随着搭载于边缘终端上的图像与视频等数据密集型应用的日益增长,基于传统冯·诺依曼架构的互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)硬件系统正面临着能耗、速度和尺寸等多方面的挑战.神经形态器件包括...随着搭载于边缘终端上的图像与视频等数据密集型应用的日益增长,基于传统冯·诺依曼架构的互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)硬件系统正面临着能耗、速度和尺寸等多方面的挑战.神经形态器件包括具有存算一体特性的电学阻变器件和具有感存算一体特性的光电阻变器件,因其具有与生物神经系统的高相似度,及其高能效、高集成度、宽带宽等优势,在图像处理应用方面展现出巨大发展潜力.这类器件不仅能够用于加速传统图像低阶预处理和高阶处理中的大量运算,且能用于实现仿生物视觉系统的高效图像处理算法.本文介绍了最近的电学及光电神经形态阻变器件,并结合图像处理算法综述了神经形态阻变器件在图像处理方面的硬件实施和挑战,并对其发展前景提出了思考.展开更多
At least four two-or quasi-one-dimensional allotropes and a mixture of them were theoretically predicted or experimentally observed for low-dimensional Te,namely theα,β,γ,δ,and chiral-α+δphases.Among them theγ...At least four two-or quasi-one-dimensional allotropes and a mixture of them were theoretically predicted or experimentally observed for low-dimensional Te,namely theα,β,γ,δ,and chiral-α+δphases.Among them theγandαphases were found to be the most stable phases for monolayer and thicker layers,respectively.Here,we found two novel low-dimensional phases,namely theεandζphases.Theζphase is over 29 meV/Te more stable than the most stable monolayerγphase,and theεphase shows comparable stability with the most stable monolayerγphase.The energetic difference between theζandαphases reduces with respect to the increased layer thickness and vanishes at the four-layer(12-sublayer)thickness,while this thickness increases under change doping.Bothεandζphases are metallic chains and layers,respectively.Theζphase,with very strong interlayer coupling,shows quantum well states in its layer-dependent bandstructures.These results provide significantly insight into the understanding of polytypism in Te few-layers and may boost tremendous studies on properties of various few-layer phases.展开更多
Developing low-power FETs holds significant importance in advancing logic circuits,especially as the feature size of MOSFETs approaches sub-10 nanometers.However,this has been restricted by the thermionic limitation o...Developing low-power FETs holds significant importance in advancing logic circuits,especially as the feature size of MOSFETs approaches sub-10 nanometers.However,this has been restricted by the thermionic limitation of SS,which is limited to 60 mV per decade at room temperature.Herein,we proposed a strategy that utilizes 2D semiconductors with an isolated-band feature as channels to realize subthermionic SS in MOSFETs.Through high-throughput calculations,we established a guiding principle that combines the atomic structure and orbital interaction to identify their sub-thermionic transport potential.This guides us to screen 192 candidates from the 2D material database comprising 1608 systems.Additionally,the physical relationship between the sub-thermionic transport performances and electronic structures is further revealed,which enables us to predict 15 systems with promising device performances for low-power applications with supply voltage below 0.5 V.This work opens a new way for the low-power electronics based on 2D materials and would inspire extensive interests in the experimental exploration of intrinsic steep-slope MOSFETs.展开更多
Regulating chemical bonds to balance the adsorption and disassociation of water molecules on catalyst surfaces is crucial for overall water splitting in alkaline solution.Here we report a facile strategy for designing...Regulating chemical bonds to balance the adsorption and disassociation of water molecules on catalyst surfaces is crucial for overall water splitting in alkaline solution.Here we report a facile strategy for designing Ni2W4C-W3C Janus structures with abundant Ni-W metallic bonds on surfaces through interfacial engineering.Inserting Ni atoms into the W3C crystals in reaction progress generates a new Ni2 W4C phase,making the inert W atoms in W3C be active sites in Ni2W4C for overall water splitting.The Ni2W4CW3C/carbon nanofibers(Ni2 W4-W3C/CNFs)require overpotentials of 63 mV to reach 10 mA cm^-2 for hydrogen evolution reaction(HER)and 270 mV to reach 30 mA cm^-2 for oxygen evolution reaction(OER)in alkaline electrolyte,respectively.When utilized as both cathode and anode in alkaline solution for overall water splitting,cell voltages of 1.55 and 1.87 V are needed to reach 10 and 100 mA cm^-2,respectively.Density functional theory(DFT)results indicate that the strong interactions between Ni and W increase the local electronic states of W atoms.The Ni2W4C provides active sites for cleaving H-OH bonds,and the W3C facilitates the combination of Hads intermediates into H2 molecules.The in situ electrochemical-Raman results demonstrate that the strong absorption ability for hydroxyl and water molecules and further demonstrate that W atoms are the real active sites.展开更多
Recently,research on two-dimensional(2D)semiconductors has begun to translate from the fundamen-tal investigation into rudimentary functional circuits.In this work,we unveil the first functional MoS2 artificial neural...Recently,research on two-dimensional(2D)semiconductors has begun to translate from the fundamen-tal investigation into rudimentary functional circuits.In this work,we unveil the first functional MoS2 artificial neural network(ANN)chip,including multiply-and-accumulate(MAC),memory and activation function circuits.Such MoS2 ANN chip is realized through fabricating 818 field-effect transistors(FETs)on a wafer-scale and high-homogeneity MoS2 film,with a gate-last process to realize top gate structured FETs.A 62-level simulation program with integrated circuit emphasis(SPICE)model is utilized to design and optimize our analog ANN circuits.To demonstrate a practical application,a tactile digit sensing recognition was demonstrated based on our ANN circuits.After training,the digit recognition rate exceeds 97%.Our work not only demonstrates the protentional of 2D semiconductors in wafer-scale inte-grated circuits,but also paves the way for its future application in AI computation.展开更多
文摘随着搭载于边缘终端上的图像与视频等数据密集型应用的日益增长,基于传统冯·诺依曼架构的互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)硬件系统正面临着能耗、速度和尺寸等多方面的挑战.神经形态器件包括具有存算一体特性的电学阻变器件和具有感存算一体特性的光电阻变器件,因其具有与生物神经系统的高相似度,及其高能效、高集成度、宽带宽等优势,在图像处理应用方面展现出巨大发展潜力.这类器件不仅能够用于加速传统图像低阶预处理和高阶处理中的大量运算,且能用于实现仿生物视觉系统的高效图像处理算法.本文介绍了最近的电学及光电神经形态阻变器件,并结合图像处理算法综述了神经形态阻变器件在图像处理方面的硬件实施和挑战,并对其发展前景提出了思考.
基金Project supported by the Science Fund from the Ministry of Science and Technology(MOST)of China(Grant No.2018YFE0202700)the National Natural Science Foundation of China(Grant Nos.11274380,91433103,11622437,61674171,11974422,and 61761166009)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB30000000)the Fundamental Research Funds for the Central Universities of China and the Research Funds of Renmin University of China(Grant No.16XNLQ01)the Research Grant No.Council of Hong Kong,China(Grant No.N_PolyU540/17)the Hong Kong Polytechnic University(Grant No.G-SB53).Cong Wang was supported by the Outstanding Innovative Talents Cultivation Funded Programs 2017 of Renmin University of China.
文摘At least four two-or quasi-one-dimensional allotropes and a mixture of them were theoretically predicted or experimentally observed for low-dimensional Te,namely theα,β,γ,δ,and chiral-α+δphases.Among them theγandαphases were found to be the most stable phases for monolayer and thicker layers,respectively.Here,we found two novel low-dimensional phases,namely theεandζphases.Theζphase is over 29 meV/Te more stable than the most stable monolayerγphase,and theεphase shows comparable stability with the most stable monolayerγphase.The energetic difference between theζandαphases reduces with respect to the increased layer thickness and vanishes at the four-layer(12-sublayer)thickness,while this thickness increases under change doping.Bothεandζphases are metallic chains and layers,respectively.Theζphase,with very strong interlayer coupling,shows quantum well states in its layer-dependent bandstructures.These results provide significantly insight into the understanding of polytypism in Te few-layers and may boost tremendous studies on properties of various few-layer phases.
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_0428)the Training Program of the Major Research Plan of the National Natural Science Foundation of China(91964103)+3 种基金the Natural Science Foundation of Jiangsu Province(BK20180071)the Fundamental Research Funds for the Central Universities(30919011109)sponsored by Qing Lan Project of Jiangsu Province,and the Six Talent Peaks Project of Jiangsu Province(XCL-035)Research Grant Council of Hong Kong(CRS_PolyU502/22).
文摘Developing low-power FETs holds significant importance in advancing logic circuits,especially as the feature size of MOSFETs approaches sub-10 nanometers.However,this has been restricted by the thermionic limitation of SS,which is limited to 60 mV per decade at room temperature.Herein,we proposed a strategy that utilizes 2D semiconductors with an isolated-band feature as channels to realize subthermionic SS in MOSFETs.Through high-throughput calculations,we established a guiding principle that combines the atomic structure and orbital interaction to identify their sub-thermionic transport potential.This guides us to screen 192 candidates from the 2D material database comprising 1608 systems.Additionally,the physical relationship between the sub-thermionic transport performances and electronic structures is further revealed,which enables us to predict 15 systems with promising device performances for low-power applications with supply voltage below 0.5 V.This work opens a new way for the low-power electronics based on 2D materials and would inspire extensive interests in the experimental exploration of intrinsic steep-slope MOSFETs.
基金supported by the National Natural Science Foundation of China(51803077,51872204)the National Key Research and Development Program of China(2017YFA0204600)+4 种基金the Natural Science Foundation of Jiangsu Province(BK20180627)Postdoctoral Science Foundation of China(2018M630517,2019T120389)the Ministry of Education(MOE)and the State Administration for Foreign Expert Affairs(SAFEA),111 Project(B13025)the National First-Class Discipline Program of Light Industry Technology and Engineering(LITE2018-19)the Fundamental Research Funds for the Central Universities。
文摘Regulating chemical bonds to balance the adsorption and disassociation of water molecules on catalyst surfaces is crucial for overall water splitting in alkaline solution.Here we report a facile strategy for designing Ni2W4C-W3C Janus structures with abundant Ni-W metallic bonds on surfaces through interfacial engineering.Inserting Ni atoms into the W3C crystals in reaction progress generates a new Ni2 W4C phase,making the inert W atoms in W3C be active sites in Ni2W4C for overall water splitting.The Ni2W4CW3C/carbon nanofibers(Ni2 W4-W3C/CNFs)require overpotentials of 63 mV to reach 10 mA cm^-2 for hydrogen evolution reaction(HER)and 270 mV to reach 30 mA cm^-2 for oxygen evolution reaction(OER)in alkaline electrolyte,respectively.When utilized as both cathode and anode in alkaline solution for overall water splitting,cell voltages of 1.55 and 1.87 V are needed to reach 10 and 100 mA cm^-2,respectively.Density functional theory(DFT)results indicate that the strong interactions between Ni and W increase the local electronic states of W atoms.The Ni2W4C provides active sites for cleaving H-OH bonds,and the W3C facilitates the combination of Hads intermediates into H2 molecules.The in situ electrochemical-Raman results demonstrate that the strong absorption ability for hydroxyl and water molecules and further demonstrate that W atoms are the real active sites.
基金the National Key Research and Development Program of China(2016YFA0203900,2018YFB2202500)Innovation Program of Shanghai Municipal Education Commission(2021-01-07-00-07-E00077)+3 种基金Shanghai Municipal Science and Technology Commission(18JC1410300,21DZ1100900)Research Grant Council of Hong Kong(15205619)the National Natural Science Foundation of China(61925402,61934008,and 6210030233)the Natural Science Foundation of Shanghai(21ZR1405700)。
文摘Recently,research on two-dimensional(2D)semiconductors has begun to translate from the fundamen-tal investigation into rudimentary functional circuits.In this work,we unveil the first functional MoS2 artificial neural network(ANN)chip,including multiply-and-accumulate(MAC),memory and activation function circuits.Such MoS2 ANN chip is realized through fabricating 818 field-effect transistors(FETs)on a wafer-scale and high-homogeneity MoS2 film,with a gate-last process to realize top gate structured FETs.A 62-level simulation program with integrated circuit emphasis(SPICE)model is utilized to design and optimize our analog ANN circuits.To demonstrate a practical application,a tactile digit sensing recognition was demonstrated based on our ANN circuits.After training,the digit recognition rate exceeds 97%.Our work not only demonstrates the protentional of 2D semiconductors in wafer-scale inte-grated circuits,but also paves the way for its future application in AI computation.
