Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by hig...Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by high dark current,which can greatly reduce their performance and sensitivity,thereby limiting their effectiveness in certain applications.In this work,the introduction of a C60 back interface layer successfully mitigated back interface reactions to decrease the thickness of the Mo(S,Se)_(2)layer,tailoring the back-contact barrier and preventing reverse charge injection,resulting in a kesterite photodetector with an ultralow dark current density of 5.2×10^(-9)mA/cm^(2)and ultra-weak-light detection at levels as low as 25 pW/cm^(2).Besides,under a self-powered operation,it demonstrates outstanding performance,achieving a peak responsivity of 0.68 A/W,a wide response range spanning from 300 to 1600 nm,and an impressive detectivity of 5.27×10^(14)Jones.In addition,it offers exceptionally rapid response times,with rise and decay times of 70 and 650 ns,respectively.This research offers important insights for developing high-performance self-powered near-infrared photodetectors that have high responsivity,rapid response times,and ultralow dark current.展开更多
Neutron capture event imaging is a novel technique that has the potential to substantially enhance the resolution of existing imaging systems.This study provides a measurement method for neutron capture event distribu...Neutron capture event imaging is a novel technique that has the potential to substantially enhance the resolution of existing imaging systems.This study provides a measurement method for neutron capture event distribution along with multiple reconstruction methods for super-resolution imaging.The proposed technology reduces the point-spread function of an imag-ing system through single-neutron detection and event reconstruction,thereby significantly improving imaging resolution.A single-neutron detection experiment was conducted using a highly practical and efficient^(6)LiF-ZnS scintillation screen of a cold neutron imaging device in the research reactor.In milliseconds of exposure time,a large number of weak light clusters and their distribution in the scintillation screen were recorded frame by frame,to complete single-neutron detection.Several reconstruction algorithms were proposed for the calculations.The location of neutron capture was calculated using several processing methods such as noise removal,filtering,spot segmentation,contour analysis,and local positioning.The proposed algorithm achieved a higher imaging resolution and faster reconstruction speed,and single-neutron super-resolution imaging was realized by combining single-neutron detection experiments and reconstruction calculations.The results show that the resolution of the 100μm thick^(6)LiF-ZnS scintillation screen can be improved from 125 to 40 microns.This indicates that the proposed single-neutron detection and calculation method is effective and can significantly improve imaging resolution.展开更多
Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is a promising candidate for photodetector(PD)applications thanks to its excellent optoelectronic properties.In this work,a green solution-processed spin coating and selenization-...Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is a promising candidate for photodetector(PD)applications thanks to its excellent optoelectronic properties.In this work,a green solution-processed spin coating and selenization-processed thermodynamic or kinetic growth of high-quality narrow bandgap kesterite CZTSSe thin film is developed.A self-powered CZTSSe/CdS thin-film PD is then successfully fabricated.Under optimization of light absorber and heterojunction interface,especially tailoring the defect and carrier kinetics,it can achieve broadband response from300 to 1300 nm,accompaniedwith a high responsivity of 1.37A/W,specific detectivity(D*)up to 4.0×10^(14)Jones under 5 nW/cm^(2),a linear dynamic range(LDR)of 126 dB,and a maximum Ilight/Idark ratio of 1.3×10^(8)within the LDR,and ultrafast response speed(rise/decay time of 16 ns/85 ns),representing the leading-level performance to date,which is superior to those of commercial andwell-researched photodiodes.Additionally,an imaging system with a 905nm laser is built for weak light response evaluation,and can respond to 718 pW weak light and infrared imaging at a wavelength as low as 5 nW/cm2.It has also been employed for photoplethysmography detection of pulsating signals at both the finger and wrist,presenting obvious arterial blood volume changes,demonstrating great application potential in broadband and weak light photodetection scenarios.展开更多
Due to the outstanding anti-interference capability against the ambient noise,LiDARs based on frequencymodulated continuous wave(FMCW)technology with high sensitivity and high signal-to-noise ratio(SNR)are essential t...Due to the outstanding anti-interference capability against the ambient noise,LiDARs based on frequencymodulated continuous wave(FMCW)technology with high sensitivity and high signal-to-noise ratio(SNR)are essential to achieve ideal photodetection of weak light.To significantly improve the weak light detection performance of balanced photodetectors,this work first demonstrates a novel near-infrared germanium-on-silicon(Ge/Si)avalanche photodetector with a three-electrode balanced scheme.The single three-electrode avalanche photodetector exhibits a high responsivity of>200 A=W near breakdown voltage.The three-electrode balanced avalanche photodetector(3ele-BAPD)achieves a common-mode rejection ratio(CMRR)of 50 dB at an operating wavelength of 1550 nm.We have set up the FMCW coherent detection system.The minimum detectable power of−93 dBm can be achieved,corresponding to an SNR of 3.2 dB and a detection probability of 54%.In comparison,the performance exceeds that of the two-electrode balanced avalanche photodetector(2ele-BAPD),which exhibits a minimum detectable power of−85 dBm with a corresponding SNR of 3.1 dB and a detection probability of 51%.The superior weak light detection performance enables the 3ele-BAPD to accomplish 3D imaging based on the FMCW LiDAR scheme.Moreover,the 3ele-BAPD is also applied to velocity measurement for 4D sensing.The applications of LiDAR velocity measurement and imaging are verified.展开更多
基金supported by the National Natural Science Foundation of China(No.52472225)the Science and Technology Plan Project of Shenzhen(No.20220808165025003),China。
文摘Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by high dark current,which can greatly reduce their performance and sensitivity,thereby limiting their effectiveness in certain applications.In this work,the introduction of a C60 back interface layer successfully mitigated back interface reactions to decrease the thickness of the Mo(S,Se)_(2)layer,tailoring the back-contact barrier and preventing reverse charge injection,resulting in a kesterite photodetector with an ultralow dark current density of 5.2×10^(-9)mA/cm^(2)and ultra-weak-light detection at levels as low as 25 pW/cm^(2).Besides,under a self-powered operation,it demonstrates outstanding performance,achieving a peak responsivity of 0.68 A/W,a wide response range spanning from 300 to 1600 nm,and an impressive detectivity of 5.27×10^(14)Jones.In addition,it offers exceptionally rapid response times,with rise and decay times of 70 and 650 ns,respectively.This research offers important insights for developing high-performance self-powered near-infrared photodetectors that have high responsivity,rapid response times,and ultralow dark current.
基金supported by the National Natural Science Foundation of China(Nos.12205271,12075217,U20B2011,and 51978218)Sichuan Science and Technology Program(No.2019ZDZX0010)the National Key R&D Program of China(No.2022YFA1604002).
文摘Neutron capture event imaging is a novel technique that has the potential to substantially enhance the resolution of existing imaging systems.This study provides a measurement method for neutron capture event distribution along with multiple reconstruction methods for super-resolution imaging.The proposed technology reduces the point-spread function of an imag-ing system through single-neutron detection and event reconstruction,thereby significantly improving imaging resolution.A single-neutron detection experiment was conducted using a highly practical and efficient^(6)LiF-ZnS scintillation screen of a cold neutron imaging device in the research reactor.In milliseconds of exposure time,a large number of weak light clusters and their distribution in the scintillation screen were recorded frame by frame,to complete single-neutron detection.Several reconstruction algorithms were proposed for the calculations.The location of neutron capture was calculated using several processing methods such as noise removal,filtering,spot segmentation,contour analysis,and local positioning.The proposed algorithm achieved a higher imaging resolution and faster reconstruction speed,and single-neutron super-resolution imaging was realized by combining single-neutron detection experiments and reconstruction calculations.The results show that the resolution of the 100μm thick^(6)LiF-ZnS scintillation screen can be improved from 125 to 40 microns.This indicates that the proposed single-neutron detection and calculation method is effective and can significantly improve imaging resolution.
基金National Natural Science Foundation of China,Grant/Award Numbers:62074102,62104156,21961160720Open Research Fund of Songshan Lake Materials Laboratory,Grant/Award Number:2021SLABFK02+1 种基金Guangdong Basic and Applied Basic Research Foundation,Grant/Award Numbers:2022A1515010979,2023A1515011256Science and Technology Plan Project of Shenzhen,Grant/Award。
文摘Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is a promising candidate for photodetector(PD)applications thanks to its excellent optoelectronic properties.In this work,a green solution-processed spin coating and selenization-processed thermodynamic or kinetic growth of high-quality narrow bandgap kesterite CZTSSe thin film is developed.A self-powered CZTSSe/CdS thin-film PD is then successfully fabricated.Under optimization of light absorber and heterojunction interface,especially tailoring the defect and carrier kinetics,it can achieve broadband response from300 to 1300 nm,accompaniedwith a high responsivity of 1.37A/W,specific detectivity(D*)up to 4.0×10^(14)Jones under 5 nW/cm^(2),a linear dynamic range(LDR)of 126 dB,and a maximum Ilight/Idark ratio of 1.3×10^(8)within the LDR,and ultrafast response speed(rise/decay time of 16 ns/85 ns),representing the leading-level performance to date,which is superior to those of commercial andwell-researched photodiodes.Additionally,an imaging system with a 905nm laser is built for weak light response evaluation,and can respond to 718 pW weak light and infrared imaging at a wavelength as low as 5 nW/cm2.It has also been employed for photoplethysmography detection of pulsating signals at both the finger and wrist,presenting obvious arterial blood volume changes,demonstrating great application potential in broadband and weak light photodetection scenarios.
基金supported by the National Natural Science Foundation of China(62074111 and 62374115)the Innovation Program of Shanghai Municipal Education Commission(2021-01-07-00-07-E00096)the National Key Research and Development Program of China(2022YFB3203502)。
文摘有机-无机卤化物钙钛矿因其可溶液加工和优异的光电特性而在光电探测器(PD)中得到了广泛应用.然而,基于钙钛矿的PD一般需要电荷传输层提供足够的分离和传输驱动力,这会增加钙钛矿PD的材料成本.本研究通过溶液法制备了基于苯基三甲基氯化铵(PTACl)处理的无电荷传输层钙钛矿自供电PD.以(CsFAMA)Pb(BrI)3作为光活性层,这种三元阳离子混合卤化物钙钛矿沉积后的垂直分布差异为电荷分离和传输提供了驱动力,PTACl处理能加强电荷分离和运输.这种PD在自供电模式下表现出优异的光电探测性能,其中光暗电流比为1.8×10^(5),响应度为198 mA W^(−1),探测率为1.48×10^(13)/1.24×10^(11) Jones(暗/噪声电流法计算).没有封装的PD在700 h的测试中也表现出良好的空气稳定性,且该PD对0.64 nW cm^(−2)的弱光仍有明显的响应,PD阵列也验证了这种弱光检测能力.本工作制备的钙钛矿自供电PD为弱光检测的发展提供了一种简单可行的途径.
基金National Natural Science Foundation of China(62090054,61934003)National Key Research and Development Program of China(2022YFB2804504)+2 种基金Major Scientific and Technological Program of Jilin Province(20210301014GX)Jilin Provincial Development and Reform Commission Project(2020C056)Program for Jilin University Science and Technology Innovative Research Team(JLUSTIRT,2021TD-39).
文摘Due to the outstanding anti-interference capability against the ambient noise,LiDARs based on frequencymodulated continuous wave(FMCW)technology with high sensitivity and high signal-to-noise ratio(SNR)are essential to achieve ideal photodetection of weak light.To significantly improve the weak light detection performance of balanced photodetectors,this work first demonstrates a novel near-infrared germanium-on-silicon(Ge/Si)avalanche photodetector with a three-electrode balanced scheme.The single three-electrode avalanche photodetector exhibits a high responsivity of>200 A=W near breakdown voltage.The three-electrode balanced avalanche photodetector(3ele-BAPD)achieves a common-mode rejection ratio(CMRR)of 50 dB at an operating wavelength of 1550 nm.We have set up the FMCW coherent detection system.The minimum detectable power of−93 dBm can be achieved,corresponding to an SNR of 3.2 dB and a detection probability of 54%.In comparison,the performance exceeds that of the two-electrode balanced avalanche photodetector(2ele-BAPD),which exhibits a minimum detectable power of−85 dBm with a corresponding SNR of 3.1 dB and a detection probability of 51%.The superior weak light detection performance enables the 3ele-BAPD to accomplish 3D imaging based on the FMCW LiDAR scheme.Moreover,the 3ele-BAPD is also applied to velocity measurement for 4D sensing.The applications of LiDAR velocity measurement and imaging are verified.
