Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency a...Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency and rapid recombination of photoexcited carriers, leading to poor photodetection performance. Here, inspired by the photogating effect, we demonstrated a highly sensitive photodetector based on graphene/WSe_(2) vertical heterostructure where the WSe_(2) layer acts as both the light absorption layer and the localized grating layer. The graphene conductive channel is induced to produce more carriers by capacitive coupling. Due to the strong light absorption and high external quantum efficiency of multilayer WSe_(2), as well as the high carrier mobility of graphene, a high photocurrent is generated in the vertical heterostructure. As a result, the photodetector exhibits ultra-high responsivity of 3.85×10~4A/W and external quantum efficiency of 1.3 × 10~7%.This finding demonstrates that photogating structures can effectively enhance the sensitivity of graphene-based photodetectors and may have great potential applications in future optoelectronic devices.展开更多
Recently,it has been proposed that spin torque oscillators(STOs)and spin torque diodes could be used as artificial neurons and synapses to directly process microwave signals,which could lower latency and power consump...Recently,it has been proposed that spin torque oscillators(STOs)and spin torque diodes could be used as artificial neurons and synapses to directly process microwave signals,which could lower latency and power consumption greatly.However,one critical challenge is to make the microwave emission frequency of the STO stay constant with a varying input current.In this work,we study the microwave emission characteristics of STOs based on magnetic tunnel junction with MgO cap layer.By applying a small magnetic field,we realize the invariability of the microwave emission frequency of the STO,making it qualified to act as artificial neuron.Furthermore,we have simulated an artificial neural network using STO neuron to recognize the handwritten digits in the Mixed National Institute of Standards and Technology database,and obtained a high accuracy of 92.28%.Our work paves the way for the development of radio-frequency-oriented neuromorphic computing systems.展开更多
Photodetectors based on two-dimensional materials have attracted much attention because of their unique structure and outstanding performance.The response speed of single ReS_(2)photodetector is slow exceptionally,the...Photodetectors based on two-dimensional materials have attracted much attention because of their unique structure and outstanding performance.The response speed of single ReS_(2)photodetector is slow exceptionally,the heterostructure could improves the response speed of ReS_(2)-based photodetector,but the photodetectors responsivity is reduced greatly,which restricts the development of ReS_(2).In this paper,a vertically structured ReS_(2)/SnS_(2)van der Waals heterostructure photodetectors is prepared,using ReS_(2)as the transport layer and SnS_(2)as the light absorbing layer to regulate the channel current.The device has an ultra-high photoconductive gain of 10^(10),which exhibits an ultra-high responsivity of4706 A/W under 365-nm illumination and response speed in seconds,and has an ultra-high external quantum efficiency of1.602×10^(6)%and a high detectivity of 5.29×10^(12)jones.The study for ReS_(2)-based photodetector displays great potential for developing future optoelectronic devices.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No.11974379)the National Key Basic Research and Development Program of China (Grant No.2021YFC2203400)Jiangsu Vocational Education Integrated Circuit Technology “Double-Qualified” Famous Teacher Studio (Grant No.2022-13)。
文摘Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency and rapid recombination of photoexcited carriers, leading to poor photodetection performance. Here, inspired by the photogating effect, we demonstrated a highly sensitive photodetector based on graphene/WSe_(2) vertical heterostructure where the WSe_(2) layer acts as both the light absorption layer and the localized grating layer. The graphene conductive channel is induced to produce more carriers by capacitive coupling. Due to the strong light absorption and high external quantum efficiency of multilayer WSe_(2), as well as the high carrier mobility of graphene, a high photocurrent is generated in the vertical heterostructure. As a result, the photodetector exhibits ultra-high responsivity of 3.85×10~4A/W and external quantum efficiency of 1.3 × 10~7%.This finding demonstrates that photogating structures can effectively enhance the sensitivity of graphene-based photodetectors and may have great potential applications in future optoelectronic devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974379 and 12204357)K.C.Wong Education Foundation(Grant No.GJTD2019-14)+2 种基金Jiangxi Province“Double Thousand Plan”(Grant No.S2019CQKJ2638)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.22KB140017)Wuxi University Research Start-up Fund for Introduced Talents(Grant No.2022r006)。
文摘Recently,it has been proposed that spin torque oscillators(STOs)and spin torque diodes could be used as artificial neurons and synapses to directly process microwave signals,which could lower latency and power consumption greatly.However,one critical challenge is to make the microwave emission frequency of the STO stay constant with a varying input current.In this work,we study the microwave emission characteristics of STOs based on magnetic tunnel junction with MgO cap layer.By applying a small magnetic field,we realize the invariability of the microwave emission frequency of the STO,making it qualified to act as artificial neuron.Furthermore,we have simulated an artificial neural network using STO neuron to recognize the handwritten digits in the Mixed National Institute of Standards and Technology database,and obtained a high accuracy of 92.28%.Our work paves the way for the development of radio-frequency-oriented neuromorphic computing systems.
基金the National Natural Science Foundation of China(Grant Nos.61574011,60908012,61575008,61775007,61731019,61874145,62074011,and 62134008)the Beijing Natural Science Foundation(Grant Nos.4182015,4172011,and 4202010)Beijing Nova Program(Grant No.Z201100006820096)。
文摘Photodetectors based on two-dimensional materials have attracted much attention because of their unique structure and outstanding performance.The response speed of single ReS_(2)photodetector is slow exceptionally,the heterostructure could improves the response speed of ReS_(2)-based photodetector,but the photodetectors responsivity is reduced greatly,which restricts the development of ReS_(2).In this paper,a vertically structured ReS_(2)/SnS_(2)van der Waals heterostructure photodetectors is prepared,using ReS_(2)as the transport layer and SnS_(2)as the light absorbing layer to regulate the channel current.The device has an ultra-high photoconductive gain of 10^(10),which exhibits an ultra-high responsivity of4706 A/W under 365-nm illumination and response speed in seconds,and has an ultra-high external quantum efficiency of1.602×10^(6)%and a high detectivity of 5.29×10^(12)jones.The study for ReS_(2)-based photodetector displays great potential for developing future optoelectronic devices.
