Emulation of advanced synaptic functions of the human brain with electronic devices contributes an important step toward constructing high‐efficiency neuromorphic systems.Ferroelectric materials are promising candida...Emulation of advanced synaptic functions of the human brain with electronic devices contributes an important step toward constructing high‐efficiency neuromorphic systems.Ferroelectric materials are promising candidates as synaptic weight elements in neural network hardware due to their controllable polarization states.However,the increased depolarization field at the na-noscale and the complex fabrication process of the traditional ferroelectric materials hamper the development of high‐density,low‐power,and highly sensitive synaptic devices.Here,we report the implementation of two‐dimensional(2D)ferroelectricα‐In_(2)Se_(3)as an active channel material to emulate typical synaptic functions.Theα‐In_(2)Se_(3)‐based synaptic device fea-tures multimode operations,enabled by the coupled ferroelectric polarization under various voltage pulses applied at both drain and gate terminals.Moreover,the energy consumption can be reduced to~1 pJ by using high‐κdielectric(Al2O3).The successful control of ferroelectric polarizations inα‐In_(2)Se_(3)and its application in artificial synapses are expected to inspire the implementation of 2D ferroelectric materials for future neuromorphic systems.展开更多
Ferroelectric materials hold great potential for modulating two-dimensional(2D)materials to achieve electrically tunable homojunction(ETH).However,ETH based on conventional ferroelectrics encounters significant challe...Ferroelectric materials hold great potential for modulating two-dimensional(2D)materials to achieve electrically tunable homojunction(ETH).However,ETH based on conventional ferroelectrics encounters significant challenges attributed to the surface with dangling bonds and the associated depolarization field.Here,we introduce a novel 2D ETH device based on the anomalous interfacial effect between 2D layered ferroelectric CuCrP_(2)S_(6) and ambipolar WSe_(2),creating a versatile platform for nonvolatile memory and high-performance optoelectronic applications.The device capitalizes on the realization of ETH through a localized doping strategy facilitated by ferroelectric polarizationassisted charge trapping.When modulated to a p–n junction diode,the device showcases superior rectifying characteristics and high-performance selfpowered photodetection,with a highest responsivity over 0.14 A·W^(-1).Moreover,the nonvolatile ETH device enables a single device to implement complex optoelectronic logics of exclusive OR(XOR),OR,and not implication(NIMP)that can be reconfigured by light illumination.Compared to the traditional CMOS-based logics,the ETH device significantly reduces the transistor number by 87.5%,83.3%,and 87.5%for XOR,OR,and NIMP,respectively.The successful demonstration of the ETH device based on 2D ferroelectric materials paves the way for the development of advanced and simplified photo-electric interconnected circuits.展开更多
The artificial intelligence era has witnessed a surge of demand in detection and recognition of biometric information,with applications from financial services to information security.However,the physical separation o...The artificial intelligence era has witnessed a surge of demand in detection and recognition of biometric information,with applications from financial services to information security.However,the physical separation of sensing,memory,and computational units in traditional biometric systems introduces severe decision latency and operational power consumption.Herein,an in-sensor reservoir computing(RC)system based on MoTe_(2)/BaTiO_(3)optical synapses is proposed to detect and recognize the faces and fingerprints information.In optical operation mode,the device exhibits low energy consumption of 41.2 pJ,long retention time of 3×10^(4)s,high endurance of 10^(4)switching cycles,and multifunctional sensing-memory-computing visual simulations.The light intensity-dependent optical sensing and multilevel optical storage properties are exploited to achieve sunburned eye simulation and image memory functions.These nonlinear,multi-state,short-term storage,and long-term memory characteristics make MoTe_(2)/BaTiO_(3)optical synapses a suitable reservoir layer and readout layer,with short-term properties to project complicated input features into high-dimensional output features,and long-term properties to be used as a readout layer,thus further building an in-sensor RC system for face and fingerprint recognition.Under the 40%Gaussian noise environment,the system achieves 91.73%recognition accuracy for face and 97.50%for fingerprint images,and experimental verification is carried out,which shows potential in practical applications.These results provide a strategy for constructing a high-performance in-sensor RC system for high-accuracy biometric identification.展开更多
Ferroelectric memory is a promising candidate for next-generation nonvolatile memory owing to its outstanding performance such as low power consump-tion,fast speed,and high endurance.However,the ferroelectricity of co...Ferroelectric memory is a promising candidate for next-generation nonvolatile memory owing to its outstanding performance such as low power consump-tion,fast speed,and high endurance.However,the ferroelectricity of conven-tional ferroelectric materials will be eliminated by the depolarization field when the size drops to the nanometer scale.As a result,the miniaturization of ferroelectric devices was hindered,which makes ferroelectric memory unable to keep up with the development of integrated-circuit(IC)miniaturization.Recently,a two-dimensional(2D)In2Se3 was reported to maintain stable ferro-electricity at the ultrathin scale,which is expected to break through the bottle-neck of miniaturization.Soon,devices based on 2D In2Se3,including the ferroelectric field-effect transistor,ferroelectric channel transistor,synaptic fer-roelectric semiconductor junction,and ferroelectric memristor were demon-strated.However,a comprehensive understanding of the structures and the ferroelectric-switching mechanism of 2D In2Se3 is still lacking.Here,the atomic structures of different phases,the dynamic mechanism of ferroelectric switching,and the performance/functions of the latest devices of 2D In2Se3 are reviewed.Furthermore,the correlations among the structures,the properties,and the device performance are analyzed.Finally,several crucial problems or challenges and possible research directions are put forward.We hope that this review paper can provide timely knowledge and help for the research commu-nity to develop 2D In2Se3 based ferroelectric memory and computing technol-ogy for practical industrial applications.展开更多
Ferroelectricity and metallicity are usually believed not to coexist because conducting electrons would screen out static internal electric fields.In 1965,Anderson and Blount proposed the concept of"ferroelectric...Ferroelectricity and metallicity are usually believed not to coexist because conducting electrons would screen out static internal electric fields.In 1965,Anderson and Blount proposed the concept of"ferroelectric metal",however,it is only until recently that very rare ferroelectric metals were reported.Here,by combining high-throughput ab initio calculations and data-driven machine learning method with new electronic orbital based descriptors,we systematically investigated a large family(2964)of two-dimensional(2D)bimetal phosphates,and discovered 60 stable ferroelectrics with out-of-plane polarization,including 16 ferroelectric metals and 44 ferroelectric semiconductors that contain seven multiferroics.The ferroelectricity origins from spontaneous symmetry breaking induced by the opposite displacements of bimetal atoms,and the full-d-orbital coinage metal elements cause larger displacements and polarization than other elements.For 2D ferroelectric metals,the odd electrons per unit cell without spin polarization may lead to a half-filled energy band around Fermi level and is responsible for the metallicity.It is revealed that the conducting electrons mainly move on a single-side surface of the 2D layer,while both the ionic and electric contributions to polarization come from the other side and are vertical to the above layer,thereby causing the coexistence of metallicity and ferroelectricity.Van der Waals heterostructures based on ferroelectric metals may enable the change of Schottky barrier height or the Schottky-Ohmic contact type and induce a dramatic change of their vertical transport properties.Our work greatly expands the family of 2D ferroelectric metals and will spur further exploration of 2D ferroelectric metals.展开更多
Combining logical function and memory characteristics of transistors is an ideal strategy for enhancing computational efficiency of transistor devices.Here,we rationally design a tri-gate two-dimensional(2D)ferroelect...Combining logical function and memory characteristics of transistors is an ideal strategy for enhancing computational efficiency of transistor devices.Here,we rationally design a tri-gate two-dimensional(2D)ferroelectric van der Waals heterostructures device based on copper indium thiophosphate(CuInP_(2)S_(6))and few layers tungsten disulfide(WS_(2)),and demonstrate its multi-functional applications in multi-valued state of data,non-volatile storage,and logic operation.By co-regulating the input signals across the tri-gate,we show that the device can switch functions flexibly at a low supply voltage of 6 V,giving rise to an ultra-high current switching ratio of 107 and a low subthreshold swing of 53.9 mV/dec.These findings offer perspectives in designing smart 2D devices with excellent functions based on ferroelectric van der Waals heterostructures.展开更多
基金Ministry of Education—Singapore,Grant/Award Number:MOE‐2019‐T2‐1‐002National Natural Science Foundation of China,Grant/Award Numbers:21872100,U2032147Agency for Science,Technology and Research,Grant/Award Numbers:A1938c0035,A20G9b0135。
文摘Emulation of advanced synaptic functions of the human brain with electronic devices contributes an important step toward constructing high‐efficiency neuromorphic systems.Ferroelectric materials are promising candidates as synaptic weight elements in neural network hardware due to their controllable polarization states.However,the increased depolarization field at the na-noscale and the complex fabrication process of the traditional ferroelectric materials hamper the development of high‐density,low‐power,and highly sensitive synaptic devices.Here,we report the implementation of two‐dimensional(2D)ferroelectricα‐In_(2)Se_(3)as an active channel material to emulate typical synaptic functions.Theα‐In_(2)Se_(3)‐based synaptic device fea-tures multimode operations,enabled by the coupled ferroelectric polarization under various voltage pulses applied at both drain and gate terminals.Moreover,the energy consumption can be reduced to~1 pJ by using high‐κdielectric(Al2O3).The successful control of ferroelectric polarizations inα‐In_(2)Se_(3)and its application in artificial synapses are expected to inspire the implementation of 2D ferroelectric materials for future neuromorphic systems.
基金Natural Science Foundation of China,Grant/Award Number:62274118Singapore National Research Foundation Investigatorship Program,Grant/Award Number:NRF NRFI08-2022-0009+2 种基金SUSTech-NUS Joint Research ProgramScience and Engineering Research Council of A*STAR(Agency for Science,Technology and Research)Singapore,Grant/Award Number:A20G9b0135Science and Technology Commission of Shanghai Municipality,the Shanghai Venus Sailing Program,Grant/Award Number:24YF2712800。
文摘Ferroelectric materials hold great potential for modulating two-dimensional(2D)materials to achieve electrically tunable homojunction(ETH).However,ETH based on conventional ferroelectrics encounters significant challenges attributed to the surface with dangling bonds and the associated depolarization field.Here,we introduce a novel 2D ETH device based on the anomalous interfacial effect between 2D layered ferroelectric CuCrP_(2)S_(6) and ambipolar WSe_(2),creating a versatile platform for nonvolatile memory and high-performance optoelectronic applications.The device capitalizes on the realization of ETH through a localized doping strategy facilitated by ferroelectric polarizationassisted charge trapping.When modulated to a p–n junction diode,the device showcases superior rectifying characteristics and high-performance selfpowered photodetection,with a highest responsivity over 0.14 A·W^(-1).Moreover,the nonvolatile ETH device enables a single device to implement complex optoelectronic logics of exclusive OR(XOR),OR,and not implication(NIMP)that can be reconfigured by light illumination.Compared to the traditional CMOS-based logics,the ETH device significantly reduces the transistor number by 87.5%,83.3%,and 87.5%for XOR,OR,and NIMP,respectively.The successful demonstration of the ETH device based on 2D ferroelectric materials paves the way for the development of advanced and simplified photo-electric interconnected circuits.
基金supported by the National Key R&D Plan“Nano Frontier”Key Special Project(Grant No.2021YFA1200502)Cultivation Projects of National Major R&D Project(Grant No.92164109)+13 种基金the National Natural Science Foundation of China(Grant Nos.61874158,62004056,and 62104058)the Special Project of Strategic Leading Science and Technology of Chinese Academy of Sciences(Grant No.XDB44000000-7)Key R&D Plan Projects in Hebei Province(Grant No.22311101D)Hebei Basic Research Special Key Project(Grant No.F2021201045)the Support Program for the Top Young Talents of Hebei Province(Grant No.70280011807)the Supporting Plan for 100 Excellent Innovative Talents in Colleges and Universities of Hebei Province(Grant No.SLRC2019018)the Interdisciplinary Research Program of Natural Science of Hebei University(No.DXK202101)the Institute of Life Sciences and Green Development(No.521100311)the Natural Science Foundation of Hebei Province(Nos.F2022201054 and F2021201022)the Outstanding Young Scientific Research and Innovation Team of Hebei University(Grant No.605020521001)the Special Support Funds for National High Level Talents(Grant No.041500120001)the Advanced Talents Incubation Program of the Hebei University(Grant Nos.521000981426,521100221071,and 521000981363)the Science and Technology Project of Hebei Education Department(Grant Nos.QN2020178 and QN2021026)Postgraduate's Innovation Fund Project of Hebei Province(CXZZBS2024004).
文摘The artificial intelligence era has witnessed a surge of demand in detection and recognition of biometric information,with applications from financial services to information security.However,the physical separation of sensing,memory,and computational units in traditional biometric systems introduces severe decision latency and operational power consumption.Herein,an in-sensor reservoir computing(RC)system based on MoTe_(2)/BaTiO_(3)optical synapses is proposed to detect and recognize the faces and fingerprints information.In optical operation mode,the device exhibits low energy consumption of 41.2 pJ,long retention time of 3×10^(4)s,high endurance of 10^(4)switching cycles,and multifunctional sensing-memory-computing visual simulations.The light intensity-dependent optical sensing and multilevel optical storage properties are exploited to achieve sunburned eye simulation and image memory functions.These nonlinear,multi-state,short-term storage,and long-term memory characteristics make MoTe_(2)/BaTiO_(3)optical synapses a suitable reservoir layer and readout layer,with short-term properties to project complicated input features into high-dimensional output features,and long-term properties to be used as a readout layer,thus further building an in-sensor RC system for face and fingerprint recognition.Under the 40%Gaussian noise environment,the system achieves 91.73%recognition accuracy for face and 97.50%for fingerprint images,and experimental verification is carried out,which shows potential in practical applications.These results provide a strategy for constructing a high-performance in-sensor RC system for high-accuracy biometric identification.
基金China Postdoctoral Science Foundation,Grant/Award Number:2019M661200National Natural Science Foundation of China,Grant/Award Numbers:11874171,11904118,61922035Fundamental Research Funds for the Central Universities。
文摘Ferroelectric memory is a promising candidate for next-generation nonvolatile memory owing to its outstanding performance such as low power consump-tion,fast speed,and high endurance.However,the ferroelectricity of conven-tional ferroelectric materials will be eliminated by the depolarization field when the size drops to the nanometer scale.As a result,the miniaturization of ferroelectric devices was hindered,which makes ferroelectric memory unable to keep up with the development of integrated-circuit(IC)miniaturization.Recently,a two-dimensional(2D)In2Se3 was reported to maintain stable ferro-electricity at the ultrathin scale,which is expected to break through the bottle-neck of miniaturization.Soon,devices based on 2D In2Se3,including the ferroelectric field-effect transistor,ferroelectric channel transistor,synaptic fer-roelectric semiconductor junction,and ferroelectric memristor were demon-strated.However,a comprehensive understanding of the structures and the ferroelectric-switching mechanism of 2D In2Se3 is still lacking.Here,the atomic structures of different phases,the dynamic mechanism of ferroelectric switching,and the performance/functions of the latest devices of 2D In2Se3 are reviewed.Furthermore,the correlations among the structures,the properties,and the device performance are analyzed.Finally,several crucial problems or challenges and possible research directions are put forward.We hope that this review paper can provide timely knowledge and help for the research commu-nity to develop 2D In2Se3 based ferroelectric memory and computing technol-ogy for practical industrial applications.
基金the National Key R&D Program of China(2018YFA0305800)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB28000000)+2 种基金the National Natural Science Foundation of China(11834014)Beijing Municipal Science and Technology Commission(Z191100007219013)University of Chinese Academy of Sciences。
文摘Ferroelectricity and metallicity are usually believed not to coexist because conducting electrons would screen out static internal electric fields.In 1965,Anderson and Blount proposed the concept of"ferroelectric metal",however,it is only until recently that very rare ferroelectric metals were reported.Here,by combining high-throughput ab initio calculations and data-driven machine learning method with new electronic orbital based descriptors,we systematically investigated a large family(2964)of two-dimensional(2D)bimetal phosphates,and discovered 60 stable ferroelectrics with out-of-plane polarization,including 16 ferroelectric metals and 44 ferroelectric semiconductors that contain seven multiferroics.The ferroelectricity origins from spontaneous symmetry breaking induced by the opposite displacements of bimetal atoms,and the full-d-orbital coinage metal elements cause larger displacements and polarization than other elements.For 2D ferroelectric metals,the odd electrons per unit cell without spin polarization may lead to a half-filled energy band around Fermi level and is responsible for the metallicity.It is revealed that the conducting electrons mainly move on a single-side surface of the 2D layer,while both the ionic and electric contributions to polarization come from the other side and are vertical to the above layer,thereby causing the coexistence of metallicity and ferroelectricity.Van der Waals heterostructures based on ferroelectric metals may enable the change of Schottky barrier height or the Schottky-Ohmic contact type and induce a dramatic change of their vertical transport properties.Our work greatly expands the family of 2D ferroelectric metals and will spur further exploration of 2D ferroelectric metals.
基金supported by the National Natural Science Foundation of China(No.62104073)the China Postdoctoral Science Foundation(No.2021M691088)+1 种基金the Pearl River Talent Recruitment Program(No.2019ZT08X639)Z.C.W.acknowledges the European Research Executive Agency(Project 101079184-FUNLAYERS).
文摘Combining logical function and memory characteristics of transistors is an ideal strategy for enhancing computational efficiency of transistor devices.Here,we rationally design a tri-gate two-dimensional(2D)ferroelectric van der Waals heterostructures device based on copper indium thiophosphate(CuInP_(2)S_(6))and few layers tungsten disulfide(WS_(2)),and demonstrate its multi-functional applications in multi-valued state of data,non-volatile storage,and logic operation.By co-regulating the input signals across the tri-gate,we show that the device can switch functions flexibly at a low supply voltage of 6 V,giving rise to an ultra-high current switching ratio of 107 and a low subthreshold swing of 53.9 mV/dec.These findings offer perspectives in designing smart 2D devices with excellent functions based on ferroelectric van der Waals heterostructures.
