Two-dimensional(2D)materials have been widely used in optoelectronic detection due to their excellent physical properties.Nevertheless,there has been comparatively little focus on the differentiation of light-matter i...Two-dimensional(2D)materials have been widely used in optoelectronic detection due to their excellent physical properties.Nevertheless,there has been comparatively little focus on the differentiation of light-matter interactions across distinct channel paths within the same 2D material,as well as on the photoelectric characteristics exhibited by the surface,vertical,and bottom of device.In this paper,dual-parallel device structures utilizing 2Dα-In_(2)Se_(3) semiconductors are fabricated with four conductive channels named by bottom-horizontal channel(BHC),middle-vertical channel(MVC),surface-quasi-horizontal channel(SQHC),and surface-horizontal channel(SHC)devices.The SHC device exhibits superior optical response of 101 A/W and external quantum efficiency of 1.857×104%across all conductive channels,which is over 32 times greater than that of BHC device.The SHC device boasts a fast response time of 41 ms,comparable to 32 ms offered by the nanoscale channel of the MVC device,and has a slow decay time of 319 ms similar to the 424 ms that comes with the longest channel of the SQHC device.The SHC device has the highest degree of learning and the lowest forgetting rate compared to the other three channels.Optoelectronic synapses based on dual-parallelα-In_(2)Se_(3) device can also mimic biological color image perception and memory functions,which can be used to visually determine the synaptic function of the device.In this work,on top of the excellent optoelectronic and semiconducting properties of the van der Waals semiconductorα-In2Se3,the advantages offered by the device structure are further explored to promote the development of integrated optoelectronics.展开更多
Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β...Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.展开更多
The layer-dependent properties are still unclarified in two-dimensional(2D)vertical heterostructures.In this study,we layer-bylayer deposited semimetalβ-In2Se3 on monolayer MoS2 to form verticalβ-In2Se3/MoS2 heteros...The layer-dependent properties are still unclarified in two-dimensional(2D)vertical heterostructures.In this study,we layer-bylayer deposited semimetalβ-In2Se3 on monolayer MoS2 to form verticalβ-In2Se3/MoS2 heterostructures by chemical vapor deposition.The defect-mediated nucleation mechanism inducesβ-In2Se3 nanosheets to grow on monolayer MoS2,and the layer number of stackedβ-In2Se3 can be precisely regulated from 1 layer(L)to 13 L by prolonging the growth time.Theβ-In2Se3/MoS2 heterostructures reveal tunable type-Ⅱband alignment arrangement by altering the layer number ofβ-In2Se3,which optimizes the internal electron transfer.Meanwhile,the edge atomic structure ofβ-In2Se3 stacking on monolayer MoS2 shows the reconstruction derived from large lattice mismatch(~29%),and the presence ofβ-In2Se3 also further increases the electrical conductivity ofβ-In2Se3/MoS2 heterostructures.Attributed to abundant layer-dependent edge active sites,edge reconstruction,improved hydrophilicity,and high electrical conductivity ofβ-In2Se3/MoS2 heterostructures,the edge ofβ-In2Se3/MoS2 heterostructures exhibits excellent electrocatalytic hydrogen evolution performance.Lower onset potential and smaller Tafel slope can be observed at the edge of monolayer MoS2 coupled with 13-Lβ-In2Se3.Hence,the outstanding conductive layers coupled with edge reconstruction in 2D vertical heterostructures play decisive roles in the optimization of electron energy levels and improvement of layer-dependent catalytic performance.展开更多
Recently,because of excellent electrical conductivities and many active sites,transition metal sulfides have been utilized as efficient electrodes for supercapacitors.Herein,we synthesize hierarchical MoS2/Ni3S2 struc...Recently,because of excellent electrical conductivities and many active sites,transition metal sulfides have been utilized as efficient electrodes for supercapacitors.Herein,we synthesize hierarchical MoS2/Ni3S2 structures grown on nickel foam by a facile one-pot hydrothermal process.The as-fabricated asymmetric hybrid capacitor based on hierarchical MoS2/Ni3S2 electrode exhibit a specific capacitance of^1.033 C/cm2 at1 mA/cm2.Furthermore,the hybrid capacitor unveils an energy density of 35.93 m W h/cm3 at a power density of 1064.76 mW/cm3.The observed results clearly revealed that the synthesized MoS2/Ni3S2 structure might be used as potential electrode material for future energy storage devices.展开更多
NH_(3) plays an essential role in human life since it is an important raw material for fertilizers,plastics and rubbers production.As an NH_(3) synthesis technology under ambient conditions,electrocatalytic N_(2) redu...NH_(3) plays an essential role in human life since it is an important raw material for fertilizers,plastics and rubbers production.As an NH_(3) synthesis technology under ambient conditions,electrocatalytic N_(2) reduction reaction(NRR)has great potential to replace the energy-intensive Haber-Bosch process.The key of electrocatalytic NRR is the exploration of efficient catalysts.Transition metal Mo is promising since it exists naturally in nitrogenase due to the unique Mo-N_(2) interaction;particularly in the form of 2D material such as MoSe_(2),the surface area is maximized for more active sites.However,the NRR performance of MoSe_(2) is still unsatisfactory because Mo is only exposed at the semi-open edge,and the electronegative Se-mantled surface area remains inaccessible to N_(2).Herein,we propose a simple and effective strategy to create high-concentration Se vacancies in MoSe_(2) through heteroatom doping induced lattice strain,which effectively enhances the Mo-N_(2) interaction on the surface area.In result,high NH_(3) yield(3.04×10^(–10)mol s^(–1)cm^(–2))and Faraday efficiency(21.61%)are attained at–0.45 V vs.RHE in 0.1 mol/L Na_(2)SO_(4).展开更多
基金supported by the National Natural Science Foundation of China(No.52302174)the Scientific Research Fund of Hunan Provincial Education Department(Nos.22B0726 and 22B0715)the Ultra-Multi-Wavelength LED Sources(UMW-60)of Qingdao Solar Scientific Instrument High-tech Co.,LTD.
文摘Two-dimensional(2D)materials have been widely used in optoelectronic detection due to their excellent physical properties.Nevertheless,there has been comparatively little focus on the differentiation of light-matter interactions across distinct channel paths within the same 2D material,as well as on the photoelectric characteristics exhibited by the surface,vertical,and bottom of device.In this paper,dual-parallel device structures utilizing 2Dα-In_(2)Se_(3) semiconductors are fabricated with four conductive channels named by bottom-horizontal channel(BHC),middle-vertical channel(MVC),surface-quasi-horizontal channel(SQHC),and surface-horizontal channel(SHC)devices.The SHC device exhibits superior optical response of 101 A/W and external quantum efficiency of 1.857×104%across all conductive channels,which is over 32 times greater than that of BHC device.The SHC device boasts a fast response time of 41 ms,comparable to 32 ms offered by the nanoscale channel of the MVC device,and has a slow decay time of 319 ms similar to the 424 ms that comes with the longest channel of the SQHC device.The SHC device has the highest degree of learning and the lowest forgetting rate compared to the other three channels.Optoelectronic synapses based on dual-parallelα-In_(2)Se_(3) device can also mimic biological color image perception and memory functions,which can be used to visually determine the synaptic function of the device.In this work,on top of the excellent optoelectronic and semiconducting properties of the van der Waals semiconductorα-In2Se3,the advantages offered by the device structure are further explored to promote the development of integrated optoelectronics.
基金Project supported in part by the Science and Technology Development Plan Project of Jilin Province, China (Grant No. YDZJ202303CGZH022)the National Key Research and Development Program of China (Grant No. 2024YFE0205300)+1 种基金the National Natural Science Foundation of China (Grant No. 62471504)the Open Fund of the State Key Laboratory of Optoelectronic Materials and Technologies (Sun Yat-Sen University) (Grant No. OEMT-2023KF-05)。
文摘Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.
基金The work was supported by the National Natural Science Foundation of China(Nos.22175060 and 21975067)Natural Science Foundation of Hunan Province of China(Nos.2021JJ10014 and 2021JJ30092)+1 种基金X.X.X thanks to the National Science Foundation of China(No.12104385)The computational resources were provided by the supercomputer TianHe in Changsha,China.
文摘The layer-dependent properties are still unclarified in two-dimensional(2D)vertical heterostructures.In this study,we layer-bylayer deposited semimetalβ-In2Se3 on monolayer MoS2 to form verticalβ-In2Se3/MoS2 heterostructures by chemical vapor deposition.The defect-mediated nucleation mechanism inducesβ-In2Se3 nanosheets to grow on monolayer MoS2,and the layer number of stackedβ-In2Se3 can be precisely regulated from 1 layer(L)to 13 L by prolonging the growth time.Theβ-In2Se3/MoS2 heterostructures reveal tunable type-Ⅱband alignment arrangement by altering the layer number ofβ-In2Se3,which optimizes the internal electron transfer.Meanwhile,the edge atomic structure ofβ-In2Se3 stacking on monolayer MoS2 shows the reconstruction derived from large lattice mismatch(~29%),and the presence ofβ-In2Se3 also further increases the electrical conductivity ofβ-In2Se3/MoS2 heterostructures.Attributed to abundant layer-dependent edge active sites,edge reconstruction,improved hydrophilicity,and high electrical conductivity ofβ-In2Se3/MoS2 heterostructures,the edge ofβ-In2Se3/MoS2 heterostructures exhibits excellent electrocatalytic hydrogen evolution performance.Lower onset potential and smaller Tafel slope can be observed at the edge of monolayer MoS2 coupled with 13-Lβ-In2Se3.Hence,the outstanding conductive layers coupled with edge reconstruction in 2D vertical heterostructures play decisive roles in the optimization of electron energy levels and improvement of layer-dependent catalytic performance.
基金supported by State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(No.KF201807)
文摘Recently,because of excellent electrical conductivities and many active sites,transition metal sulfides have been utilized as efficient electrodes for supercapacitors.Herein,we synthesize hierarchical MoS2/Ni3S2 structures grown on nickel foam by a facile one-pot hydrothermal process.The as-fabricated asymmetric hybrid capacitor based on hierarchical MoS2/Ni3S2 electrode exhibit a specific capacitance of^1.033 C/cm2 at1 mA/cm2.Furthermore,the hybrid capacitor unveils an energy density of 35.93 m W h/cm3 at a power density of 1064.76 mW/cm3.The observed results clearly revealed that the synthesized MoS2/Ni3S2 structure might be used as potential electrode material for future energy storage devices.
基金financially supported by the National Natural Science Foundation of China(No.52173055)the Natural Science Foundation of Shanghai(No.19ZR1401100)+1 种基金the Fundamental Research Funds for the Central UniversitiesDHU Distinguished Young Professor Program(No.LZA2020001)。
文摘NH_(3) plays an essential role in human life since it is an important raw material for fertilizers,plastics and rubbers production.As an NH_(3) synthesis technology under ambient conditions,electrocatalytic N_(2) reduction reaction(NRR)has great potential to replace the energy-intensive Haber-Bosch process.The key of electrocatalytic NRR is the exploration of efficient catalysts.Transition metal Mo is promising since it exists naturally in nitrogenase due to the unique Mo-N_(2) interaction;particularly in the form of 2D material such as MoSe_(2),the surface area is maximized for more active sites.However,the NRR performance of MoSe_(2) is still unsatisfactory because Mo is only exposed at the semi-open edge,and the electronegative Se-mantled surface area remains inaccessible to N_(2).Herein,we propose a simple and effective strategy to create high-concentration Se vacancies in MoSe_(2) through heteroatom doping induced lattice strain,which effectively enhances the Mo-N_(2) interaction on the surface area.In result,high NH_(3) yield(3.04×10^(–10)mol s^(–1)cm^(–2))and Faraday efficiency(21.61%)are attained at–0.45 V vs.RHE in 0.1 mol/L Na_(2)SO_(4).
