Photodetectors and optoelectronic synapses are vital for construction of artificial visual perception system.However,the hardware implementations of optoelectronic-neuromorphic devices based on conventional architectu...Photodetectors and optoelectronic synapses are vital for construction of artificial visual perception system.However,the hardware implementations of optoelectronic-neuromorphic devices based on conventional architecture usually suffer from poor scalability,light response range,and limited functionalities.Here,large-scale flexible monolayer MoS_(2)devices integrating photodetectors and optoelectronic synapses over the entire visible spectrum in one device have been realized,which can be used in photodetection,optical communication,artificial visual perception system,and optical artificial neural network.By modulating gate voltages,we enable MoS_(2)-based devices to be photodetectors and also optoelectronic synapses.Importantly,the MoS_(2)-based optoelectronic synapses could implement many synaptic functions and neuromorphic characteristics,such as short-term memory(STM),long-term memory(LTM),paired-pulse facilitation(PPF),long-term potentiation(LTP)/long-term depression(LTD),and“learning-experience”behavior.Furthermore,an associative learning behavior(the classical conditioning Pavlov’s dog experiment)was emulated using paired stimulation of optical and voltage pulses.These results facilitate the development of MoS_(2)-based multifunctional optoelectronic devices with a simple device structure,showing great potential for photodetection,optoelectronic neuromorphic computing,human visual systems mimicking,as well as wearable and implantable electronics.展开更多
Metal-semiconductor diodes constructed from two-dimensional(2D)van der Waals heterostructures show excellent gate electrostatics and a large built-in electric field at the tunnel junction,which can be exploited to mak...Metal-semiconductor diodes constructed from two-dimensional(2D)van der Waals heterostructures show excellent gate electrostatics and a large built-in electric field at the tunnel junction,which can be exploited to make highly sensitive photodetector.Here we demonstrate a metal-semiconductor photodiode constructed by the monolayer graphene(Gr)on a few-layer black phosphorus(BP).Due to the presence of a built-in potential barrier(~0.09±0.03 eV)at the Gr-BP interface,the photoresponsivity of the Gr-BP device is enhanced by a factor of 672%,and the external quantum efficiency(EQE)increases to648%from 84%of the bare BP.Electrostatic gating allows the BP channel to be switched between p-type and n-type conduction.We further demonstrate that excitation laser power can be used to control the current polarity of the Gr-BP device due to photon-induced doping.The versatility of the Gr-BP junctions in terms of electrostatic bias-induced or light-induced switching of current polarity is potentially useful for making dynamically reconfigurable digital circuits.展开更多
The ability to control transport behaviors in nanostructure is crucial for usage as a fundamental research platform as well as a practical device.In this study,we report a gate-controlled crossover of electron transpo...The ability to control transport behaviors in nanostructure is crucial for usage as a fundamental research platform as well as a practical device.In this study,we report a gate-controlled crossover of electron transport behaviors using graphene nanoconstrictions as a platform.The observed transport properties span from Coulomb blockade-dominated single electron transmission to electron-wave interference-dominated quantum behavior.Such drastic modulation is achieved by utilizing a single back gate on a graphene nanoconstriction structure,where the size of nanostructure in the constriction and coupling strength of it to the electrodes can be tuned electrically.Our results indicate that electrostatic field by gate voltage upon the confined nanostructure defines both the size of the nanoconstriction as well as its interaction to electrodes.Increasing gate voltage raises Fermi level to cross the energy profile in the nanoconstriction,resulting in decreased energy barriers which affect the size of nanoconstriction and transmissivity of electrons.The gate-tunable nanoconstriction device can therefore become a potential platform to study quantum critical behaviors and enrich electronic and spintronic devices.展开更多
The heterojunction integration of two-dimensional(2D)materials via van der Waals(vdW)forces,unencumbered by lattice and processing constraints,constitutes an efficacious approach to enhance the overall optoelectronic ...The heterojunction integration of two-dimensional(2D)materials via van der Waals(vdW)forces,unencumbered by lattice and processing constraints,constitutes an efficacious approach to enhance the overall optoelectronic performance of photodetectors,due to an assortment of distinctive light-matter interactions.Nonetheless,vdW heterojunction photodetectors based on transition metal dichalcogenides(TMDs)face an inevitable trade-off between low dark currents and high responsivity,curtailing the application potential of myriad novel optoelectronic components in sensing,spectral,and communication systems.In this study,we present the successful actualization of a highly sensitive,self-powered,and gate-tunable bipolar response photodetector.The mechanisms underlying photocurrent generation were scrutinized via bias-,power-,and position-dependent mapping photoresponse measurements,identifying the photovoltaic effect,which is attributable to the Schottky junction’s built-in electric field,as the predominant mechanism.The prototype Au-WS2-graphene photodetector exhibits a remarkable light on/off ratio of 1.2×10^(6),a specific detectivity of 6.12×10^(11)cm H^(z1/2)W^(-1)with 20μs response time at 638 nm.The wide gate-tunable responsivity provides an adjustability scope,ranging from 0.9 to 3.1 A W^(-1).Notably,the device demonstrates an exceptional linear photocurrent response,with a linear dynamic range(LDR)value approximating 130 dB,which significantly surpasses that of other photodetectors based on TMDs.展开更多
基金supports from the KeyArea Research and Development Program of Guangdong Province(No.2020B0101340001)the National Natural Science Foundation of China(Nos.61888102,11834017,51901025,and 12074412)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(CAS)(No.XDB30000000)Postdoctoral Innovative Talent Support Program(No.BX2021351)。
文摘Photodetectors and optoelectronic synapses are vital for construction of artificial visual perception system.However,the hardware implementations of optoelectronic-neuromorphic devices based on conventional architecture usually suffer from poor scalability,light response range,and limited functionalities.Here,large-scale flexible monolayer MoS_(2)devices integrating photodetectors and optoelectronic synapses over the entire visible spectrum in one device have been realized,which can be used in photodetection,optical communication,artificial visual perception system,and optical artificial neural network.By modulating gate voltages,we enable MoS_(2)-based devices to be photodetectors and also optoelectronic synapses.Importantly,the MoS_(2)-based optoelectronic synapses could implement many synaptic functions and neuromorphic characteristics,such as short-term memory(STM),long-term memory(LTM),paired-pulse facilitation(PPF),long-term potentiation(LTP)/long-term depression(LTD),and“learning-experience”behavior.Furthermore,an associative learning behavior(the classical conditioning Pavlov’s dog experiment)was emulated using paired stimulation of optical and voltage pulses.These results facilitate the development of MoS_(2)-based multifunctional optoelectronic devices with a simple device structure,showing great potential for photodetection,optoelectronic neuromorphic computing,human visual systems mimicking,as well as wearable and implantable electronics.
基金the financial support provided by the Fundamental Research Funds for the Central Universities(Nos.NS2020008,NC2018001,NJ2020003,NZ2020001)the Program for Innovative Talents and Entrepreneur in Jiangsu,Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures(Nos.MCMS-I-0419G02,MCMS-I-0421K01)+2 种基金National Key Research and Development Program of China(No.2019YFA0705400)Australian Research Council Future Fellowship(No.FT160100205)DECRA Fellowship(No.DE200101622)。
文摘Metal-semiconductor diodes constructed from two-dimensional(2D)van der Waals heterostructures show excellent gate electrostatics and a large built-in electric field at the tunnel junction,which can be exploited to make highly sensitive photodetector.Here we demonstrate a metal-semiconductor photodiode constructed by the monolayer graphene(Gr)on a few-layer black phosphorus(BP).Due to the presence of a built-in potential barrier(~0.09±0.03 eV)at the Gr-BP interface,the photoresponsivity of the Gr-BP device is enhanced by a factor of 672%,and the external quantum efficiency(EQE)increases to648%from 84%of the bare BP.Electrostatic gating allows the BP channel to be switched between p-type and n-type conduction.We further demonstrate that excitation laser power can be used to control the current polarity of the Gr-BP device due to photon-induced doping.The versatility of the Gr-BP junctions in terms of electrostatic bias-induced or light-induced switching of current polarity is potentially useful for making dynamically reconfigurable digital circuits.
基金Project supported by the National Basic Research Program of China(Grant No.2016YFA0200800)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB30000000 and XDB07030100)the Sinopec Innovation Scheme(Grant No.A-527).
文摘The ability to control transport behaviors in nanostructure is crucial for usage as a fundamental research platform as well as a practical device.In this study,we report a gate-controlled crossover of electron transport behaviors using graphene nanoconstrictions as a platform.The observed transport properties span from Coulomb blockade-dominated single electron transmission to electron-wave interference-dominated quantum behavior.Such drastic modulation is achieved by utilizing a single back gate on a graphene nanoconstriction structure,where the size of nanostructure in the constriction and coupling strength of it to the electrodes can be tuned electrically.Our results indicate that electrostatic field by gate voltage upon the confined nanostructure defines both the size of the nanoconstriction as well as its interaction to electrodes.Increasing gate voltage raises Fermi level to cross the energy profile in the nanoconstriction,resulting in decreased energy barriers which affect the size of nanoconstriction and transmissivity of electrons.The gate-tunable nanoconstriction device can therefore become a potential platform to study quantum critical behaviors and enrich electronic and spintronic devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.62305077,62222514,61991440,and 62005249)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.Y2021070)+8 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB43010200)Shanghai Rising-Star Program(Grant No.20QA1410400)Shanghai Science and Technology Committee(Grant Nos.23ZR1482000,20JC1416000,and 22JC1402900)the Natural Science Foundation of Zhejiang Province(Grant No.LR22F050004)Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)Hangzhou West Science and Technology Innovation Corridor Youth ProjectExcellent Postdoctoral Research Projects of Zhejiang Province(Grant No.ZJ2021019)the Open Fund of State Key Laboratory of Infrared Physics(Grant No.SITP-NLIST-YB-2023-13)Zhejiang Provincial Natural Science Foundation(Grant No.LQ20F050005)。
文摘The heterojunction integration of two-dimensional(2D)materials via van der Waals(vdW)forces,unencumbered by lattice and processing constraints,constitutes an efficacious approach to enhance the overall optoelectronic performance of photodetectors,due to an assortment of distinctive light-matter interactions.Nonetheless,vdW heterojunction photodetectors based on transition metal dichalcogenides(TMDs)face an inevitable trade-off between low dark currents and high responsivity,curtailing the application potential of myriad novel optoelectronic components in sensing,spectral,and communication systems.In this study,we present the successful actualization of a highly sensitive,self-powered,and gate-tunable bipolar response photodetector.The mechanisms underlying photocurrent generation were scrutinized via bias-,power-,and position-dependent mapping photoresponse measurements,identifying the photovoltaic effect,which is attributable to the Schottky junction’s built-in electric field,as the predominant mechanism.The prototype Au-WS2-graphene photodetector exhibits a remarkable light on/off ratio of 1.2×10^(6),a specific detectivity of 6.12×10^(11)cm H^(z1/2)W^(-1)with 20μs response time at 638 nm.The wide gate-tunable responsivity provides an adjustability scope,ranging from 0.9 to 3.1 A W^(-1).Notably,the device demonstrates an exceptional linear photocurrent response,with a linear dynamic range(LDR)value approximating 130 dB,which significantly surpasses that of other photodetectors based on TMDs.
