Photoelectric synaptic devices have been considered as one of the key components in artificial neuromorphic systems due to their excellent capability to emulate the functions of visual neurons,such as light perception...Photoelectric synaptic devices have been considered as one of the key components in artificial neuromorphic systems due to their excellent capability to emulate the functions of visual neurons,such as light perception and image processing.Herein,we demonstrate an optically-stimulated artificial synapse with a clear photoresponse from ultraviolet to visible light,which is established on a novel heterostructure consisting of monocrystalline Cs2AgBiBr6 perovskite and indium–gallium–zinc oxide(IGZO)thin film.As compared with pure IGZO,the heterostructure significantly enhances the photoresponse and corresponding synaptic plasticity of the devices,which originate from the superior visible absorption of single-crystal Cs2AgBiBr6 and effective interfacial charge transfer from Cs2AgBiBr6 to IGZO.A variety of synaptic behaviors are realized on the fabricated thin-film transistors,including excitatory postsynaptic current,paired pulse facilitation,short-term,and long-term plasticity.Furthermore,an artificial neural network is simulated based on the photonic potentiation and electrical depression effects of synaptic devices,and an accuracy rate up to 83.8%±1.2%for pattern recognition is achieved.This finding promises a simple and efficient way to construct photoelectric synaptic devices with tunable spectrum for future neuromorphic applications.展开更多
Oxidation resistance coatings of Ir-40 at.% Zr and Ir were produced onto Mo substrates by double glow plasma technology. The oxidation resistances of the coatings were evaluated at high temperature. Ir-Zr coating cons...Oxidation resistance coatings of Ir-40 at.% Zr and Ir were produced onto Mo substrates by double glow plasma technology. The oxidation resistances of the coatings were evaluated at high temperature. Ir-Zr coating consisted of two layers： the primary layer close to the substrate was composed of dense columnar grains and the second layer was composed of dense grains of nanometric size. The mass gain of Ir coating above 800℃ was about 1.35% due to the formation of solid IrO2. The mass loss of Ir coating was about 5.3% due to the formation of gaseous oxide IrO3 when being held at 1227 ℃ for 30 min. The substrate was protected more effectively by multilayer than monolayer coating of Ir in oxidizing environment. The Ir-Zr coating was well bonded to the substrate after oxidation at 800℃. After oxidation at 1000℃, the Ir-Zr coating was poorly bonded to the substrate. The oxidation resistance of Ir-Zr coating was poor due to high content of Zr.展开更多
Broken-gap(type-Ⅲ)two-dimensional(2D)van der Waals heterostructures(vdWHs)offer an ideal platform for interband tunneling devices due to their broken-gap band offset and sharp band edge.Here,we demonstrate an efficie...Broken-gap(type-Ⅲ)two-dimensional(2D)van der Waals heterostructures(vdWHs)offer an ideal platform for interband tunneling devices due to their broken-gap band offset and sharp band edge.Here,we demonstrate an efficient control of energy band alignment in a typical type-ⅢvdWH,which is composed of vertically-stacked molybdenum telluride(MoTe2)and tin diselenide(SnSe2),via both electrostatic and optical modulation.By a single electrostatic gating with hexagonal boron nitride(hBN)as the dielectric,a variety of electrical transport characteristics including forward rectifying,Zener tunneling,and backward rectifying are realized on the same heterojunction at low gate voltages of±1 V.In particular,the heterostructure can function as an Esaki tunnel diode with a room-temperature negative differential resistance.This great tunability originates from the atomicallyflat and inert surface of h-BN that significantly suppresses the interfacial trap scattering and strain effects.Upon the illumination of an 885 nm laser,the band alignment of heterojunction can be further tuned to facilitate the direct tunneling of photogenerated charge carriers,which leads to a high photocurrent on/off ratio of>105 and a competitive photodetectivity of 1.03×1012 Jones at zero bias.Moreover,the open-circuit voltage of irradiated heterojunction can be switched from positive to negative at opposite gate voltages,revealing a transition from accumulation mode to depletion mode.Our findings not only promise a simple strategy to tailor the bands of type-ⅢvdWHs but also provide an in-depth understanding of interlayer tunneling for future low-power electronic and optoelectronic applications.展开更多
基金Shi Y.M.and Han C.acknowledge the support from the National Natural Science Foundation of China(Nos.61874074 and 62004128)the Fundamental Research Foundation of Shenzhen(Nos.JCYJ20170817101100705 and JCYJ20190808152607389)+5 种基金the Key Project of Department of Education of Guangdong Province(No.2016KZDXM008)Li H.N.acknowledges the support from the Natural Science Foundation of SZU(No.2017011)the Science and Technology Project of Shenzhen(No.JCYJ20170817100111548)This research is supported by Singapore Ministry of Education under its AcRF Tier 2(No.MOE-T2EP50220-0001)the Shenzhen Peacock Plan(No.KQTD2016053112042971)the postgraduate innovation development fund project of Shenzhen University(No.315-0000470527).
文摘Photoelectric synaptic devices have been considered as one of the key components in artificial neuromorphic systems due to their excellent capability to emulate the functions of visual neurons,such as light perception and image processing.Herein,we demonstrate an optically-stimulated artificial synapse with a clear photoresponse from ultraviolet to visible light,which is established on a novel heterostructure consisting of monocrystalline Cs2AgBiBr6 perovskite and indium–gallium–zinc oxide(IGZO)thin film.As compared with pure IGZO,the heterostructure significantly enhances the photoresponse and corresponding synaptic plasticity of the devices,which originate from the superior visible absorption of single-crystal Cs2AgBiBr6 and effective interfacial charge transfer from Cs2AgBiBr6 to IGZO.A variety of synaptic behaviors are realized on the fabricated thin-film transistors,including excitatory postsynaptic current,paired pulse facilitation,short-term,and long-term plasticity.Furthermore,an artificial neural network is simulated based on the photonic potentiation and electrical depression effects of synaptic devices,and an accuracy rate up to 83.8%±1.2%for pattern recognition is achieved.This finding promises a simple and efficient way to construct photoelectric synaptic devices with tunable spectrum for future neuromorphic applications.
基金supported by the National Natural Science Foundation of China (No. 50872055/E020703)the Fundamental Research Funds for the Central Universities+1 种基金the Funding for Outstanding Doctoral Dissertation in NUAA (No. BCXJ11-09)the Funding of Jiangsu Innovation Program for Graduate Education (No. CXLX11 0207)
文摘Oxidation resistance coatings of Ir-40 at.% Zr and Ir were produced onto Mo substrates by double glow plasma technology. The oxidation resistances of the coatings were evaluated at high temperature. Ir-Zr coating consisted of two layers： the primary layer close to the substrate was composed of dense columnar grains and the second layer was composed of dense grains of nanometric size. The mass gain of Ir coating above 800℃ was about 1.35% due to the formation of solid IrO2. The mass loss of Ir coating was about 5.3% due to the formation of gaseous oxide IrO3 when being held at 1227 ℃ for 30 min. The substrate was protected more effectively by multilayer than monolayer coating of Ir in oxidizing environment. The Ir-Zr coating was well bonded to the substrate after oxidation at 800℃. After oxidation at 1000℃, the Ir-Zr coating was poorly bonded to the substrate. The oxidation resistance of Ir-Zr coating was poor due to high content of Zr.
基金the National Natural Science Foundation of China(No.62004128)Fundamental Research Foundation of Shenzhen(No.JCYJ20190808152607389)the technical support from the Photonics Center of Shenzhen University.
文摘Broken-gap(type-Ⅲ)two-dimensional(2D)van der Waals heterostructures(vdWHs)offer an ideal platform for interband tunneling devices due to their broken-gap band offset and sharp band edge.Here,we demonstrate an efficient control of energy band alignment in a typical type-ⅢvdWH,which is composed of vertically-stacked molybdenum telluride(MoTe2)and tin diselenide(SnSe2),via both electrostatic and optical modulation.By a single electrostatic gating with hexagonal boron nitride(hBN)as the dielectric,a variety of electrical transport characteristics including forward rectifying,Zener tunneling,and backward rectifying are realized on the same heterojunction at low gate voltages of±1 V.In particular,the heterostructure can function as an Esaki tunnel diode with a room-temperature negative differential resistance.This great tunability originates from the atomicallyflat and inert surface of h-BN that significantly suppresses the interfacial trap scattering and strain effects.Upon the illumination of an 885 nm laser,the band alignment of heterojunction can be further tuned to facilitate the direct tunneling of photogenerated charge carriers,which leads to a high photocurrent on/off ratio of>105 and a competitive photodetectivity of 1.03×1012 Jones at zero bias.Moreover,the open-circuit voltage of irradiated heterojunction can be switched from positive to negative at opposite gate voltages,revealing a transition from accumulation mode to depletion mode.Our findings not only promise a simple strategy to tailor the bands of type-ⅢvdWHs but also provide an in-depth understanding of interlayer tunneling for future low-power electronic and optoelectronic applications.
