Oxide materials with a non-centrosymmetric structure exhibit bulk photovoltaic effect(BPVE)but with a low cell efficiency.Over the past few years,relatively larger BPVE coefficients have been reported for two-dimensio...Oxide materials with a non-centrosymmetric structure exhibit bulk photovoltaic effect(BPVE)but with a low cell efficiency.Over the past few years,relatively larger BPVE coefficients have been reported for two-dimensional(2D)layers and stacks with asymmety-induced spontaneous polarization.Here,we report a crucial breakthrough in boosting the BPVE in 3R-MoS2 by adopting edge contact(EC)geometry using bismuth semimetal electrode.In clear contrast to the typically used top contact(TC)geometry,the EC metal which strongly adheres to the edges and the subtrates can induce a pronounced tensile strain to the 3R-MoS2,and the lateral contact geometry allows to completely access to in-plane polarization from underneath layers reachable by light,leading to>100 times of BPVE enhancement in photocurrent.We further design a 3R-MoS2/WSe2 heterojunction to demonstrate constructive coupling of BPVE with the conventional photovoltaic effect,indicating their potential in photodetectors and photovoltaic devices.展开更多
The growth of data and Internet of Things challenges traditional hardware,which encounters efficiency and power issues owing to separate functional units for sensors,memory,and computation.In this study,we designed an...The growth of data and Internet of Things challenges traditional hardware,which encounters efficiency and power issues owing to separate functional units for sensors,memory,and computation.In this study,we designed an a-phase indium selenide(a-In_(2)Se_(3))transistor,which is a two-dimensional ferroelectric semiconductor as the channel material,to create artificial optic-neural and electro-neural synapses,enabling cutting-edge processing-in-sensor(PIS)and computing-in-memory(CIM)functionalities.As an optic-neural synapse for low-level sensory processing,the a-In_(2)Se_(3)transistor exhibits a high photoresponsivity(2855 A/W)and detectivity(2.91×10^(14)Jones),facilitating efficient feature extraction.For high-level processing tasks as an electro-neural synapse,it offers a fast program/erase speed of 40 ns/50μs and ultralow energy consumption of 0.37 aJ/spike.An AI vision system using a-In_(2)Se_(3)transistors has been demonstrated.It achieved an impressive recognition accuracy of 92.63%within 12 epochs owing to the synergistic combination of the PIS and CIM functionalities.This study demonstrates the potential of the a-In_(2)Se_(3)transistor in future vision hardware,enhancing processing,power efficiency,and AI applications.展开更多
Transition metal dichalcogenides(TMDCs)are promising candidates for future optoelectronic devices accounting for their high carrier mobility and excellent quantum efficiency.However,the limited light absorption effici...Transition metal dichalcogenides(TMDCs)are promising candidates for future optoelectronic devices accounting for their high carrier mobility and excellent quantum efficiency.However,the limited light absorption efficiency in atomically thin layers significantly hinders photocarrier generation,thereby impairing the optoelectronic performance and hindering practical applications.Herein,we successfully synthesized In_(2)Se_(3)/WSe_(2) heterostructures through a typical two-step chemical vapor deposition(CVD)method.The In_(2)Se_(3) nanosheet with strong light absorption capability,serving as the light absorption layer,was integrated with the monolayer WSe_(2),enhancing the photosensitivity of WSe_(2) significantly.Upon laser irradiation with a wavelength of 520 nm,the In_(2)Se_(3)/WSe_(2) heterostructure device shows an ultrahigh photoresponsivity with a value as high as 2333.5 A/W and a remarkable detectivity reaching up to 6.7×10^(12) Jones,which is the highest among almost the reported TMDCs-based heterostructures grown via CVD even some fabricated by mechanical exfoliation(ME).Combing the advantages of CVD method such as large scale,high yield,and clean interface,the In_(2)Se_(3)/WSe_(2) heterostructures would provide a novel path for future high-performance optoelectronic device.展开更多
Small contact resistance and low Schottky barrier height(SBH)are the keys to energy-efficient electronics and optoelectronics.Two-dimensional(2D)semiconductors-based field effect transistors(FETs),holding great promis...Small contact resistance and low Schottky barrier height(SBH)are the keys to energy-efficient electronics and optoelectronics.Two-dimensional(2D)semiconductors-based field effect transistors(FETs),holding great promise for next-generation information circuits,still suffer from poor contact quality at the metal–semiconductor junction interface,which severely hinders their further applications.Here,a novel contact strategy is proposed,where Bi_(2)Te_(3)nanosheets with high conductivity were in-situ epitaxially grown on MoS_(2)as van der Waals contacts,which can effectively avoid the damage to MoS_(2)caused during the device manufacturing process,leading to a high-performance MoS_(2)FET.Moreover,the small work function difference between Bi_(2)Te_(3)and MoS_(2)(Bi_(2)Te_(3):4.31 eV,MoS_(2):4.37 eV,measured by Kelvin probe force microscopy(KPFM)),enables small band bending and Ohmic contact at the junction interface.Electrical characterizations indicate that the MoS_(2)FET device with Bi_(2)Te_(3)contacts possesses a high current on/off ratio(5×107),large effective carrier mobility(90 cm^(2)/(V·s)),and low flat-band SBH(60 meV),which is favorable as compared with MoS_(2)FET with traditional Cr/Au electrodes contacts,and superior to the vast majority of the reported chemical vapor deposition(CVD)MoS_(2)-based FET device.The demonstration of epitaxial van der Waals Bi_(2)Te_(3)contacts will facilitate the application of 2D MoS_(2)nanosheet in next-generation low-power consumption electronics and optoelectronics.展开更多
基金support from the Jockey Club Hong Kong to the JC STEM lab of 3DIC(2022-0118)the Research Grant of the Council of Hong Kong(CRS_PolyU502/22 and T46-705/23-R)+6 种基金L.-J.L.&Y.W.acknowledge the support from the University of Hong Kong and the National Key R&D Project of China(2022YFB4400100)S.Q.acknowledges the financial support from Ministry of Science and Technology of China(P222020001)National Nature Science Foundation of China(62175058)Nature Science Foundation of Hebei Province(A2022201014)Hebei Province Optoelectronic Information Materials Laboratory Performance Subsidy Fund Project(22567634H)P.C.Y.C.acknowledges support from the Research Grant of the Council of Hong Kong(27200822)the National Nature Science Foundation of China(22222905).
文摘Oxide materials with a non-centrosymmetric structure exhibit bulk photovoltaic effect(BPVE)but with a low cell efficiency.Over the past few years,relatively larger BPVE coefficients have been reported for two-dimensional(2D)layers and stacks with asymmety-induced spontaneous polarization.Here,we report a crucial breakthrough in boosting the BPVE in 3R-MoS2 by adopting edge contact(EC)geometry using bismuth semimetal electrode.In clear contrast to the typically used top contact(TC)geometry,the EC metal which strongly adheres to the edges and the subtrates can induce a pronounced tensile strain to the 3R-MoS2,and the lateral contact geometry allows to completely access to in-plane polarization from underneath layers reachable by light,leading to>100 times of BPVE enhancement in photocurrent.We further design a 3R-MoS2/WSe2 heterojunction to demonstrate constructive coupling of BPVE with the conventional photovoltaic effect,indicating their potential in photodetectors and photovoltaic devices.
基金supported by the National Natural Science Foundation of China(62104066,52221001,62090035,U19A2090,U22A20138,52372146,and 62101181)the National Key R&D Program of China(2022YFA1402501,2022YFA1204300)+6 种基金the Natural Science Foundation of Hunan Province(2021JJ20016)the Science and Technology Innovation Program of Hunan Province(2021RC3061)the Key Program of Science and Technology Department of Hunan Province(2019XK2001,2020XK2001)the Open Project Program of Wuhan National Laboratory for Optoelectronics(2020WNLOKF016)the Open Project Program of Key Laboratory of Nanodevices and Applications,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(22ZS01)the Project funded by China Postdoctoral Science Foundation(2023TQ0110)the Innovation Project of Optics Valley Laboratory(OVL2023ZD002).
文摘The growth of data and Internet of Things challenges traditional hardware,which encounters efficiency and power issues owing to separate functional units for sensors,memory,and computation.In this study,we designed an a-phase indium selenide(a-In_(2)Se_(3))transistor,which is a two-dimensional ferroelectric semiconductor as the channel material,to create artificial optic-neural and electro-neural synapses,enabling cutting-edge processing-in-sensor(PIS)and computing-in-memory(CIM)functionalities.As an optic-neural synapse for low-level sensory processing,the a-In_(2)Se_(3)transistor exhibits a high photoresponsivity(2855 A/W)and detectivity(2.91×10^(14)Jones),facilitating efficient feature extraction.For high-level processing tasks as an electro-neural synapse,it offers a fast program/erase speed of 40 ns/50μs and ultralow energy consumption of 0.37 aJ/spike.An AI vision system using a-In_(2)Se_(3)transistors has been demonstrated.It achieved an impressive recognition accuracy of 92.63%within 12 epochs owing to the synergistic combination of the PIS and CIM functionalities.This study demonstrates the potential of the a-In_(2)Se_(3)transistor in future vision hardware,enhancing processing,power efficiency,and AI applications.
基金support from the following funding:the National Key R&D Program of China(No.2022YFA1204300)the National Natural Science Foundation of China(Nos.62104066,52221001,62090035,U19A2090,U22A20138 and 51902098)+5 种基金the Natural Science Foundation of Hunan Province(No.2021JJ20016)the Science and Technology Innovation Program of Hunan Province(Nos.2021RC3061 and 2020RC2028)the Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001 and 2020XK2001)the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2020WNLOKF016)the National Postdoctoral Program for Innovative Talents(No.BX2021094)the Postdoctoral Science Foundation of China(No.2020M680112).
文摘Transition metal dichalcogenides(TMDCs)are promising candidates for future optoelectronic devices accounting for their high carrier mobility and excellent quantum efficiency.However,the limited light absorption efficiency in atomically thin layers significantly hinders photocarrier generation,thereby impairing the optoelectronic performance and hindering practical applications.Herein,we successfully synthesized In_(2)Se_(3)/WSe_(2) heterostructures through a typical two-step chemical vapor deposition(CVD)method.The In_(2)Se_(3) nanosheet with strong light absorption capability,serving as the light absorption layer,was integrated with the monolayer WSe_(2),enhancing the photosensitivity of WSe_(2) significantly.Upon laser irradiation with a wavelength of 520 nm,the In_(2)Se_(3)/WSe_(2) heterostructure device shows an ultrahigh photoresponsivity with a value as high as 2333.5 A/W and a remarkable detectivity reaching up to 6.7×10^(12) Jones,which is the highest among almost the reported TMDCs-based heterostructures grown via CVD even some fabricated by mechanical exfoliation(ME).Combing the advantages of CVD method such as large scale,high yield,and clean interface,the In_(2)Se_(3)/WSe_(2) heterostructures would provide a novel path for future high-performance optoelectronic device.
基金The authors are grateful to the National Key R&D Program of China(No.2022YFA1402501)the National Natural Science Foundation of China(Nos.51902098,62090035,U22A2013,and U19A2090)+3 种基金the Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001 and 2020XK2001)the Science and Technology Innovation Program of Hunan Province(Nos.2021RC3061,2020RC2028,and 2021RC2042)the Natural Science Foundation of Hunan Province(No.2021JJ20016)the Project funded by China Postdoctoral Science Foundation(Nos.2020M680112 and 2021M690953).
文摘Small contact resistance and low Schottky barrier height(SBH)are the keys to energy-efficient electronics and optoelectronics.Two-dimensional(2D)semiconductors-based field effect transistors(FETs),holding great promise for next-generation information circuits,still suffer from poor contact quality at the metal–semiconductor junction interface,which severely hinders their further applications.Here,a novel contact strategy is proposed,where Bi_(2)Te_(3)nanosheets with high conductivity were in-situ epitaxially grown on MoS_(2)as van der Waals contacts,which can effectively avoid the damage to MoS_(2)caused during the device manufacturing process,leading to a high-performance MoS_(2)FET.Moreover,the small work function difference between Bi_(2)Te_(3)and MoS_(2)(Bi_(2)Te_(3):4.31 eV,MoS_(2):4.37 eV,measured by Kelvin probe force microscopy(KPFM)),enables small band bending and Ohmic contact at the junction interface.Electrical characterizations indicate that the MoS_(2)FET device with Bi_(2)Te_(3)contacts possesses a high current on/off ratio(5×107),large effective carrier mobility(90 cm^(2)/(V·s)),and low flat-band SBH(60 meV),which is favorable as compared with MoS_(2)FET with traditional Cr/Au electrodes contacts,and superior to the vast majority of the reported chemical vapor deposition(CVD)MoS_(2)-based FET device.The demonstration of epitaxial van der Waals Bi_(2)Te_(3)contacts will facilitate the application of 2D MoS_(2)nanosheet in next-generation low-power consumption electronics and optoelectronics.
