Hafnium-based ferroelectric films,remaining their ferroelectricity down to nanoscale thickness,present a promising application for low-power logic devices and nonvolatile memories.It has been appealing for researchers...Hafnium-based ferroelectric films,remaining their ferroelectricity down to nanoscale thickness,present a promising application for low-power logic devices and nonvolatile memories.It has been appealing for researchers to reduce the required temperature to obtain the ferroelectric phase in hafnium-based ferroelectric films for applications such as flexible and wearable electronics.This work demonstrates that a remanent polarization(P_(r))value of>5μC/cm^(2)can be obtained in asdeposited Hf_(0.5)Zr_(0.5)O_(2)(HZO)films that are fabricated by thermal atomic layer deposition(TALD)under low temperature of 250℃.The ferroelectric orthorhombic phase(o-phase)in the as-deposited HZO films is detected by scanning transmission electron microscopy(STEM).This low fabrication temperature further extends the compatibility of ferroelectric HZO films to flexible electronics and avoids the cost imposed by following high-temperature annealing treatments.展开更多
Owing to the outstanding properties provided by nontrivial band topology,topological phases of matter are considered as a promising platform towards low-dissipation electronics,efficient spin-charge conversion,and top...Owing to the outstanding properties provided by nontrivial band topology,topological phases of matter are considered as a promising platform towards low-dissipation electronics,efficient spin-charge conversion,and topological quantum computation.Achieving ferroelectricity in topological materials enables the non-volatile control of the quantum states,which could greatly facilitate topological electronic research.However,ferroelectricity is generally incompatible with systems featuring metallicity due to the screening effect of free carriers.In this study,we report the observation of memristive switching based on the ferroelectric surface state of a topological semimetal(TaSe_(4))2I.We find that the surface state of(TaSe_(4))2I presents out-of-plane ferroelectric polarization due to surface reconstruction.With the combination of ferroelectric surface and charge-density-wave-gapped bulk states,an electric-switchable barrier height can be achieved in(TaSe_(4))2I-metal contact.By employing a multi-terminal-grounding design,we manage to construct a prototype ferroelectric memristor based on(TaSe_(4))2I with on/off ratio up to 103,endurance over 103 cycles,and good retention characteristics.The origin of the ferroelectric surface state is further investigated by first-principles calculations,which reveal an interplay between ferroelectricity and band topology.The emergence of ferroelectricity in(TaSe_(4))2I not only demonstrates it as a rare but essential case of ferroelectric topological materials,but also opens new routes towards the implementation of topological materials in functional electronic devices.展开更多
Despite that in-sensor processing has been proposed to remove the latency and energy consumption during the inevitable data transfer between spatial-separated sensors,memories and processors in traditional computer vi...Despite that in-sensor processing has been proposed to remove the latency and energy consumption during the inevitable data transfer between spatial-separated sensors,memories and processors in traditional computer vision,its hardware implementation for artificial neural networks(ANNs)with all-in-one device arrays remains a challenge,especially for organic-based ANNs.With the advantages of biocompatibility,low cost,easy fabrication and flexibility,here we implement a self-powered in-sensor ANN using molecular ferroelectric(MF)-based photomemristor arrays.Tunable ferroelectric depolarization was intentionally introduced into the ANN,which enables reconfigurable conductance and photoresponse.Treating photoresponsivity as synaptic weight,the MFbased in-sensor ANN can operate analog convolutional computation,and successfully conduct perception and recognition of white-light letter images in experiments,with low processing energy consumption.Handwritten Chinese digits are also recognized and regressed by a large-scale array,demonstrating its scalability and potential for low-power processing and the applications in MF-based in-situ artificial retina.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2021YFA1200700)the National Natural Science Foundation of China(Grant Nos.T2222025 and 62174053)+5 种基金the Open Research Projects of Zhejiang Laboratory(Grant No.2021MD0AB03)the Shanghai Science and Technology Innovation Action Plan(Grant Nos.21JC1402000 and 21520714100)the Guangdong Provincial Key Laboratory Program(Grant No.2021B1212040001)the Fundamental Research Funds for the Central Universitiessupport from the Zuckerman STEM Leadership ProgramPazy Research Foundation(Grant No.149-2020)。
文摘Hafnium-based ferroelectric films,remaining their ferroelectricity down to nanoscale thickness,present a promising application for low-power logic devices and nonvolatile memories.It has been appealing for researchers to reduce the required temperature to obtain the ferroelectric phase in hafnium-based ferroelectric films for applications such as flexible and wearable electronics.This work demonstrates that a remanent polarization(P_(r))value of>5μC/cm^(2)can be obtained in asdeposited Hf_(0.5)Zr_(0.5)O_(2)(HZO)films that are fabricated by thermal atomic layer deposition(TALD)under low temperature of 250℃.The ferroelectric orthorhombic phase(o-phase)in the as-deposited HZO films is detected by scanning transmission electron microscopy(STEM).This low fabrication temperature further extends the compatibility of ferroelectric HZO films to flexible electronics and avoids the cost imposed by following high-temperature annealing treatments.
基金supported by the National Key R&D Program of China(2022YFA1405700)the National Natural Science Foundation of China(12174069 and 92365104)+8 种基金Shuguang Program from the Shanghai Education Development Foundationsupported by the National Key R&D Program of China(2023YFA1407500)the National Natural Science Foundation of China(12174104 and 62005079)supported by the National Key R&D Program of China(2022YFA1402901)National Natural Science Foundation of China(12274082)Shanghai Science and Technology Committee(23ZR1406600)Shanghai Pilot Program for Basic Research-FuDan University 21TQ1400100(23TQ017)supported by the China Postdoctoral Science Foundation(2022M720816)supported by the National Key R&D Program of China(2022YFA1402902)。
文摘Owing to the outstanding properties provided by nontrivial band topology,topological phases of matter are considered as a promising platform towards low-dissipation electronics,efficient spin-charge conversion,and topological quantum computation.Achieving ferroelectricity in topological materials enables the non-volatile control of the quantum states,which could greatly facilitate topological electronic research.However,ferroelectricity is generally incompatible with systems featuring metallicity due to the screening effect of free carriers.In this study,we report the observation of memristive switching based on the ferroelectric surface state of a topological semimetal(TaSe_(4))2I.We find that the surface state of(TaSe_(4))2I presents out-of-plane ferroelectric polarization due to surface reconstruction.With the combination of ferroelectric surface and charge-density-wave-gapped bulk states,an electric-switchable barrier height can be achieved in(TaSe_(4))2I-metal contact.By employing a multi-terminal-grounding design,we manage to construct a prototype ferroelectric memristor based on(TaSe_(4))2I with on/off ratio up to 103,endurance over 103 cycles,and good retention characteristics.The origin of the ferroelectric surface state is further investigated by first-principles calculations,which reveal an interplay between ferroelectricity and band topology.The emergence of ferroelectricity in(TaSe_(4))2I not only demonstrates it as a rare but essential case of ferroelectric topological materials,but also opens new routes towards the implementation of topological materials in functional electronic devices.
基金supported by National Key Research and Development Program of China(2021YFA1200700)The National Natural Science Foundation of China(No.52372120,T2222025 and 62174053)+1 种基金Shanghai Science and Technology Innovation Action Plan(21JC1402000 and 21520714100)the Fundamental Research Funds for the Central Universities。
基金supported by the National Key Research and Development Program of China for International Cooperation(2020YFE0191300)the National Natural Science Foundation of China(Nos.62074040,61804055,T2222025 and 62174053)+1 种基金the Natural Science Foundation of Shanghai(No.20ZR1404000)Open Research Projects of Zhejiang Lab(2021MD0AB03).
文摘Despite that in-sensor processing has been proposed to remove the latency and energy consumption during the inevitable data transfer between spatial-separated sensors,memories and processors in traditional computer vision,its hardware implementation for artificial neural networks(ANNs)with all-in-one device arrays remains a challenge,especially for organic-based ANNs.With the advantages of biocompatibility,low cost,easy fabrication and flexibility,here we implement a self-powered in-sensor ANN using molecular ferroelectric(MF)-based photomemristor arrays.Tunable ferroelectric depolarization was intentionally introduced into the ANN,which enables reconfigurable conductance and photoresponse.Treating photoresponsivity as synaptic weight,the MFbased in-sensor ANN can operate analog convolutional computation,and successfully conduct perception and recognition of white-light letter images in experiments,with low processing energy consumption.Handwritten Chinese digits are also recognized and regressed by a large-scale array,demonstrating its scalability and potential for low-power processing and the applications in MF-based in-situ artificial retina.
