4H-SiC single photon counting avalanche photodiodes(SPADs)are prior devices for weak ultraviolet(UV)signal detection with the advantages of small size,low leakage current,high avalanche multiplication gain,and high qu...4H-SiC single photon counting avalanche photodiodes(SPADs)are prior devices for weak ultraviolet(UV)signal detection with the advantages of small size,low leakage current,high avalanche multiplication gain,and high quantum efficiency,which benefit from the large bandgap energy,high carrier drift velocity and excellent physical stability of 4 H-SiC semiconductor material.UV detectors are widely used in many key applications,such as missile plume detection,corona discharge,UV astronomy,and biological and chemical agent detection.In this paper,we will describe basic concepts and review recent results on device design,process development,and basic characterizations of 4 H-SiC avalanche photodiodes.Several promising device structures and uniformity of avalanche multiplication are discussed,which are important for achieving high performance of 4 HSiC UV SPADs.展开更多
Single-photon detectors possess the ultra-high sensitivity, but they cannot directly respond to signal intensity. Conven- tional methods adopt sampling gates with fixed width and count the triggered number of sampling...Single-photon detectors possess the ultra-high sensitivity, but they cannot directly respond to signal intensity. Conven- tional methods adopt sampling gates with fixed width and count the triggered number of sampling gates, which is capable of obtaining photon counting probability to estimate the echo signal intensity. In this paper, we not only count the number of triggered sampling gates, but also record the triggered time position of photon counting pulses. The photon counting probability density distribution is obtained through the statistics of a series of the triggered time positions. Then Minimum Variance Unbiased Estimation (MVUE) method is used to estimate the echo signal intensity. Compared with conventional methods, this method can improve the estimation accuracy of echo signal intensity due to the acquisition of more detected information. Finally, a proof-of-principle laboratory system is established. The estimation accuracy of echo signal intensity is discussed and a high accuracy intensity image is acquired under low-light level environments.展开更多
X-ray charge-coupled-device(CCD) camera working in single photon counting mode is a type of x-ray spectrometer with high-sensitivity and superior signal-to-noise performance. In this study, two single photon countin...X-ray charge-coupled-device(CCD) camera working in single photon counting mode is a type of x-ray spectrometer with high-sensitivity and superior signal-to-noise performance. In this study, two single photon counting CCD cameras with the same mode(model: PI-LCX: 1300) are calibrated with quasi-monochromatic x-rays from radioactive sources and a conventional x-ray tube. The details of the CCD response to x-rays are analyzed by using a computer program of multi-pixel analyzing and event-distinguishing capability. The detection efficiency, energy resolution, fraction of multi-pixel events each as a function of x-ray energy, and consistence of two CCD cameras are obtained. The calibrated detection efficiency is consistent with the detection efficiency from Monte Carlo calculations with XOP program. When the multi-pixel event analysis is applied, the CCDs may be used to measure x-rays up to 60 ke V with good energy resolution(E /?E ≈ 100 at60 ke V). The difference in detection efficiency between two CCD cameras is small(5.6% at 5.89 ke V), but the difference in fraction of the single pixel event between them is much larger(25% at 8.04 ke V). The obtained small relative error of detection efficiency(2.4% at 5.89 ke V) makes the high accurate measurement of x-ray yield possible in the laser plasma interaction studies. Based on the discrete calibration results, the calculated detection efficiency with XOP can be used for the whole range of 5 ke V–30 ke V.展开更多
This paper proposes two optimal designs of single photon avalanche diodes(SPADs) minimizing dark count rate(DCR). The first structure is introduced as p^+/pwell/nwell, in which a specific shallow pwell layer is added ...This paper proposes two optimal designs of single photon avalanche diodes(SPADs) minimizing dark count rate(DCR). The first structure is introduced as p^+/pwell/nwell, in which a specific shallow pwell layer is added between p^+and nwell layers to decrease the electric field below a certain threshold. The simulation results show on average 19.7%and 8.5% reduction of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. Moreover, a new structure is introduced as n+/nwell/pwell, in which a specific shallow nwell layer is added between n+and pwell layers to lower the electric field below a certain threshold. The simulation results show on average 29.2% and 5.5% decrement of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. It is shown that in higher excess biases(about 6 volts), the n+/nwell/pwell structure is proper to be integrated as digital silicon photomultiplier(dSiPM) due to low DCR. On the other hand, the p^+/pwell/nwell structure is appropriate to be utilized in dSiPM in high temperatures(above 50?C) due to lower DCR value.展开更多
Planar semiconductor InGaAs/InP single photon avalanche diodes with high responsivity and low dark count rate are preferred single photon detectors in near-infrared communication.However,even with well-designed struct...Planar semiconductor InGaAs/InP single photon avalanche diodes with high responsivity and low dark count rate are preferred single photon detectors in near-infrared communication.However,even with well-designed structures and well-con-trolled operational conditions,the performance of InGaAs/InP SPADs is limited by the inherent characteristics of avalanche pro-cess and the growth quality of InGaAs/InP materials.It is difficult to ensure high detection efficiency while the dark count rate is controlled within a certain range at present.In this paper,we fabricated a device with a thick InGaAs absorption region and an anti-reflection layer.The quantum efficiency of this device reaches 83.2%.We characterized the single-photon performance of the device by a quenching circuit consisting of parallel-balanced InGaAs/InP single photon detectors and single-period sinus-oidal pulse gating.The spike pulse caused by the capacitance effect of the device is eliminated by using the characteristics of parallel balanced common mode signal elimination,and the detection of small avalanche pulse amplitude signal is realized.The maximum detection efficiency is 55.4%with a dark count rate of 43.8 kHz and a noise equivalent power of 6.96×10^(−17 )W/Hz^(1/2) at 247 K.Compared with other reported detectors,this SPAD exhibits higher SPDE and lower noise-equivalent power at a higher cooling temperature.展开更多
We propose a method of improving the performance of InGaAs/InP avalanche photodiodes by using two avalanche photodiodes in series as single photon detectors for 1550-nm wavelength. In this method, the raw single photo...We propose a method of improving the performance of InGaAs/InP avalanche photodiodes by using two avalanche photodiodes in series as single photon detectors for 1550-nm wavelength. In this method, the raw single photon avalanche signals are not attenuated, thus a high signal-to-noise ratio can be obtained compared with the existing results. The performance of the scheme is investigated and the ratio of the dark count rate to the detection efficiency is obtained to be 1.3×10^-4 at 213 K.展开更多
A rigorous theoretical model for Ino.53Gao.47As/InP single photon avalanche diode is utilized to investigate the dependences of single photon quantum efficiency and dark count probability on structure and operation co...A rigorous theoretical model for Ino.53Gao.47As/InP single photon avalanche diode is utilized to investigate the dependences of single photon quantum efficiency and dark count probability on structure and operation condition. In the model, low field impact ionizations in charge and absorption layers are allowed, while avalanche breakdown can occur only in the multiplication layer. The origin of dark counts is discussed and the results indicate that the dominant mechanism that gives rise to dark counts depends on both device structure and operating condition. When the multiplication layer is thicker than a critical thickness or the temperature is higher than a critical value, generation-recombination in the absorption layer is the dominative mechanism; otherwise band-to-band tunneling in the multiplication layer dominates the dark counts. The thicknesses of charge and multiplication layers greatly affect the dark count and the peak single photon quantum efficiency and increasing the multiplication layer width may reduce the dark count probability and increase the peak single photon quantum efficiency. However, when the multiplication layer width exceeds 1 μm, the peak single photon quantum efficiency increases slowly and it is finally saturated at the quantum efficiency of the single photon avalanche diodes.展开更多
We demonstrate a photon counting laser ranging experiment with a four-channel single-photon detector(SPD). The multi-channel SPD improve the counting rate more than 4×10~7 cps, which makes possible for the distan...We demonstrate a photon counting laser ranging experiment with a four-channel single-photon detector(SPD). The multi-channel SPD improve the counting rate more than 4×10~7 cps, which makes possible for the distance measurement performed even in daylight. However, the time-correlated single-photon counting(TCSPC) technique cannot distill the signal easily while the fast moving targets are submersed in the strong background. We propose a dynamic TCSPC method for fast moving targets measurement by varying coincidence window in real time. In the experiment, we prove that targets with velocity of 5 km/s can be detected according to the method, while the echo rate is 20% with the background counts of more than 1.2×10~7 cps.展开更多
基于光时域反射技术(Optical Time Domain Reflectometry, OTDR)的光纤分布式传感器可以实现对整个传感光纤空间可分辨的分布式测量,相比点式传感器具有极大的技术及应用成本优势。而传统的基于模拟探测的OTDR光纤分布式传感器在空间分...基于光时域反射技术(Optical Time Domain Reflectometry, OTDR)的光纤分布式传感器可以实现对整个传感光纤空间可分辨的分布式测量,相比点式传感器具有极大的技术及应用成本优势。而传统的基于模拟探测的OTDR光纤分布式传感器在空间分辨率及动态范围上存在性能瓶颈。基于单光子探测的光子计数OTDR光纤分布式传感系统通过数字化的探测和记录方式,可以突破传统OTDR系统的性能极限。本文对光子计数OTDR系统技术及发展进行了综述,旨在通过本文的综述,明确基于单光子探测的光子计数OTDR系统的优势及限制,以及该技术的未来发展趋势,促进基于OTDR技术的光纤分布式传感器的进一步发展。展开更多
Organic-inorganic halide perovskite single crystals(SCs)are promising materials for detecting ionizing radiation owing to their outstanding photoelectric conversion capability and inexpensive solution processability.H...Organic-inorganic halide perovskite single crystals(SCs)are promising materials for detecting ionizing radiation owing to their outstanding photoelectric conversion capability and inexpensive solution processability.However,the accuracy and stability of the detectors have been limited due to the charge traps and defects in SCs,especially when operated under high-precision photon-counting mode for energy spectrum acquisition.Here,we proposed a trap freezing deactivation route,which obviously suppressed dark current and noise by up to 97%and 92%,respectively.Furthermore,the bulk ion migration effect was essential for the ability to instantly self-heal defects induced by radiation damage at temperatures down to30C.Consequently,the detector exhibits a record high energy resolution of 7.5%at 59.5 keV for 241Amγ-ray source,which is the best solution-processed semiconductor radiation detectors at the same energy range.In addition,the detector maintains over 90%of its initial performance after 9 months of storage when tested in the air.Our results will represent a revision of the paradigm that high-spectral-resolution and robust radiation detectors can only be realized with high temperature grown inorganic semiconductor single crystals.展开更多
The first photon bias of photon detection results in distortion of the photon waveform,which seriously affects the accurate acquisition of target information.A rapid universal recursive correction method is proposed,w...The first photon bias of photon detection results in distortion of the photon waveform,which seriously affects the accurate acquisition of target information.A rapid universal recursive correction method is proposed,which is suitable for multi-trigger and single-trigger modes of photon detection.The calculation time is 2 to 3 orders of magnitude faster than that of Xu et al.'s method.In the experiment,we have obtained good correction results for area targets and targets with varying depths.When the average number of echo photons is 0.89,the correlation distance of the correction waveform is reduced by 85%.展开更多
基金supported in part by National Key R&D Program of China under Grant No. 2016YFB0400902in part by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘4H-SiC single photon counting avalanche photodiodes(SPADs)are prior devices for weak ultraviolet(UV)signal detection with the advantages of small size,low leakage current,high avalanche multiplication gain,and high quantum efficiency,which benefit from the large bandgap energy,high carrier drift velocity and excellent physical stability of 4 H-SiC semiconductor material.UV detectors are widely used in many key applications,such as missile plume detection,corona discharge,UV astronomy,and biological and chemical agent detection.In this paper,we will describe basic concepts and review recent results on device design,process development,and basic characterizations of 4 H-SiC avalanche photodiodes.Several promising device structures and uniformity of avalanche multiplication are discussed,which are important for achieving high performance of 4 HSiC UV SPADs.
基金supported by the Fundamental Research Funds for the Central Universities,China(Grant No.AUGA5710056414)the Program for Innovation Research of Science in Harbin Institute of Technology(Grant Nos.PIRS OF HIT A201412 and PIRS OF HIT Q201505)+3 种基金the National Natural Science Foundation of China(Grant No.11675046)the Doctoral Fund of the Ministry of Education of China(Grant No.20122302120003)the Natural Science Foundation of Heilongjiang Province of China(Grant No.A201303)the Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province,China(Grant No.LBH-Q15060)
文摘Single-photon detectors possess the ultra-high sensitivity, but they cannot directly respond to signal intensity. Conven- tional methods adopt sampling gates with fixed width and count the triggered number of sampling gates, which is capable of obtaining photon counting probability to estimate the echo signal intensity. In this paper, we not only count the number of triggered sampling gates, but also record the triggered time position of photon counting pulses. The photon counting probability density distribution is obtained through the statistics of a series of the triggered time positions. Then Minimum Variance Unbiased Estimation (MVUE) method is used to estimate the echo signal intensity. Compared with conventional methods, this method can improve the estimation accuracy of echo signal intensity due to the acquisition of more detected information. Finally, a proof-of-principle laboratory system is established. The estimation accuracy of echo signal intensity is discussed and a high accuracy intensity image is acquired under low-light level environments.
基金Project supported by the Science Foundation of China Academy of Engineering Physics(Grant Nos.2013A0103003 and 2012B0102008)the National High-Tech Inertial Confinement Fusion Committee of China
文摘X-ray charge-coupled-device(CCD) camera working in single photon counting mode is a type of x-ray spectrometer with high-sensitivity and superior signal-to-noise performance. In this study, two single photon counting CCD cameras with the same mode(model: PI-LCX: 1300) are calibrated with quasi-monochromatic x-rays from radioactive sources and a conventional x-ray tube. The details of the CCD response to x-rays are analyzed by using a computer program of multi-pixel analyzing and event-distinguishing capability. The detection efficiency, energy resolution, fraction of multi-pixel events each as a function of x-ray energy, and consistence of two CCD cameras are obtained. The calibrated detection efficiency is consistent with the detection efficiency from Monte Carlo calculations with XOP program. When the multi-pixel event analysis is applied, the CCDs may be used to measure x-rays up to 60 ke V with good energy resolution(E /?E ≈ 100 at60 ke V). The difference in detection efficiency between two CCD cameras is small(5.6% at 5.89 ke V), but the difference in fraction of the single pixel event between them is much larger(25% at 8.04 ke V). The obtained small relative error of detection efficiency(2.4% at 5.89 ke V) makes the high accurate measurement of x-ray yield possible in the laser plasma interaction studies. Based on the discrete calibration results, the calculated detection efficiency with XOP can be used for the whole range of 5 ke V–30 ke V.
文摘This paper proposes two optimal designs of single photon avalanche diodes(SPADs) minimizing dark count rate(DCR). The first structure is introduced as p^+/pwell/nwell, in which a specific shallow pwell layer is added between p^+and nwell layers to decrease the electric field below a certain threshold. The simulation results show on average 19.7%and 8.5% reduction of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. Moreover, a new structure is introduced as n+/nwell/pwell, in which a specific shallow nwell layer is added between n+and pwell layers to lower the electric field below a certain threshold. The simulation results show on average 29.2% and 5.5% decrement of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. It is shown that in higher excess biases(about 6 volts), the n+/nwell/pwell structure is proper to be integrated as digital silicon photomultiplier(dSiPM) due to low DCR. On the other hand, the p^+/pwell/nwell structure is appropriate to be utilized in dSiPM in high temperatures(above 50?C) due to lower DCR value.
基金jointly supported by the National Key Research and Development Program of China (2019YFB22-05202)National Natural Science Foundation of China(61774152)
文摘Planar semiconductor InGaAs/InP single photon avalanche diodes with high responsivity and low dark count rate are preferred single photon detectors in near-infrared communication.However,even with well-designed structures and well-con-trolled operational conditions,the performance of InGaAs/InP SPADs is limited by the inherent characteristics of avalanche pro-cess and the growth quality of InGaAs/InP materials.It is difficult to ensure high detection efficiency while the dark count rate is controlled within a certain range at present.In this paper,we fabricated a device with a thick InGaAs absorption region and an anti-reflection layer.The quantum efficiency of this device reaches 83.2%.We characterized the single-photon performance of the device by a quenching circuit consisting of parallel-balanced InGaAs/InP single photon detectors and single-period sinus-oidal pulse gating.The spike pulse caused by the capacitance effect of the device is eliminated by using the characteristics of parallel balanced common mode signal elimination,and the detection of small avalanche pulse amplitude signal is realized.The maximum detection efficiency is 55.4%with a dark count rate of 43.8 kHz and a noise equivalent power of 6.96×10^(−17 )W/Hz^(1/2) at 247 K.Compared with other reported detectors,this SPAD exhibits higher SPDE and lower noise-equivalent power at a higher cooling temperature.
基金Project supported by the National Major Fundamental Research Program of China(Grant No.2006CB921900)the Knowledge Innovation Project of the Chinese Academy of Sciences,and the National Natural Science Foundation of China(Grant Nos.60537020 and 60121503)
文摘We propose a method of improving the performance of InGaAs/InP avalanche photodiodes by using two avalanche photodiodes in series as single photon detectors for 1550-nm wavelength. In this method, the raw single photon avalanche signals are not attenuated, thus a high signal-to-noise ratio can be obtained compared with the existing results. The performance of the scheme is investigated and the ratio of the dark count rate to the detection efficiency is obtained to be 1.3×10^-4 at 213 K.
基金supported by the National Basic Research Program of China (Grant Nos. G2001039302 and 007CB307001)the Guangdong Provincial Key Technology Research and Development Program,China (Grant No. 2007B010400009)
文摘A rigorous theoretical model for Ino.53Gao.47As/InP single photon avalanche diode is utilized to investigate the dependences of single photon quantum efficiency and dark count probability on structure and operation condition. In the model, low field impact ionizations in charge and absorption layers are allowed, while avalanche breakdown can occur only in the multiplication layer. The origin of dark counts is discussed and the results indicate that the dominant mechanism that gives rise to dark counts depends on both device structure and operating condition. When the multiplication layer is thicker than a critical thickness or the temperature is higher than a critical value, generation-recombination in the absorption layer is the dominative mechanism; otherwise band-to-band tunneling in the multiplication layer dominates the dark counts. The thicknesses of charge and multiplication layers greatly affect the dark count and the peak single photon quantum efficiency and increasing the multiplication layer width may reduce the dark count probability and increase the peak single photon quantum efficiency. However, when the multiplication layer width exceeds 1 μm, the peak single photon quantum efficiency increases slowly and it is finally saturated at the quantum efficiency of the single photon avalanche diodes.
基金supported by the National Natural Science Foundation of China(No.11374105)
文摘We demonstrate a photon counting laser ranging experiment with a four-channel single-photon detector(SPD). The multi-channel SPD improve the counting rate more than 4×10~7 cps, which makes possible for the distance measurement performed even in daylight. However, the time-correlated single-photon counting(TCSPC) technique cannot distill the signal easily while the fast moving targets are submersed in the strong background. We propose a dynamic TCSPC method for fast moving targets measurement by varying coincidence window in real time. In the experiment, we prove that targets with velocity of 5 km/s can be detected according to the method, while the echo rate is 20% with the background counts of more than 1.2×10~7 cps.
基金Supported by the National Natural Science Foundation of China(NSFC)(62174166,11991063,U2241219)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01,22JC1402902)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB43010200)。
文摘基于光时域反射技术(Optical Time Domain Reflectometry, OTDR)的光纤分布式传感器可以实现对整个传感光纤空间可分辨的分布式测量,相比点式传感器具有极大的技术及应用成本优势。而传统的基于模拟探测的OTDR光纤分布式传感器在空间分辨率及动态范围上存在性能瓶颈。基于单光子探测的光子计数OTDR光纤分布式传感系统通过数字化的探测和记录方式,可以突破传统OTDR系统的性能极限。本文对光子计数OTDR系统技术及发展进行了综述,旨在通过本文的综述,明确基于单光子探测的光子计数OTDR系统的优势及限制,以及该技术的未来发展趋势,促进基于OTDR技术的光纤分布式传感器的进一步发展。
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LR22F040003)the National Natural Science Foundation of China(No.62075191,No.52003235,No.22179050,No.21875089,and No.61721005)+3 种基金China Postdoctoral Science Foundation(2022T150251)the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SZ-FR003)the Fundamental Research Funds for the Central Universities(226-2022-00200)Zhejiang University K.P.Chao's High Technology Development Foundation(2022RC008).
文摘Organic-inorganic halide perovskite single crystals(SCs)are promising materials for detecting ionizing radiation owing to their outstanding photoelectric conversion capability and inexpensive solution processability.However,the accuracy and stability of the detectors have been limited due to the charge traps and defects in SCs,especially when operated under high-precision photon-counting mode for energy spectrum acquisition.Here,we proposed a trap freezing deactivation route,which obviously suppressed dark current and noise by up to 97%and 92%,respectively.Furthermore,the bulk ion migration effect was essential for the ability to instantly self-heal defects induced by radiation damage at temperatures down to30C.Consequently,the detector exhibits a record high energy resolution of 7.5%at 59.5 keV for 241Amγ-ray source,which is the best solution-processed semiconductor radiation detectors at the same energy range.In addition,the detector maintains over 90%of its initial performance after 9 months of storage when tested in the air.Our results will represent a revision of the paradigm that high-spectral-resolution and robust radiation detectors can only be realized with high temperature grown inorganic semiconductor single crystals.
基金the National Natural Science Foundation of China(No.61871389)the Research Plan Project of the National University ofDefense Technology(No.ZK 18-01-02)。
文摘The first photon bias of photon detection results in distortion of the photon waveform,which seriously affects the accurate acquisition of target information.A rapid universal recursive correction method is proposed,which is suitable for multi-trigger and single-trigger modes of photon detection.The calculation time is 2 to 3 orders of magnitude faster than that of Xu et al.'s method.In the experiment,we have obtained good correction results for area targets and targets with varying depths.When the average number of echo photons is 0.89,the correlation distance of the correction waveform is reduced by 85%.