One-dimensional nanostructures(1D)with short ion diffusion distance and fast ion transport path are excellent for lithium-ion batteries(LIBs). However, the nature of layered transition metal dichalcogenides makes it d...One-dimensional nanostructures(1D)with short ion diffusion distance and fast ion transport path are excellent for lithium-ion batteries(LIBs). However, the nature of layered transition metal dichalcogenides makes it difficult to form 1D nanohybrids. Here, the MoTe_(2) nanorods with an average diameter of 100-200 nm and length of 1-3 μm encapsulated by reduced graphene oxide(MoTe_(2)/rGO) have been fabricated via in-situ reaction of GO coated Mo_3O_(10)(C_(2)H_(10)N_(2)) nanowires with Te under Ar/H_(2) atmosphere. When applied as anode of LIBs, the Mo Te_(2)/r GO delivers a high reversible capacity(637 m A h g^(-1) after 100 cycles at 0.2 A g^(-1)), good rate capability(374 m A h g^(-1) at 2 A g^(-1)) and excellent stability(360 m A h g^(-1) after 200 cycles at 0.5 A g^(-1)), which surpasses bare Mo Te2 nanorods and bulk Mo Te2 crystallite. Furthermore, a lithium-ion full cell constructed by coupling Mo Te2/r GO anode and LiCoO_(2) cathode shows a capacity of 105 m A h g^(-1) at 0.1 C. The enhanced performance mainly benefits from the advantages of 1D nanostructure, and meanwhile the r GO thin layers are able to improve the conductivity and maintain the structural stability. This work provides a simple pathway for the synthesis of 1D TMDs nanostructures for energy storage and conversion.展开更多
The two-dimensional(2D)material-based thermal switch is attracting attention due to its novel applications,such as energy conversion and thermal management,in nanoscale devices.In this paper,we observed that the rever...The two-dimensional(2D)material-based thermal switch is attracting attention due to its novel applications,such as energy conversion and thermal management,in nanoscale devices.In this paper,we observed that the reversible 2H–1T′phase transition in MoTe_(2)is associated with about a fourfold/tenfold change in thermal conductivity along the X/Y direction by using first-principles calculations.This phenomenon can be profoundly understood by comparing the Mo–Te bonding strength between the two phases.The 2H-MoTe_(2)has one stronger bonding type,while 1T′-MoTe_(2)has three weaker types of bonds,suggesting bonding inhomogeneity in 1T′-MoTe_(2).Meanwhile,the bonding inhomogeneity can induce more scattering of vibration modes.The weaker bonding indicates a softer structure,resulting in lower phonon group velocity,a shorter phonon relaxation lifetime and larger Gr¨uneisen constants.The impact caused by the 2H to 1T′phase transition in MoTe_(2)hinders the propagation of phonons,thereby reducing thermal conductivity.Our study describes the possibility for the provision of the MoTe_(2)-based controllable and reversible thermal switch device.展开更多
Spin orbit torques(SOTs)in ferromagnet/heavy-metal heterostructures have provided great opportunities for efficient manipulation of spintronic devices.However,deterministically field-free switching of perpendicular ma...Spin orbit torques(SOTs)in ferromagnet/heavy-metal heterostructures have provided great opportunities for efficient manipulation of spintronic devices.However,deterministically field-free switching of perpendicular magnetization with SOTs is forbidden because of the global two-fold rotational symmetry in conventional heavy-metal such as Pt.Here,we engineer the interface of Pt/Ni heterostructures by inserting a monolayer MoTe_(2)with low crystal symmetry.It is demonstrated that the spin orbit efficiency,as well as the out-of-plane magnetic anisotropy and the Gilbert damping of Ni are enhanced,due to the effect of orbital hybridization and the increased spin scatting at the interface induced by MoTe_(2).Particularly,an out-of-plane damping-like torque is observed when the current is applied perpendicular to the mirror plane of the MoTe_(2)crystal,which is attributed to the interfacial inversion symmetry breaking of the system.Our work provides an effective route for engineering the SOT in Pt-based heterostructures,and offers potential opportunities for van der Waals interfaces in spintronic devices.展开更多
The direct synthesis of hydrogen peroxide(H_(2)O_(2))via a two‐electron oxygen reduction reaction(2e‐ORR)in acidic media has emerged as a green process for the production of this valuable chemical.However,such an ap...The direct synthesis of hydrogen peroxide(H_(2)O_(2))via a two‐electron oxygen reduction reaction(2e‐ORR)in acidic media has emerged as a green process for the production of this valuable chemical.However,such an approach employs expensive noble‐metal‐based electrocatalysts,which severely undermines its feasibility when implemented on an industrial scale.Herein,based on density functional theory computations and microkinetic modeling,we demonstrate that a novel two‐dimensional(2D)material,namely a 1T′‐MoTe_(2)monolayer,can serve as an efficient non‐precious electrocatalyst to facilitate the 2e‐ORR.The 1T′‐MoTe_(2)monolayer is a stable 2D crystal that can be easily produced through exfoliation techniques.The surface‐exposed Te sites of the 1T′‐MoTe_(2)monolayer exhibit a favorable OOH*binding energy of 4.24 eV,resulting in a rather high basal plane activity toward the 2e‐ORR.Importantly,kinetic computations indicate that the 1T'‐MoTe_(2)monolayer preferentially promotes the formation of H_(2)O_(2)over the competing four‐electron ORR step.These desirable characteristics render 1T′‐MoTe_(2)a promising candidate for catalyzing the electrochemical reduction of O_(2)to H_(2)O_(2).展开更多
Thin-film lithium niobate(TFLN)is considered a crucial platform in next-generation integrated optoelectronics due to its excellent optical properties.Photodetectors are essential components for constructing fully func...Thin-film lithium niobate(TFLN)is considered a crucial platform in next-generation integrated optoelectronics due to its excellent optical properties.Photodetectors are essential components for constructing fully functional photonic circuits.However,due to the low electrical conductivity and weak light absorption,TFLN cannot be directly used for fabricating photodetectors.In this study,we proposed and demonstrated a high-performance MoTe_(2)/TFLN heterostructure integrated Schottky photodetector operating at telecommunication wavelengths(1310 nm and 1550 nm).This structure enhances the photovoltaic effect by bending MoTe_(2)at the edge of one electrode,thereby achieving self-powered operation.At a wavelength of 1310 nm,the photodetector achieves a self-powered responsivity of 70 mA/W,which is among the highest for waveguide-integrated photodetectors.Additionally,due to the strong rectification effect of the Schottky junction,the photodetector exhibits an extremely low dark current of only 25 pA at−0.5 V bias voltage.The on/off ratios reach 2.63104 at 0 V and 4.13104 at−0.5 V bias.The self-powered response times were measured,showing fast response and recovery times of 160μs and 169μs,respectively.展开更多
Two-dimensional(2D)MoTe_(2) shows great potential for future semiconductor devices,but the lab-to-fab transition is still in its preliminary stage due to the constraints in the crystal growth level.Currently,the chemi...Two-dimensional(2D)MoTe_(2) shows great potential for future semiconductor devices,but the lab-to-fab transition is still in its preliminary stage due to the constraints in the crystal growth level.Currently,the chemical vapor deposition growth of 2D MoTe_(2) primarily relies on the tellurization process of Mo-source precursor(MSP).However,the target product 2H-MoTe_(2) from Mo precursor suffers from long growth time and suboptimal crystal quality,and MoO_(x) precursor confronts the dilemma of unclear growth mechanism and inconsistent growth products.Here,we developed magnetron-sputtered MoO_(3) film for fast and high-mobility 2H-MoTe_(2) growth.The solid-to-solid phase transition growth mechanism of 2D MoTe_(2) from Mo and MoO_(x) precursor was first experimentally unified,and the effect mechanism of MSPs on 2D MoTe_(2) growth was systematically elucidated.Compared with Mo and MoO2,the MoO_(3) precursor has the least Mo-unit lattice deformation and exhibits the optimal crystal quality of growth products.Meanwhile,the lowest Gibbs free energy change of the chemical reaction results in an impressive 2HMoTe_(2) growth rate of 8.07 mm/min.The constructed 2H-MoTe_(2) field-effect transistor array from MoO_(3) precursor showcases record-high hole mobility of 85 cm^(2)·V^(-1)·s^(-1),competitive on-off ratio of 3×10^(4),and outstanding uniformity.This scalable method not only offers efficiency but also aligns with industry standards,making it a promising guideline for diverse 2D material preparation towards real-world applications.展开更多
Two-dimensional(2D)materials hold immense potential for next-generation information devices due to their ambipolar transport and tunable electronic states.However,conventional electric-field-driven architectures suffe...Two-dimensional(2D)materials hold immense potential for next-generation information devices due to their ambipolar transport and tunable electronic states.However,conventional electric-field-driven architectures suffer from inherent carrier-type degeneracy:Electrons and holes generate unidirectional currents,leading to ambiguous state overlaps in multi-level operation.Here,we demonstrate that surface acoustic waves(SAWs)break this symmetry in optically reconfigurable MoTe_(2)/h-BN heterostructures.SAWs induce type-II band modulation in the heterostructure and spatially separate electrons and holes into distinct valleys,enabling bidirectional acoustoelectric currents,whose polarity reverses with carrier type,controlled dynamically via ultraviolet(UV)illumination and gating.Leveraging this mechanism,we realize an 8-state memory device where SAW-driven readout currents changed between positive and negative polarities,achieving enhanced inter-state differentiation compared to voltage-read schemes.For synaptic applications,SAW-driven weight updates in n-and p-type regimes produce anti-symmetric conductance trajectories,eliminating state collisions observed in electric-field-driven counterparts.This work pioneers acoustic wave manipulation of ambipolar transport,offering transformative strategies for degeneracy-free,high-precision neuromorphic electronics.展开更多
Anisotropic two-dimensional(2D)materials have garnered significant attention in recent years due to their polarization-sensitive photoresponse.However,the inherent crystal structure fundamentally limits the polarizati...Anisotropic two-dimensional(2D)materials have garnered significant attention in recent years due to their polarization-sensitive photoresponse.However,the inherent crystal structure fundamentally limits the polarization ratio of photocurrent to around 2,which is far below commercial requirements(>10).Here,the polarimetric photodetector based on vertical asymmetrical 1T’MoTe_(2)/MoS2/1T’MoTe_(2) dual van der Waals(vdWs)Schottky junction was demonstrated.Owing to the unique vertical dual-Schottky junction,the device exhibits excellent performance under 915 nm illumination,including a fast rise/decay time of 40/36μs,a broad 3 dB bandwidth of 12.5 kHz,and ultrahigh polarization ratios of 32(0.045 V)and 47(−0.015 V),potentially reaching infinity.Based on the outstanding response speed and polarization sensitivity,the device conveniently achieves polarization angle recognition for linear polarization light by switching external bias voltage without the aid of any polarizer or half-wave plate.In addition,the infrared angle of linear polarization(AoLP)imaging for a target obscured by a blocking film is demonstrated,in which targets with different polarization angles can be clearly distinguished.This work provides a novel scheme for next-generation integrated and all-in-one infrared polarimetric detection and imaging systems.展开更多
The realization of controllable polarity photoresponse within a single device is a crucial advancement for simulating biological bipolar vision cells to drive the development of next-generation optoelectronic technolo...The realization of controllable polarity photoresponse within a single device is a crucial advancement for simulating biological bipolar vision cells to drive the development of next-generation optoelectronic technologies.Nevertheless,current polarity photodetectors face significant challenges in fully suppressing symmetric photocurrent cancellation and optimizing carrier transport efficiency.Here,we propose a graphene-intercalated MoS_(2)/MoTe_(2)heterojunction,featuring a tailorable built-in electric field and a high efficiency transport channel.Spatially resolved photocurrent reveals that the controllable polarity photoresponse originates from the bias-dependent equivalent built-in electric field of MoS_(2)/MLG/MoTe_(2)heterojunction.The controllable polarity photoresponse realizes a large-area uniform“heart-shaped”photocurrent region.In enhanced polarity photoresponse mode,the photodetector exhibits broadband detection capabilities from visible(638 nm)to infrared(1550 nm)light,achieving a high responsivity of 18.1 A/W and an excellent detectivity of 2.8×10^(12)Jones,as well as fast response times of 94/119μs.Furthermore,precise imaging with a resolution better than 0.5 mm was successfully demonstrated,highlighting its polarity photoresponse for practical imaging applications.This work provides a new paradigm for controllable polarity photoresponse programmed by intercalated low-dimensional material structures,paving the way for next-generation intelligent sensing chips.展开更多
Phase transition and edge structure reconstruction of twodimensional(2D)materials are critical for modulating their properties and applications.Here,we employ a hydrogen-assisted annealing method to accomplish the ext...Phase transition and edge structure reconstruction of twodimensional(2D)materials are critical for modulating their properties and applications.Here,we employ a hydrogen-assisted annealing method to accomplish the extensive transformation from a 2H MoTe_(2)single crystal to Mo_(6)Te_(6)nanowires and quasi-2D Mo_(6)Te_(6)nanoribbons.Introducing hydrogen gas during atmospheric pressure annealing process generates a Te-poor chemical environment,which makes the transformations energetically favorable and is essential for the fast growth of Mo_(6)Te_(6)nanowires.Mo_(6)Te_(6)nanowires nucleate at the exposed edges of 2H MoTe_(2)and grow along its[1120],[2110],and[1210]crystallographic directions,demonstrating long-range order and forming quais-2D nanoribbons with lengths up to 50μm.Finally,nanoribbons align in sixfold oriented directions and form an array within 3 mm^(2)area on SiO_(2)/Si substrate.Mo_(6)Te_(6)nanowires display metallic behavior and have large charge transfer with Rhodamine 6G,making them excellent substrates for surface-enhanced Raman scattering.It shows a low detectable concentration of 10^(-13)mol/L for Rhodamine 6G and a Raman enhancement factor of 7×10^(8).Our findings provide an economic and efficient synthesis method for producing sixfold-oriented Mo_(6)Te_(6)nanowires and nanoribbons networks,which can serve as platform for exploring lowdimensional physical properties,designing electronic devices,and applications in analytical chemistry.展开更多
Two-dimensional(2D)transition metal dichalcogenides have been extensively studied due to their fascinating physical properties for constructing high-performance photodetectors.However,their relatively low responsiviti...Two-dimensional(2D)transition metal dichalcogenides have been extensively studied due to their fascinating physical properties for constructing high-performance photodetectors.However,their relatively low responsivities,current on/off ratios and response speeds have hindered their widespread application.Herein,we fabricated a high-performance photodetector based on few-layer MoTe_(2) and CdS_(0.42)Se_(0.58) flake heterojunctions.The photodetector exhibited a high responsivity of 7221 A/W,a large current on/off ratio of 1.73×10^(4),a fast response speed of 90/120μs,external quantum efficiency(EQE)reaching up to 1.52×10^(6)%and detectivity(D*)reaching up to 1.67×10^(15) Jones.The excellent performance of the heterojunction photodetector was analyzed by a photocurrent mapping test and first-principle calculations.Notably,the visible light imaging function was successfully attained on the MoTe_(2)/CdS_(0.42)Se_(0.58) photodetectors,indicating that the device had practical imaging application prospects.Our findings provide a reference for the design of ultrahighperformance MoTe_(2)-based photodetectors.展开更多
High-sensitivity room-temperature multi-dimensional infrared(IR)detection is crucial for military and civilian purposes.Recently,the gapless electronic structures and unique optoelectrical properties have made the two...High-sensitivity room-temperature multi-dimensional infrared(IR)detection is crucial for military and civilian purposes.Recently,the gapless electronic structures and unique optoelectrical properties have made the two-dimensional(2D)topological semimetals promising candidates for the realization of multifunctional optoelectronic devices.Here,we demonstrated the in-situ construction of high-performance 1T’-MoTe_(2)/Ge Schottky junction device by inserting an ultrathin AlOx passivation layer.The good detection performance with an ultra-broadband detection wavelength range of up to 10.6 micron,an ultrafast response time of~160 ns,and a large specific detectivity of over 109 Jones in mid-infrared(MIR)range surpasses that of most 2D materials-based IR sensors,approaching the performance of commercial IR photodiodes.The on-chip integrated device arrays with 64 functional detectors feature high-resolution imaging capability at room temperature.All these outstanding detection features have enabled the demonstration of position-sensitive detection applications.It demonstrates an exceptional position sensitivity of 14.9 mV/mm,an outstanding nonlinearity of 6.44%,and commendable trajectory tracking and optoelectronic demodulation capabilities.This study not only offers a promising route towards room-temperature MIR optoelectronic applications,but also demonstrates a great potential for application in optical sensing systems.展开更多
基金supported by the National Natural Science Foundation of China (21771137)。
文摘One-dimensional nanostructures(1D)with short ion diffusion distance and fast ion transport path are excellent for lithium-ion batteries(LIBs). However, the nature of layered transition metal dichalcogenides makes it difficult to form 1D nanohybrids. Here, the MoTe_(2) nanorods with an average diameter of 100-200 nm and length of 1-3 μm encapsulated by reduced graphene oxide(MoTe_(2)/rGO) have been fabricated via in-situ reaction of GO coated Mo_3O_(10)(C_(2)H_(10)N_(2)) nanowires with Te under Ar/H_(2) atmosphere. When applied as anode of LIBs, the Mo Te_(2)/r GO delivers a high reversible capacity(637 m A h g^(-1) after 100 cycles at 0.2 A g^(-1)), good rate capability(374 m A h g^(-1) at 2 A g^(-1)) and excellent stability(360 m A h g^(-1) after 200 cycles at 0.5 A g^(-1)), which surpasses bare Mo Te2 nanorods and bulk Mo Te2 crystallite. Furthermore, a lithium-ion full cell constructed by coupling Mo Te2/r GO anode and LiCoO_(2) cathode shows a capacity of 105 m A h g^(-1) at 0.1 C. The enhanced performance mainly benefits from the advantages of 1D nanostructure, and meanwhile the r GO thin layers are able to improve the conductivity and maintain the structural stability. This work provides a simple pathway for the synthesis of 1D TMDs nanostructures for energy storage and conversion.
基金the China Scholarship Council(Grant No.202107000030)RIE2020 Advanced Manufacturing and Engineering(AME)Programmatic(Grant No.A1898b0043)A*STAR Aerospace Programme(Grant No.M2115a0092)。
文摘The two-dimensional(2D)material-based thermal switch is attracting attention due to its novel applications,such as energy conversion and thermal management,in nanoscale devices.In this paper,we observed that the reversible 2H–1T′phase transition in MoTe_(2)is associated with about a fourfold/tenfold change in thermal conductivity along the X/Y direction by using first-principles calculations.This phenomenon can be profoundly understood by comparing the Mo–Te bonding strength between the two phases.The 2H-MoTe_(2)has one stronger bonding type,while 1T′-MoTe_(2)has three weaker types of bonds,suggesting bonding inhomogeneity in 1T′-MoTe_(2).Meanwhile,the bonding inhomogeneity can induce more scattering of vibration modes.The weaker bonding indicates a softer structure,resulting in lower phonon group velocity,a shorter phonon relaxation lifetime and larger Gr¨uneisen constants.The impact caused by the 2H to 1T′phase transition in MoTe_(2)hinders the propagation of phonons,thereby reducing thermal conductivity.Our study describes the possibility for the provision of the MoTe_(2)-based controllable and reversible thermal switch device.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51732010,51802341,and 12004415)the China Postdoctoral Science Foundation(Grant Nos.2020M671592,2019M661965)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20200255).
文摘Spin orbit torques(SOTs)in ferromagnet/heavy-metal heterostructures have provided great opportunities for efficient manipulation of spintronic devices.However,deterministically field-free switching of perpendicular magnetization with SOTs is forbidden because of the global two-fold rotational symmetry in conventional heavy-metal such as Pt.Here,we engineer the interface of Pt/Ni heterostructures by inserting a monolayer MoTe_(2)with low crystal symmetry.It is demonstrated that the spin orbit efficiency,as well as the out-of-plane magnetic anisotropy and the Gilbert damping of Ni are enhanced,due to the effect of orbital hybridization and the increased spin scatting at the interface induced by MoTe_(2).Particularly,an out-of-plane damping-like torque is observed when the current is applied perpendicular to the mirror plane of the MoTe_(2)crystal,which is attributed to the interfacial inversion symmetry breaking of the system.Our work provides an effective route for engineering the SOT in Pt-based heterostructures,and offers potential opportunities for van der Waals interfaces in spintronic devices.
文摘The direct synthesis of hydrogen peroxide(H_(2)O_(2))via a two‐electron oxygen reduction reaction(2e‐ORR)in acidic media has emerged as a green process for the production of this valuable chemical.However,such an approach employs expensive noble‐metal‐based electrocatalysts,which severely undermines its feasibility when implemented on an industrial scale.Herein,based on density functional theory computations and microkinetic modeling,we demonstrate that a novel two‐dimensional(2D)material,namely a 1T′‐MoTe_(2)monolayer,can serve as an efficient non‐precious electrocatalyst to facilitate the 2e‐ORR.The 1T′‐MoTe_(2)monolayer is a stable 2D crystal that can be easily produced through exfoliation techniques.The surface‐exposed Te sites of the 1T′‐MoTe_(2)monolayer exhibit a favorable OOH*binding energy of 4.24 eV,resulting in a rather high basal plane activity toward the 2e‐ORR.Importantly,kinetic computations indicate that the 1T'‐MoTe_(2)monolayer preferentially promotes the formation of H_(2)O_(2)over the competing four‐electron ORR step.These desirable characteristics render 1T′‐MoTe_(2)a promising candidate for catalyzing the electrochemical reduction of O_(2)to H_(2)O_(2).
基金The National Natural Science Foundation of China(No.12105190,62275174)the Shenzhen Key Laboratory of Applied Technologies of Super-Diamond and Functional Crystals(ZDSYS20230626091303007).
文摘Thin-film lithium niobate(TFLN)is considered a crucial platform in next-generation integrated optoelectronics due to its excellent optical properties.Photodetectors are essential components for constructing fully functional photonic circuits.However,due to the low electrical conductivity and weak light absorption,TFLN cannot be directly used for fabricating photodetectors.In this study,we proposed and demonstrated a high-performance MoTe_(2)/TFLN heterostructure integrated Schottky photodetector operating at telecommunication wavelengths(1310 nm and 1550 nm).This structure enhances the photovoltaic effect by bending MoTe_(2)at the edge of one electrode,thereby achieving self-powered operation.At a wavelength of 1310 nm,the photodetector achieves a self-powered responsivity of 70 mA/W,which is among the highest for waveguide-integrated photodetectors.Additionally,due to the strong rectification effect of the Schottky junction,the photodetector exhibits an extremely low dark current of only 25 pA at−0.5 V bias voltage.The on/off ratios reach 2.63104 at 0 V and 4.13104 at−0.5 V bias.The self-powered response times were measured,showing fast response and recovery times of 160μs and 169μs,respectively.
基金supported by the National Natural Science Foundation of China(Grant Nos.51991340,51991342,52225206,92163205,52188101,62322402,52350301,62204012,52250398,52303362,62304019)the National Key Research and Development Program of China(Grant No.2022YFA1203800,2022YFA1203803,2018YFA0703503,2023YFF1500400,2023YFF1500401)+7 种基金the Overseas Expertise Introduction Projects for Discipline Innovation(Grant No.B14003)the Frontier Cross Research Project of the Department of Chinese Academy of Sciences(Grant No.XK2023JSA001)the Beijing Nova Program(Grant No.20220484145,20230484478)the Young Elite Scientists sponsorship program by CAST(Grant No.2022QNRC001)the Fundamental Research Funds for the Central Universities(Grant No.FRF-06500207,FRF-TP-22-004C2,FRF-06500207,FRF-TP-22-004A1,FRF-IDRY-22-016)the State Key Lab for Advanced Metals andMaterials (No. 2023-Z05)Postdoctoral Fellowship Program of CPSF(GZC20230233)the Special support from the PostdoctoralScience Foundation (2023TQ0007).
文摘Two-dimensional(2D)MoTe_(2) shows great potential for future semiconductor devices,but the lab-to-fab transition is still in its preliminary stage due to the constraints in the crystal growth level.Currently,the chemical vapor deposition growth of 2D MoTe_(2) primarily relies on the tellurization process of Mo-source precursor(MSP).However,the target product 2H-MoTe_(2) from Mo precursor suffers from long growth time and suboptimal crystal quality,and MoO_(x) precursor confronts the dilemma of unclear growth mechanism and inconsistent growth products.Here,we developed magnetron-sputtered MoO_(3) film for fast and high-mobility 2H-MoTe_(2) growth.The solid-to-solid phase transition growth mechanism of 2D MoTe_(2) from Mo and MoO_(x) precursor was first experimentally unified,and the effect mechanism of MSPs on 2D MoTe_(2) growth was systematically elucidated.Compared with Mo and MoO2,the MoO_(3) precursor has the least Mo-unit lattice deformation and exhibits the optimal crystal quality of growth products.Meanwhile,the lowest Gibbs free energy change of the chemical reaction results in an impressive 2HMoTe_(2) growth rate of 8.07 mm/min.The constructed 2H-MoTe_(2) field-effect transistor array from MoO_(3) precursor showcases record-high hole mobility of 85 cm^(2)·V^(-1)·s^(-1),competitive on-off ratio of 3×10^(4),and outstanding uniformity.This scalable method not only offers efficiency but also aligns with industry standards,making it a promising guideline for diverse 2D material preparation towards real-world applications.
基金supported by the National Science Foundation of China(Nos.62431018 and 12034001)the National Key R&D Program(Nos.2024YFA1200125 and 2018YFA0307200).
文摘Two-dimensional(2D)materials hold immense potential for next-generation information devices due to their ambipolar transport and tunable electronic states.However,conventional electric-field-driven architectures suffer from inherent carrier-type degeneracy:Electrons and holes generate unidirectional currents,leading to ambiguous state overlaps in multi-level operation.Here,we demonstrate that surface acoustic waves(SAWs)break this symmetry in optically reconfigurable MoTe_(2)/h-BN heterostructures.SAWs induce type-II band modulation in the heterostructure and spatially separate electrons and holes into distinct valleys,enabling bidirectional acoustoelectric currents,whose polarity reverses with carrier type,controlled dynamically via ultraviolet(UV)illumination and gating.Leveraging this mechanism,we realize an 8-state memory device where SAW-driven readout currents changed between positive and negative polarities,achieving enhanced inter-state differentiation compared to voltage-read schemes.For synaptic applications,SAW-driven weight updates in n-and p-type regimes produce anti-symmetric conductance trajectories,eliminating state collisions observed in electric-field-driven counterparts.This work pioneers acoustic wave manipulation of ambipolar transport,offering transformative strategies for degeneracy-free,high-precision neuromorphic electronics.
基金the National Natural Science Foundation of China(No.52075207)the Fundamental Research Funds for the Central Universities(No.YCJJ20241102)the Shenzhen Science and Technology Program(No.JCYJ20240813153431041).
文摘Anisotropic two-dimensional(2D)materials have garnered significant attention in recent years due to their polarization-sensitive photoresponse.However,the inherent crystal structure fundamentally limits the polarization ratio of photocurrent to around 2,which is far below commercial requirements(>10).Here,the polarimetric photodetector based on vertical asymmetrical 1T’MoTe_(2)/MoS2/1T’MoTe_(2) dual van der Waals(vdWs)Schottky junction was demonstrated.Owing to the unique vertical dual-Schottky junction,the device exhibits excellent performance under 915 nm illumination,including a fast rise/decay time of 40/36μs,a broad 3 dB bandwidth of 12.5 kHz,and ultrahigh polarization ratios of 32(0.045 V)and 47(−0.015 V),potentially reaching infinity.Based on the outstanding response speed and polarization sensitivity,the device conveniently achieves polarization angle recognition for linear polarization light by switching external bias voltage without the aid of any polarizer or half-wave plate.In addition,the infrared angle of linear polarization(AoLP)imaging for a target obscured by a blocking film is demonstrated,in which targets with different polarization angles can be clearly distinguished.This work provides a novel scheme for next-generation integrated and all-in-one infrared polarimetric detection and imaging systems.
基金supported by National Key R&D Program of China(No.2023YFA1608701)the National Natural Science Foundation of China(Nos.62274168,11933006,U2141240,and 62005249)+3 种基金Hangzhou Leading Innovation and Entrepreneurship Team(No.TD2020002)Open Fund of State Key Laboratory of Infrared Physics(SITP-NLIST-YB-2023-13)Natural Science Foundation of Zhejiang Province(Nos.LZ24F050006 and LQ20F050005)the Research Funds of Hangzhou Institute for Advanced Study,UCAS(Nos.B02006C019025 and B02006C021010).
文摘The realization of controllable polarity photoresponse within a single device is a crucial advancement for simulating biological bipolar vision cells to drive the development of next-generation optoelectronic technologies.Nevertheless,current polarity photodetectors face significant challenges in fully suppressing symmetric photocurrent cancellation and optimizing carrier transport efficiency.Here,we propose a graphene-intercalated MoS_(2)/MoTe_(2)heterojunction,featuring a tailorable built-in electric field and a high efficiency transport channel.Spatially resolved photocurrent reveals that the controllable polarity photoresponse originates from the bias-dependent equivalent built-in electric field of MoS_(2)/MLG/MoTe_(2)heterojunction.The controllable polarity photoresponse realizes a large-area uniform“heart-shaped”photocurrent region.In enhanced polarity photoresponse mode,the photodetector exhibits broadband detection capabilities from visible(638 nm)to infrared(1550 nm)light,achieving a high responsivity of 18.1 A/W and an excellent detectivity of 2.8×10^(12)Jones,as well as fast response times of 94/119μs.Furthermore,precise imaging with a resolution better than 0.5 mm was successfully demonstrated,highlighting its polarity photoresponse for practical imaging applications.This work provides a new paradigm for controllable polarity photoresponse programmed by intercalated low-dimensional material structures,paving the way for next-generation intelligent sensing chips.
基金support from Research Groups of the National Natural Science Foundation of China(No.52121004)Hunan Key R&D Program Project(No.2022GK2005)+1 种基金the National Key R&D Program of the Ministry of Science and Technology of China(No.2022YFA1203801)the National Natural Science Foundation of China(Nos.51991340 and 51991343).
文摘Phase transition and edge structure reconstruction of twodimensional(2D)materials are critical for modulating their properties and applications.Here,we employ a hydrogen-assisted annealing method to accomplish the extensive transformation from a 2H MoTe_(2)single crystal to Mo_(6)Te_(6)nanowires and quasi-2D Mo_(6)Te_(6)nanoribbons.Introducing hydrogen gas during atmospheric pressure annealing process generates a Te-poor chemical environment,which makes the transformations energetically favorable and is essential for the fast growth of Mo_(6)Te_(6)nanowires.Mo_(6)Te_(6)nanowires nucleate at the exposed edges of 2H MoTe_(2)and grow along its[1120],[2110],and[1210]crystallographic directions,demonstrating long-range order and forming quais-2D nanoribbons with lengths up to 50μm.Finally,nanoribbons align in sixfold oriented directions and form an array within 3 mm^(2)area on SiO_(2)/Si substrate.Mo_(6)Te_(6)nanowires display metallic behavior and have large charge transfer with Rhodamine 6G,making them excellent substrates for surface-enhanced Raman scattering.It shows a low detectable concentration of 10^(-13)mol/L for Rhodamine 6G and a Raman enhancement factor of 7×10^(8).Our findings provide an economic and efficient synthesis method for producing sixfold-oriented Mo_(6)Te_(6)nanowires and nanoribbons networks,which can serve as platform for exploring lowdimensional physical properties,designing electronic devices,and applications in analytical chemistry.
基金This work was supported by the National Natural Science Foundation of China(Nos.11864046 and 11764046)the Basic Research Program of Yunnan Province(Nos.202001AT070064 and 202101AT070124)+1 种基金the Spring City Plan(Highlevel Talent Promotion and Training Project of Kunming)(No.2022SCP005)Yunnan Expert Workstation(No.202205AF150008).
文摘Two-dimensional(2D)transition metal dichalcogenides have been extensively studied due to their fascinating physical properties for constructing high-performance photodetectors.However,their relatively low responsivities,current on/off ratios and response speeds have hindered their widespread application.Herein,we fabricated a high-performance photodetector based on few-layer MoTe_(2) and CdS_(0.42)Se_(0.58) flake heterojunctions.The photodetector exhibited a high responsivity of 7221 A/W,a large current on/off ratio of 1.73×10^(4),a fast response speed of 90/120μs,external quantum efficiency(EQE)reaching up to 1.52×10^(6)%and detectivity(D*)reaching up to 1.67×10^(15) Jones.The excellent performance of the heterojunction photodetector was analyzed by a photocurrent mapping test and first-principle calculations.Notably,the visible light imaging function was successfully attained on the MoTe_(2)/CdS_(0.42)Se_(0.58) photodetectors,indicating that the device had practical imaging application prospects.Our findings provide a reference for the design of ultrahighperformance MoTe_(2)-based photodetectors.
基金the National Natural Science Foundation of China(Nos.U22A20138,62374149,and 62375279)the Collaborative Innovation Center of Suzhou Nano Science&Technology.The authors are grateful for the technical support from the Nano-X from Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(SINANO).
文摘High-sensitivity room-temperature multi-dimensional infrared(IR)detection is crucial for military and civilian purposes.Recently,the gapless electronic structures and unique optoelectrical properties have made the two-dimensional(2D)topological semimetals promising candidates for the realization of multifunctional optoelectronic devices.Here,we demonstrated the in-situ construction of high-performance 1T’-MoTe_(2)/Ge Schottky junction device by inserting an ultrathin AlOx passivation layer.The good detection performance with an ultra-broadband detection wavelength range of up to 10.6 micron,an ultrafast response time of~160 ns,and a large specific detectivity of over 109 Jones in mid-infrared(MIR)range surpasses that of most 2D materials-based IR sensors,approaching the performance of commercial IR photodiodes.The on-chip integrated device arrays with 64 functional detectors feature high-resolution imaging capability at room temperature.All these outstanding detection features have enabled the demonstration of position-sensitive detection applications.It demonstrates an exceptional position sensitivity of 14.9 mV/mm,an outstanding nonlinearity of 6.44%,and commendable trajectory tracking and optoelectronic demodulation capabilities.This study not only offers a promising route towards room-temperature MIR optoelectronic applications,but also demonstrates a great potential for application in optical sensing systems.
