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 development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising c...The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising candidates due to their built-in electric fields,ultrafast photocarrier separation,and tunable bandgaps,defect states limit their performance.Therefore,the modulation of the optoelectronic properties in such heterostructures is imperative.Surface charge transfer doping(SCTD)has emerged as a promising strategy for non-destructive modulation of electronic and optoelectronic characteristics in two-dimensional materials.In this work,we demonstrate the construction of high-performance p-i-n vertical heterojunction photodetectors through SCTD of MoTe_(2)/ReS_(2)heterostructure using p-type F_(4)-TCNQ.Systematic characterization reveals that the interfacial doping process effectively amplifies the built-in electric field,enhancing photogenerated carrier separation efficiency.Compared to the pristine heterojunction device,the doped photodetector exhibits remarkable visible to nearinfrared(635-1064 nm)performance.Particularly under 1064 nm illumination at zero bias,the device achieves a responsivity of 2.86 A/W and specific detectivity of 1.41×10^(12)Jones.Notably,the external quantum efficiency reaches an exceptional value of 334%compared to the initial 11.5%,while maintaining ultrafast response characteristics with rise/fall times of 11.6/15.6μs.This work provides new insights into interface engineering through molecular doping for developing high-performance vd W optoelectronic devices.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
油浸式变压器中的微量水分严重影响着变压器的油纸绝缘性能,实现变压器中微量水分的在线监测至关重要。文中以水分子(H_(2)O)在NiO掺杂MoTe_(2)单层上的吸附结构、吸附能(E_(a))、电荷转移量(ΔQ)、态密度(DOS)、最高占据及最低未占据...油浸式变压器中的微量水分严重影响着变压器的油纸绝缘性能,实现变压器中微量水分的在线监测至关重要。文中以水分子(H_(2)O)在NiO掺杂MoTe_(2)单层上的吸附结构、吸附能(E_(a))、电荷转移量(ΔQ)、态密度(DOS)、最高占据及最低未占据分子轨道(HOMO⁃LUMO)、功函数(WF)和差分电荷密度(DCD)为计算对象,基于泛函密度函数理论(density function theory,DFT)计算研究了过渡金属氧化物(NiO)掺杂对单层MoTe_(2)吸附参数和电子性质的影响。结果表明:与本征单层MoTe_(2)相比,过渡金属氧化物(NiO)掺杂单层MoTe_(2)的化学活性明显增强。此外,NiO掺杂的单层MoTe_(2)对H_(2)O分子均表现出优异的吸附及解吸附能力。因此,基于NiO掺杂的单层MoTe_(2)气敏材料可进一步用于在油浸式变压器微量水分的在线监测领域。展开更多
MoTe_(2) has emerged as a promising candidate in the field of integrated circuits,memristive devices,and catalysts,owing to its polymorphic nature across different phases.Experimentally,strain engineering has been dem...MoTe_(2) has emerged as a promising candidate in the field of integrated circuits,memristive devices,and catalysts,owing to its polymorphic nature across different phases.Experimentally,strain engineering has been demonstrated as an effective approach for manipulating the phase transition of MoTe_(2),but the mechanism remains unclear.The strain-dependent phase transition and its micro-mechanisms have been investigated based on first principle calculations.As demonstrated,critical strain and phase transition path from H→T'phases are strongly governed by the applied strain's orientation,magnitude,and triaxiality.At the atomic level,nonzero movements of Te atoms within the phase transition domain with mechanical unloading have been clarified,together with an advanced understanding on the impact of strain on Te-vacancies migration.These insights advanced the knowledge of MoTe_(2) phase transition behavior and demonstrated the large space to explore potential applications through strain,defect,and phase engineering.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
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financial support from 2024 Domestic Visiting Scholar Program for Teachers'Professional Development in Universities(Grant No.FX2024022)National Natural Science Foundation of China(Grant No.61904043)。
文摘The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising candidates due to their built-in electric fields,ultrafast photocarrier separation,and tunable bandgaps,defect states limit their performance.Therefore,the modulation of the optoelectronic properties in such heterostructures is imperative.Surface charge transfer doping(SCTD)has emerged as a promising strategy for non-destructive modulation of electronic and optoelectronic characteristics in two-dimensional materials.In this work,we demonstrate the construction of high-performance p-i-n vertical heterojunction photodetectors through SCTD of MoTe_(2)/ReS_(2)heterostructure using p-type F_(4)-TCNQ.Systematic characterization reveals that the interfacial doping process effectively amplifies the built-in electric field,enhancing photogenerated carrier separation efficiency.Compared to the pristine heterojunction device,the doped photodetector exhibits remarkable visible to nearinfrared(635-1064 nm)performance.Particularly under 1064 nm illumination at zero bias,the device achieves a responsivity of 2.86 A/W and specific detectivity of 1.41×10^(12)Jones.Notably,the external quantum efficiency reaches an exceptional value of 334%compared to the initial 11.5%,while maintaining ultrafast response characteristics with rise/fall times of 11.6/15.6μs.This work provides new insights into interface engineering through molecular doping for developing high-performance vd W optoelectronic devices.
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).
文摘油浸式变压器中的微量水分严重影响着变压器的油纸绝缘性能,实现变压器中微量水分的在线监测至关重要。文中以水分子(H_(2)O)在NiO掺杂MoTe_(2)单层上的吸附结构、吸附能(E_(a))、电荷转移量(ΔQ)、态密度(DOS)、最高占据及最低未占据分子轨道(HOMO⁃LUMO)、功函数(WF)和差分电荷密度(DCD)为计算对象,基于泛函密度函数理论(density function theory,DFT)计算研究了过渡金属氧化物(NiO)掺杂对单层MoTe_(2)吸附参数和电子性质的影响。结果表明:与本征单层MoTe_(2)相比,过渡金属氧化物(NiO)掺杂单层MoTe_(2)的化学活性明显增强。此外,NiO掺杂的单层MoTe_(2)对H_(2)O分子均表现出优异的吸附及解吸附能力。因此,基于NiO掺杂的单层MoTe_(2)气敏材料可进一步用于在油浸式变压器微量水分的在线监测领域。
基金supported by NSFC Grants(Nos.12032004,11872114,and 11502150)Natural Science Foundation of Hebei Province of China(No.A2016210060)+1 种基金The Higher Education Youth Talents Program of Hebei Province of China(No.BJ2017052)Science and Technology Project of Hebei Education Department(No.QN2020204)。
文摘MoTe_(2) has emerged as a promising candidate in the field of integrated circuits,memristive devices,and catalysts,owing to its polymorphic nature across different phases.Experimentally,strain engineering has been demonstrated as an effective approach for manipulating the phase transition of MoTe_(2),but the mechanism remains unclear.The strain-dependent phase transition and its micro-mechanisms have been investigated based on first principle calculations.As demonstrated,critical strain and phase transition path from H→T'phases are strongly governed by the applied strain's orientation,magnitude,and triaxiality.At the atomic level,nonzero movements of Te atoms within the phase transition domain with mechanical unloading have been clarified,together with an advanced understanding on the impact of strain on Te-vacancies migration.These insights advanced the knowledge of MoTe_(2) phase transition behavior and demonstrated the large space to explore potential applications through strain,defect,and phase engineering.
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.
