Aramid nanofiber(ANF)-based composites have drawn tremendous interest in high-voltage electrical systems due to their superior insulation strength,thermal stability,and mechanical endurance.However,the filler agglomer...Aramid nanofiber(ANF)-based composites have drawn tremendous interest in high-voltage electrical systems due to their superior insulation strength,thermal stability,and mechanical endurance.However,the filler agglomeration and interface compatibility have retarded further improvement of the dielectric performance.Herein,the nano-titanium dioxide(TiO_(2))particles treated by aminopropyl triethoxysilane(APTES)serve as the inorganic fillers,which are doped in the ANF to prepare the composite nano-paper via the blade coating method.The electrostatic interaction between the ANF and fillers highly promotes their uniform distribution.Compared to the pure ANF paper,the composite paper has a denser structure with reduced pores and defects,which significantly improves its dielectric performance with inhibited partial discharge development.At a filler loading of 3 wt%(mass fraction),the breakdown strength is increased by 70.5%to a maximum value of 358.1 kV/mm,while the bulk conductivity is minimised to 5.2×10^(-17)S/m,representing an 88.1%decrease.By analysing the energy band structure of each component,energy barriers at the interface for electrons(1.48 eV)and holes(0.40 eV)are determined.These values indicate deepened trap energy levels,which greatly strengthen the carrier trapping effect for improved dielectric performance.展开更多
Quantum tunneling with band-structure engineering has been feasibly developed for many applications in electrical,optoelectrical,and magnetic devices.It relies on layer-by-layer design and fabrication,which is an inte...Quantum tunneling with band-structure engineering has been feasibly developed for many applications in electrical,optoelectrical,and magnetic devices.It relies on layer-by-layer design and fabrication,which is an interdisciplinary research field covering material science and technology.Ever since the discovery of two-dimensional(2 D)layered materials,tunneling devices based on 2D van der Waals(vd W)heterostructures have been extensively studied as potential next-generation devices.2 D materials are thin at the atomic scale and extremely flat without surface dangling bonds.Because of these unique characteristics,2 D vd W heterostructures offer superior tunneling performance that reaches the benchmark of traditional Si technology and possess additional ability to scale down device size.Here,we comprehensively review quantum tunneling in 2 D vd W heterostructures,in addition to their unique mechanisms and applications.Moreover,we analyze the possibilities and challenges currently faced by 2 D tunneling devices and provide a perspective on their exploitation for advanced future applications.The investigation of technology-and performancecontrol of 2 D tunneling devices is at their beginning stages;however,these devices should emerge as competitive candidates for realizing low-power supply,fast-speed capability,and high-frequency operating devices.展开更多
Van der Waals(vdW)heterojunctions,with their unique electronic and optoelectronic properties,have become promising candidates for photodetector applications.Amplifying the contribution of the depletion region in vdW h...Van der Waals(vdW)heterojunctions,with their unique electronic and optoelectronic properties,have become promising candidates for photodetector applications.Amplifying the contribution of the depletion region in vdW heterojunction,which would enhance both of the collection efficiency and speed of the photogenerated carriers,presents an effective strategy for achieving high performance vdW heterojunction photodetectors.Herein,a fully depleted vdW heterojunction photodetector is built on two-dimensional(2D)semiconductor materials(GaTe and InSe)layered on a pattered bottom electrode in vertical structure,in which the generation and motion of carriers are exclusively achieved in the depletion region.Attributed to the intrinsic built-in electric field,the elimination of series resistance and the depletion region confinement of carriers,the as-fabricated photodetector exhibits prominent photovoltaic properties with a high open-circuit voltage of 0.465 V,as well as photoresponse characteristics with outstanding responsivity,detectivity and photoresponse speed of 63.7 A/W,3.88×10^(13)Jones,and 32.7 ms respectively.The overall performance of this fully depleted GaTe/InSe vdW heterojunctions photodetectors are ranking high among the top level of 2D materials based photodetectors.It indicates the device architecture can provide new opportunities for the fabrication of high-performance photodetectors.展开更多
Although photodetection based on two-dimensional(2D)van der Waals(vdWs)P-N heterojunction has attracted extensive attention recently,their low responsivity(R)due to the lack of carrier gain mechanism in reverse bias o...Although photodetection based on two-dimensional(2D)van der Waals(vdWs)P-N heterojunction has attracted extensive attention recently,their low responsivity(R)due to the lack of carrier gain mechanism in reverse bias or zero bias operation hinders their applications in advanced photodetection area.Here,a black phosphorus/rhodamine 6G/molybdenum disulfide(BP/R6G/MoS_(2))photodiode with high responsivity at reverse bias or zero bias has been achieved by using interfacial charge transfer of R6G molecules assembled between heterojunction layers.The formed vdWs interface achieves high performance photoresponse by efficiently separating the additional photogenerated electrons and holes generated by R6G molecules.The devices sensitized by the dye molecule R6G exhibit enhanced photodetection performance without sacrificing the photoresponse speed.Among them,the R increased by 14.8-20.4 times,and the specific detectivity(D^(*))increased by 24.9-34.4 times.The strategy based on interlayer assembly of dye molecules proposed here may pave a new way for realizing high-performance photodetection based on 2D vdWs heterojunctions with high responsivity and fast response speed.展开更多
Neutron-transmutation doping(NTD)has been demonstrated for the first time in this work for substitutional introduction of tin(Sn)shallow donors into two-dimensional(2D)layered indium selenide(InSe)to manipulate electr...Neutron-transmutation doping(NTD)has been demonstrated for the first time in this work for substitutional introduction of tin(Sn)shallow donors into two-dimensional(2D)layered indium selenide(InSe)to manipulate electron transfer and charge carrier dynamics.Multidisciplinary study including density functional theory,transient optical absorption,and FET devices have been carried out to reveal that the field effect electron mobility of the fabricated phototransistor is increased 100-fold due to the smaller electron effective mass and longer electron life time in the Sn-doped InSe.The responsivity of the Sn-doped InSe based phototransistor is accordingly enhanced by about 50 times,being as high as 397 A/W.The results show that NTD is a highly effective and controllable doping method,possessing good compatibility with the semiconductor manufacturing process,even after device fabrication,and can be carried out without introducing any contamination,which is radically different from traditional doping methods.展开更多
The interface between oxide/oxide layers shows an inhomogeneous charge transport behavior,which reveals a high conductivity owing to interface-doped.One typical example is the hetero-interface between ZnO film and oth...The interface between oxide/oxide layers shows an inhomogeneous charge transport behavior,which reveals a high conductivity owing to interface-doped.One typical example is the hetero-interface between ZnO film and other wide band gap oxides(e.g.,Al_(2)O_(3),TiO_(2),and HfO_(2)).It is thus quite evident that the ZnO/other oxides hetero-interface contains high density electron carriers effectively screening the gate-induced electric field.Thus,an extremely weak gate modulation in ZnO film was showed,resulting in very low on/off ratio of 1.69 in top-gate field-effect-transistor(TG-FET)configuration.So,to extend the usage of ZnO TG-FET is not quite possible toward further practical application.Herein,we clarified the correlation of inhomogeneous region in oxide/oxide hetero-junction by systematically study.Our work suggests that a self-assembly of molecules(SAM)buffer layer is suitable for tuning the inhomogeneous charge transport in ZnO film,which not only reduces the interface trap density,but also effectively enhances the gate electric field modulation at the hetero-interface.We further report the robust fabrication of TG-FET arrays based on ZnO thin film,using an ultra-thin alkylphosphonic acid molecule monolayer as buffer layer.Our device demonstrates a pronounced ultrahigh on/off ratio of≥10^(8),which is 8-order of magnitude higher than that of a device without buffer layer.For the highly reliable arrays,our device exhibits a high yield of over 93%with an average on/off ratio of^10^(7) across the entire wafer scale,mobility(18.5 cm^(2)/(V·s)),an extended bias-stressing(~2,000 s)and long-stability(~150 days)under ambient conditions.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:62104153Fundamental Research Funds for the Central Universities,Grant/Award Numbers:2023MS002,2023MS006。
文摘Aramid nanofiber(ANF)-based composites have drawn tremendous interest in high-voltage electrical systems due to their superior insulation strength,thermal stability,and mechanical endurance.However,the filler agglomeration and interface compatibility have retarded further improvement of the dielectric performance.Herein,the nano-titanium dioxide(TiO_(2))particles treated by aminopropyl triethoxysilane(APTES)serve as the inorganic fillers,which are doped in the ANF to prepare the composite nano-paper via the blade coating method.The electrostatic interaction between the ANF and fillers highly promotes their uniform distribution.Compared to the pure ANF paper,the composite paper has a denser structure with reduced pores and defects,which significantly improves its dielectric performance with inhibited partial discharge development.At a filler loading of 3 wt%(mass fraction),the breakdown strength is increased by 70.5%to a maximum value of 358.1 kV/mm,while the bulk conductivity is minimised to 5.2×10^(-17)S/m,representing an 88.1%decrease.By analysing the energy band structure of each component,energy barriers at the interface for electrons(1.48 eV)and holes(0.40 eV)are determined.These values indicate deepened trap energy levels,which greatly strengthen the carrier trapping effect for improved dielectric performance.
基金supported by China Postdoctoral Science Foundation (2020TQ0199 and 2020M682880)the Science and Technology Innovation Commission of Shenzhen (JCYJ20180305125345378)+1 种基金Guangdong Basic and Applied Basic Research Foundation (2020B1515020051)the National Natural Science Foundation of China (51702219 and 61975134)
文摘Quantum tunneling with band-structure engineering has been feasibly developed for many applications in electrical,optoelectrical,and magnetic devices.It relies on layer-by-layer design and fabrication,which is an interdisciplinary research field covering material science and technology.Ever since the discovery of two-dimensional(2 D)layered materials,tunneling devices based on 2D van der Waals(vd W)heterostructures have been extensively studied as potential next-generation devices.2 D materials are thin at the atomic scale and extremely flat without surface dangling bonds.Because of these unique characteristics,2 D vd W heterostructures offer superior tunneling performance that reaches the benchmark of traditional Si technology and possess additional ability to scale down device size.Here,we comprehensively review quantum tunneling in 2 D vd W heterostructures,in addition to their unique mechanisms and applications.Moreover,we analyze the possibilities and challenges currently faced by 2 D tunneling devices and provide a perspective on their exploitation for advanced future applications.The investigation of technology-and performancecontrol of 2 D tunneling devices is at their beginning stages;however,these devices should emerge as competitive candidates for realizing low-power supply,fast-speed capability,and high-frequency operating devices.
基金supported by the State Key Research Development Program of China(Grant No.2019YFB2203503)National Natural Science Fund(Grant Nos.61875138,61961136001,62104153,62105211 and U1801254)+3 种基金Natural Science Foundation of Guangdong Province(2018B030306038 and 2020A1515110373)Science and Technology Projects in Guangzhou(no.202201000002)Science and Technology Innovation Commission of Shenzhen(JCYJ20180507182047316 and 20200805132016001)Natural Science Foundation of Jilin Province(Grant No.YDZJ202201ZYTS429)。
文摘Van der Waals(vdW)heterojunctions,with their unique electronic and optoelectronic properties,have become promising candidates for photodetector applications.Amplifying the contribution of the depletion region in vdW heterojunction,which would enhance both of the collection efficiency and speed of the photogenerated carriers,presents an effective strategy for achieving high performance vdW heterojunction photodetectors.Herein,a fully depleted vdW heterojunction photodetector is built on two-dimensional(2D)semiconductor materials(GaTe and InSe)layered on a pattered bottom electrode in vertical structure,in which the generation and motion of carriers are exclusively achieved in the depletion region.Attributed to the intrinsic built-in electric field,the elimination of series resistance and the depletion region confinement of carriers,the as-fabricated photodetector exhibits prominent photovoltaic properties with a high open-circuit voltage of 0.465 V,as well as photoresponse characteristics with outstanding responsivity,detectivity and photoresponse speed of 63.7 A/W,3.88×10^(13)Jones,and 32.7 ms respectively.The overall performance of this fully depleted GaTe/InSe vdW heterojunctions photodetectors are ranking high among the top level of 2D materials based photodetectors.It indicates the device architecture can provide new opportunities for the fabrication of high-performance photodetectors.
基金This work was supported by National Key Research and Development Project(No.2019YFB2203503)the National Natural Science Foundation of China(No.62105211)+8 种基金China Postdoctoral Science Foundation(Nos.2021M702242 and 2022T150431)Natural Science Foundation of Guangdong Province(Nos.2018B030306038 and 2020A1515110373)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515010649)Science and Technology Projects in Guangzhou(No.202201000002)Science and Technology Innovation Commission of Shenzhen(Nos.JCYJ20180507182047316,20200805132016001,and JCYJ20200109105608771)Natural Science Foundation of Jilin Province(No.YDZJ202201ZYTS429)NTUT-SZU Joint Research Program(No.2021008)Authors acknowledge support and funding of King Khalid University through Research Center for Advanced Materials Science(RCAMS)(No.RCAMS/KKU/0010/21)The authors also acknowledge the Photonics Center of Shenzhen University for technical support.
文摘Although photodetection based on two-dimensional(2D)van der Waals(vdWs)P-N heterojunction has attracted extensive attention recently,their low responsivity(R)due to the lack of carrier gain mechanism in reverse bias or zero bias operation hinders their applications in advanced photodetection area.Here,a black phosphorus/rhodamine 6G/molybdenum disulfide(BP/R6G/MoS_(2))photodiode with high responsivity at reverse bias or zero bias has been achieved by using interfacial charge transfer of R6G molecules assembled between heterojunction layers.The formed vdWs interface achieves high performance photoresponse by efficiently separating the additional photogenerated electrons and holes generated by R6G molecules.The devices sensitized by the dye molecule R6G exhibit enhanced photodetection performance without sacrificing the photoresponse speed.Among them,the R increased by 14.8-20.4 times,and the specific detectivity(D^(*))increased by 24.9-34.4 times.The strategy based on interlayer assembly of dye molecules proposed here may pave a new way for realizing high-performance photodetection based on 2D vdWs heterojunctions with high responsivity and fast response speed.
基金State Key Research Development Program of China(Grant No.2019YFB2203503)National Natural Science Fund(Grant Nos.61875138,61961136001,62104153,62105211 and U1801254)+2 种基金Natural Science Foundation of Guangdong Province(2018B030306038 and 2020A1515110373)Science and Technology Innovation Commission of Shenzhen(JCYJ20180507182047316 and 20200805132016001)Postdoctoral Science Foundation of China(No.2021M702237)。
文摘Neutron-transmutation doping(NTD)has been demonstrated for the first time in this work for substitutional introduction of tin(Sn)shallow donors into two-dimensional(2D)layered indium selenide(InSe)to manipulate electron transfer and charge carrier dynamics.Multidisciplinary study including density functional theory,transient optical absorption,and FET devices have been carried out to reveal that the field effect electron mobility of the fabricated phototransistor is increased 100-fold due to the smaller electron effective mass and longer electron life time in the Sn-doped InSe.The responsivity of the Sn-doped InSe based phototransistor is accordingly enhanced by about 50 times,being as high as 397 A/W.The results show that NTD is a highly effective and controllable doping method,possessing good compatibility with the semiconductor manufacturing process,even after device fabrication,and can be carried out without introducing any contamination,which is radically different from traditional doping methods.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-2018R1A2B2008069)Multi-Ministry Collaborative R&D Program through the National Research Foundation of Korea,funded by KNPA,MSIT,MOTIE,ME,and NFA(No.2017M3D9A1073539)+1 种基金supported by the Bio&Medical Technology Development Program of the National Research Foundation(NRF)funded by the Ministry of Science&ICT(No.NRF-2020M3A9E4039241)support from the Institute for Basic Science(No.IBS-R011-D1).
文摘The interface between oxide/oxide layers shows an inhomogeneous charge transport behavior,which reveals a high conductivity owing to interface-doped.One typical example is the hetero-interface between ZnO film and other wide band gap oxides(e.g.,Al_(2)O_(3),TiO_(2),and HfO_(2)).It is thus quite evident that the ZnO/other oxides hetero-interface contains high density electron carriers effectively screening the gate-induced electric field.Thus,an extremely weak gate modulation in ZnO film was showed,resulting in very low on/off ratio of 1.69 in top-gate field-effect-transistor(TG-FET)configuration.So,to extend the usage of ZnO TG-FET is not quite possible toward further practical application.Herein,we clarified the correlation of inhomogeneous region in oxide/oxide hetero-junction by systematically study.Our work suggests that a self-assembly of molecules(SAM)buffer layer is suitable for tuning the inhomogeneous charge transport in ZnO film,which not only reduces the interface trap density,but also effectively enhances the gate electric field modulation at the hetero-interface.We further report the robust fabrication of TG-FET arrays based on ZnO thin film,using an ultra-thin alkylphosphonic acid molecule monolayer as buffer layer.Our device demonstrates a pronounced ultrahigh on/off ratio of≥10^(8),which is 8-order of magnitude higher than that of a device without buffer layer.For the highly reliable arrays,our device exhibits a high yield of over 93%with an average on/off ratio of^10^(7) across the entire wafer scale,mobility(18.5 cm^(2)/(V·s)),an extended bias-stressing(~2,000 s)and long-stability(~150 days)under ambient conditions.
