructed successfully,which are closely related to the arbitrary functionφ(y).This new idea is also applicable to other nonlinear systems.
基金Project supported by the Fundamental Research Funds for the Central Universities,China(Grant No.XJS200503)the Post-Doctoral Research Project of Shaanxi Province,China。
文摘Magnetic order in two-dimensional systems was not supposed to exist at finite temperature.In recent years,the successful preparation of two-dimensional ferromagnetic materials such as CrI_(3),Cr_(2) Ge_(2) Te_(6),and Fe_(3)GeTe_(2) opens up a new chapter in the remarkable field of two-dimensional materials.Here,we report on a theoretical analysis of the stability of ferromagnetism in Fe_(3)GeTe_(2).We uncover the mechanism of holding long-range magnetic order and propose a model to estimate the Curie temperature of Fe_(3)GeTe_(2).Our results reveal the essential role of magnetic anisotropy in maintaining the magnetic order of two-dimensional systems.The theoretical method used here can be generalized to future research of other magnetic two-dimensional systems.
基金the National Natural Science Foundation of China(Grant Nos.11674136 and 11564022)Yunnan Province for Recruiting High-Caliber Technological Talents,China(Grant No.1097816002)+3 种基金Reserve Talents for Yunnan Young and Middle-aged Academic and Technical Leaders,China(Grant No.2017HB010)the Academic Qinglan Project of KUST(Grant No.1407840010)the Analysis and Testing Fund of KUST(Grant No.2017M20162230010)the High-level Talents of KUST(Grant No.1411909425)。
文摘The fascinating Dirac cone in honeycomb graphene,which underlies many unique electronic properties,has inspired the vast endeavors on pursuing new two-dimensional(2D)Dirac materials.Based on the density functional theory method,a 2D material Zn3Si2 of honeycomb transition-metal silicide with intrinsic Dirac cones has been predicted.The Zn3Si2 monolayer is dynamically and thermodynamically stable under ambient conditions.Importantly,the Zn3Si2 monolayer is a room-temperature 2D Dirac material with a spin-orbit coupling energy gap of 1.2 meV,which has an intrinsic Dirac cone arising from the special hexagonal lattice structure.Hole doping leads to the spin polarization of the electron,which results in a Dirac half-metal feature with single-spin Dirac fermion.This novel stable 2D transition-metal-silicon-framework material holds promises for electronic device applications in spintronics.
基金funding support from the Singapore MOE Ac RF 308 Tier 2(Grant No.T2EP50220-0026)funding support from Shandong Provincial Natural Science Foundation(Grant No.ZR2023QA012)+3 种基金the Special Fund-ing in the Project of Qilu Young Scholar Program of Shandong Universityfunding support from Australian Research Council Future Fellowship(Grant No.FT220100290)funding support from the AINSE postgraduate awardfunding support from the Research and Development Administration Office at the University of Macao(Grants Nos.MYRG2022-00088-IAPME and SRG2021-00003-IAPME)。
文摘Layered magnetic materials,such as MnBi_(2)Te_(4),have drawn much attention owing to their potential for realizing twodimensional(2D)magnetism and possible topological states.Recently,FeBi_(2)Te_(4),which is isostructural to MnBi_(2)Te_(4),has been synthesized in experiments,but its detailed magnetic ordering and band topology have not been clearly understood yet.Here,based on first-principles calculations,we investigate the magnetic and electronic properties of FeBi_(2)Te_(4)in bulk and 2D forms.We show that different from MnBi_(2)Te_(4),the magnetic ground states of bulk,single-layer,and bilayer FeBi_(2)Te_(4)all favor a 120°noncollinear antiferromagnetic ordering,and they are topologically trivial narrow-gap semiconductors.For the bilayer case,we find that a quantum anomalous Hall effect with a unit Chern number is realized in the ferromagnetic state,which may be achieved in experiment by an external magnetic field or by magnetic proximity coupling.Our work clarifies the physical properties of the new material system of FeBi_(2)Te_(4)and reveals it as a potential platform for studying magnetic frustration down to 2D limit as well as quantum anomalous Hall effect.
