The high-temperature performance of 4H-SiC ultraviolet avalanche photodiodes(APDs)in both linear and Geiger modes is extensively investigated.During the temperature-dependent measurements,a fixed bias voltage is adopt...The high-temperature performance of 4H-SiC ultraviolet avalanche photodiodes(APDs)in both linear and Geiger modes is extensively investigated.During the temperature-dependent measurements,a fixed bias voltage is adopted for the device samples,which is much more practical and important for high-temperature applications.The results show that the fabricated 4H-SiC APDs are very stable and reliable at high temperatures.As the temperature increases from room temperature to 425 K,the dark current at 95%of the breakdown voltage increases slightly and remains lower than40 pA.In Geiger mode,our 4H-SiC APDs can be self-quenched in a passive-quenching circuit,which is expected for highspeed detection systems.Moreover,an interesting phenomenon is observed for the first time:the single-photon detection efficiency shows a non-monotonic variation as a function of temperature.The physical mechanism of the variation in hightemperature performance is further analyzed.The results in this work can provide a fundamental reference for researchers in the field of 4H-SiC APD ultraviolet detectors.展开更多
This paper describes a guardring-free planar InAlAs/InGaAs avalanche photodiode(APD)by computational simulations and experimental results.The APD adopts the structure of separate absorption,charge,and multiplication(S...This paper describes a guardring-free planar InAlAs/InGaAs avalanche photodiode(APD)by computational simulations and experimental results.The APD adopts the structure of separate absorption,charge,and multiplication(SACM)with top-illuminated.Computational simulations demonstrate how edge breakdown effect is suppressed in the guardringfree structure.The fabricated APD experiment results show that it can obtain a very low dark current while achieving a high gain×bandwidth(GB)product.The dark current is 3 nA at 0.9Vb r,and the unit responsivity is 0.4 A/W.The maximum3 dB bandwidth of 24 GHz and a GB product of 360 GHz are achieved for the fabricated APD operating at 1.55μm.展开更多
A Ga_(2)O_(3)/diamond separate absorption and multiplication avalanche photodiode(SAM-APD)with mesa structure has been proposed and simulated.The simulation is based on an optimized Ga_(2)O_(3)/diamond heterostructure...A Ga_(2)O_(3)/diamond separate absorption and multiplication avalanche photodiode(SAM-APD)with mesa structure has been proposed and simulated.The simulation is based on an optimized Ga_(2)O_(3)/diamond heterostructure TCAD physical model,which is revised by repeated comparison with the experimental data from the literature.Since both Ga_(2)O_(3)and diamond are ultra-wide bandgap semiconductor materials,the Ga_(2)O_(3)/diamond SAM-APD shows good solar-blind detection ability,and the corresponding cutoff wavelength is about 263 nm.The doping distribution and the electric field distribution of the SAM-APD are discussed,and the simulation results show that the gain of the designed device can reach 5×10^(4)and the peak responsivity can reach a value as high as 78 A/W.展开更多
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
The effect of high-energy proton irradiation on GaN-based ultraviolet avalanche photodiodes(APDs) is investigated. The dark current of the GaN APD is calculated as a function of the proton energy and proton fluences. ...The effect of high-energy proton irradiation on GaN-based ultraviolet avalanche photodiodes(APDs) is investigated. The dark current of the GaN APD is calculated as a function of the proton energy and proton fluences. By considering the diffusion, generation–recombination, local hopping conductivity, band-to-band tunneling, and trap-assisted tunneling currents, we found that the dark current increases as the proton fluence increases, but decreases with increasing proton energy.展开更多
Silicon photonics technology has drawn significant interest due to its potential for compact and high-performance photonic integrated circuits.The Ge-or III-V material-based avalanche photodiodes integrated on silicon...Silicon photonics technology has drawn significant interest due to its potential for compact and high-performance photonic integrated circuits.The Ge-or III-V material-based avalanche photodiodes integrated on silicon photonics provide ideal high sensitivity optical receivers for telecommunication wavelengths.Herein,the last advances of monolithic and hetero-geneous avalanche photodiodes on silicon are reviewed,including different device structures and semiconductor systems.展开更多
We demonstrate two short-wavelength infrared avalanche photodiodes based on InAs/GaSb superlattice grown by metal-organic chemical vapor deposition.The difference between the two devices,namely,p+n-n+and p+nn-n+,is th...We demonstrate two short-wavelength infrared avalanche photodiodes based on InAs/GaSb superlattice grown by metal-organic chemical vapor deposition.The difference between the two devices,namely,p+n-n+and p+nn-n+,is that the p+nn-n+device possesses an additional middle-doped layer to separate the multiplication region from the absorption region.By properly controlling the electric field distribution in the p+nn-n+device,an electric field of 906 kV/cm has been achieved,which is 2.6 times higher than that in the p+n-n+device.At a reverse bias of-0.1 V at 77 K,both devices show a 100%cut-off wavelength of 2.25μm.The p+n-n+and p+nn-n+show a dark current density of 1.5×10^-7 A/cm^2 and 1.8×10^-8 A/cm^2,and a peak responsivity about 0.35 A/W and 0.40 A/W at 1.5μm,respectively.A maximum multiplication gain of 55 is achieved in the p+nn-n+device while the value is only less than 2 in the p+n-n+device.Exponential nature of the gain characteristic as a function of reverse bias confirms a single carrier hole dominated impact ionization.展开更多
Four 4H-SiCp-i-n ultraviolet(UV) avalanche photodiode(APD) samples PIN-0.1, PIN-0.35, PIN-0.5, and PIN-1.0 with different intrinsic layer thicknesses(0.1 μm, 0.35 μm, 0.5 μm, and 1.0 μm, respectively) are designed...Four 4H-SiCp-i-n ultraviolet(UV) avalanche photodiode(APD) samples PIN-0.1, PIN-0.35, PIN-0.5, and PIN-1.0 with different intrinsic layer thicknesses(0.1 μm, 0.35 μm, 0.5 μm, and 1.0 μm, respectively) are designed and fabricated.Single photon detection efficiency(SPDE) performance becomes better as the intrinsic layer thickness increases, which is attributed to the inhibitation of tunneling.Dark count origin is also investigated, an activation energy as small as 0.22 eV of the dark count rate(DCR) confirms that the trap-assisted tunneling(TAT) process is the main source of DCR.The temperature coefficient ranges from-2.6 mV/℃ to 18.3 mV/℃, demonstrating that the TAT process is dominant in APDs with thinner intrinsic layers.Additionally, the room temperature maximum quantum efficiency at 280 nm differs from 48% to 65% for PIN-0.35, PIN-0.5, and PIN-1.0 under 0 V bias, and UV/visible rejection ratios higher than 104 are obtained.展开更多
It is well known that Ⅲ-nitride semiconductors can generate the magnitude of MV/cm polarization electric field which is comparable with their ionization electric fields. To take full advantage of the polarization ele...It is well known that Ⅲ-nitride semiconductors can generate the magnitude of MV/cm polarization electric field which is comparable with their ionization electric fields. To take full advantage of the polarization electric field, we design an N-face AlGaN solar-blind avalanche photodiode(APD) with an Al_(0.45)Ga_(0.55)N/Al_(0.3)Ga_(0.7)N heterostructure as separate absorption and multiplication(SAM) regions. The simulation results show that the N-face APDs are more beneficial to improving the avalanche gain and reducing the avalanche breakdown voltage compared with the Ga-face APDs due to the effect of the polarization electric field. Furthermore, the Al_(0.45)Ga_(0.55)N/Al_(0.3)Ga_(0.7)N heterostructure SAM regions used in APDs instead of homogeneous Al_(0.45)Ga_(0.55)N SAM structure can increase significantly avalanche gain because of the increased hole ionization coefficient by using the relatively low Al-content AlGaN in the multiplication region. Meanwhile, a quarter-wave AlGaN/AIN distributed Bragg reflector structure at the bottom of the device is designed to remain a solar-blind characteristic of the heterostructure SAM-APDs.展开更多
To suppress the electric field crowding at sidewall and improve the detection sensitivity of the AlGaN separate absorption and multiplication(SAM)avalanche photodiodes(APDs),we propose the new AlGaN APDs structure com...To suppress the electric field crowding at sidewall and improve the detection sensitivity of the AlGaN separate absorption and multiplication(SAM)avalanche photodiodes(APDs),we propose the new AlGaN APDs structure combining a large-area mesa with a field plate(FP).The simulated results show that the proposed AlGaN APDs exhibit a significant increase in avalanche gain,about two orders of magnitude,compared to their counterparts without FP structure,which is attributed to the suppression of electric field crowding at sidewall of multiplication layer and the reduction of the maximum electric field at the p-type GaN sidewall in p-n depletion region.Meanwhile,the APDs can produce an obviously enhanced photocurrent due to the increase in cross sectional area of multiplication region.展开更多
We characterized the dependence of the timing jitter of an InGaAs/InP single-photon avalanche diode on the excess bias voltage(V_(ex)) when operated in 1-GHz sinusoidally gated mode.The single-photon avalanche diode w...We characterized the dependence of the timing jitter of an InGaAs/InP single-photon avalanche diode on the excess bias voltage(V_(ex)) when operated in 1-GHz sinusoidally gated mode.The single-photon avalanche diode was cooled to-30 degrees Celsius.When the V_(ex) is too low(0.2 V-0.8 V) or too high(3 V-4.2 V),the timing jitter is increased with the V_(ex),particularly at high V_(ex).While at middle V_(ex)(1 V-2.8 V),the timing jitter is reduced.Measurements of the timing jitter of the same avalanche diode with pulsed gating show that this effect is likely related to the increase of both the amplitude of the V_(ex) and the width of the gate-on time.For the 1-GHz sinusoidally gated detector,the best jitter of 93 ps is achieved with a photon detection efficiency of 21.4%and a dark count rate of ~2.08×10^(-5) per gate at the V_(ex) of 2.8 V.To evaluate the whole performance of the detector,we calculated the noise equivalent power(NEP) and the afterpulse probability(P_(ap)).It is found that both NEP and P_(ap) increase quickly when the V_(ex) is above 2.8 V.At ~2.8-V V_(ex),the NEP and P_(ap) are ~2.06×10^(16)W/Hz^(1/2) and 7.11%,respectively.Therefore,the detector should be operated with V_(ex) of 2.8 V to exploit the fast time response,low NEP and low P_(ap).展开更多
In this study, separate absorption, grading, charge, and multiplication (SAGCM) avalanche photodiode (APD) with double heterojunction AlN/AlxGa1-xN/GaN in multiplication region were designed to reduce excess noise usi...In this study, separate absorption, grading, charge, and multiplication (SAGCM) avalanche photodiode (APD) with double heterojunction AlN/AlxGa1-xN/GaN in multiplication region were designed to reduce excess noise using Monte Carlo simulation. The multiplication region was broken to three different regions and tried to enhance localization of the first and second impact ionization events at near the heterojunctions. The excess noise of the proposed structure, for high gains, was 64% smaller than that of the fabricated standard AlGaN-APDs.展开更多
Avalanche photodiodes(APDs) are promising light sensors with high quantum efficiency and low noise. It has been extensively used in radiation detection,laser radar and other weak signal detection fields. Unlike other ...Avalanche photodiodes(APDs) are promising light sensors with high quantum efficiency and low noise. It has been extensively used in radiation detection,laser radar and other weak signal detection fields. Unlike other photodiodes,APD is a very sensitive light detector with very high internal gain. The basic theory shows that the gain of APD is related to the temperature. The internal gain fluctuates with the variation of temperature. Investigated was the influence of the variation of the gain induced by the fluctuation of temperature on the output from APD for a very weak laser pulse input in laser radar. An active reverse-biased voltage compensation method is used to stabilize the gain of APD. An APD model is setup to simulate the detection of light pulse signal. The avalanche process,various noises and temperature's effect are all included in the model. Our results show that for the detection of weak light signal such as in laser radar,even a very small fluctuation of temperature could cause a great effect on APD's gain. The results show that the signal-to-noise ratio of the APD's output could be improved effectively with the active gain-control system.展开更多
Avalanche photodiodes are widely utilized in research, military and commercial applications which make them attractive for further development. In this paper the results of numerical simulations of uncooled InGaAs/InA...Avalanche photodiodes are widely utilized in research, military and commercial applications which make them attractive for further development. In this paper the results of numerical simulations of uncooled InGaAs/InAlAs/InP based photodiodes are presented. The devices were optimized for 1.55 μm wavelength detection. For device modeling the APSYS Crosslight software was used. Simulated structure consists of separate absorption, charge and multiplication layers with undepleted absorption region and thin charge layer. Based on numerical calculations, the device characteristics like band diagram, dark current, photo current, gain, breakdown voltage and gain bandwidth product were evaluated. The simulation results highlight importance of Zener effect in avalanche photodiode operation.展开更多
基金the National Natural Science Foundation of China(Grant No.61974134)Hebei Province Outstanding Youth Fund(Grant No.F2021516001).
文摘The high-temperature performance of 4H-SiC ultraviolet avalanche photodiodes(APDs)in both linear and Geiger modes is extensively investigated.During the temperature-dependent measurements,a fixed bias voltage is adopted for the device samples,which is much more practical and important for high-temperature applications.The results show that the fabricated 4H-SiC APDs are very stable and reliable at high temperatures.As the temperature increases from room temperature to 425 K,the dark current at 95%of the breakdown voltage increases slightly and remains lower than40 pA.In Geiger mode,our 4H-SiC APDs can be self-quenched in a passive-quenching circuit,which is expected for highspeed detection systems.Moreover,an interesting phenomenon is observed for the first time:the single-photon detection efficiency shows a non-monotonic variation as a function of temperature.The physical mechanism of the variation in hightemperature performance is further analyzed.The results in this work can provide a fundamental reference for researchers in the field of 4H-SiC APD ultraviolet detectors.
基金the National Key R&D Program of China(Grant No.2020YFB1805701)the National Natural Foundation of China(Grant No.61934003)。
文摘This paper describes a guardring-free planar InAlAs/InGaAs avalanche photodiode(APD)by computational simulations and experimental results.The APD adopts the structure of separate absorption,charge,and multiplication(SACM)with top-illuminated.Computational simulations demonstrate how edge breakdown effect is suppressed in the guardringfree structure.The fabricated APD experiment results show that it can obtain a very low dark current while achieving a high gain×bandwidth(GB)product.The dark current is 3 nA at 0.9Vb r,and the unit responsivity is 0.4 A/W.The maximum3 dB bandwidth of 24 GHz and a GB product of 360 GHz are achieved for the fabricated APD operating at 1.55μm.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFB3608602)the Beijing Municipal Science and Technology Commission(Grant No.Z181100004418009)the National Natural Science Foundation of China(Grant No.61927806)。
文摘A Ga_(2)O_(3)/diamond separate absorption and multiplication avalanche photodiode(SAM-APD)with mesa structure has been proposed and simulated.The simulation is based on an optimized Ga_(2)O_(3)/diamond heterostructure TCAD physical model,which is revised by repeated comparison with the experimental data from the literature.Since both Ga_(2)O_(3)and diamond are ultra-wide bandgap semiconductor materials,the Ga_(2)O_(3)/diamond SAM-APD shows good solar-blind detection ability,and the corresponding cutoff wavelength is about 263 nm.The doping distribution and the electric field distribution of the SAM-APD are discussed,and the simulation results show that the gain of the designed device can reach 5×10^(4)and the peak responsivity can reach a value as high as 78 A/W.
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 National Natural Science Foundation of China(No.61404132)the Fundamental Research Funds for the Central Universities(Nos.lzujbky-2015-302,lzujbky-2017-171,and lzujbky-2016-119)
文摘The effect of high-energy proton irradiation on GaN-based ultraviolet avalanche photodiodes(APDs) is investigated. The dark current of the GaN APD is calculated as a function of the proton energy and proton fluences. By considering the diffusion, generation–recombination, local hopping conductivity, band-to-band tunneling, and trap-assisted tunneling currents, we found that the dark current increases as the proton fluence increases, but decreases with increasing proton energy.
文摘Silicon photonics technology has drawn significant interest due to its potential for compact and high-performance photonic integrated circuits.The Ge-or III-V material-based avalanche photodiodes integrated on silicon photonics provide ideal high sensitivity optical receivers for telecommunication wavelengths.Herein,the last advances of monolithic and hetero-geneous avalanche photodiodes on silicon are reviewed,including different device structures and semiconductor systems.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61874179,61804161,and 61975121)the National Key Research and Development Program of China(Grant No.2019YFB2203400).
文摘We demonstrate two short-wavelength infrared avalanche photodiodes based on InAs/GaSb superlattice grown by metal-organic chemical vapor deposition.The difference between the two devices,namely,p+n-n+and p+nn-n+,is that the p+nn-n+device possesses an additional middle-doped layer to separate the multiplication region from the absorption region.By properly controlling the electric field distribution in the p+nn-n+device,an electric field of 906 kV/cm has been achieved,which is 2.6 times higher than that in the p+n-n+device.At a reverse bias of-0.1 V at 77 K,both devices show a 100%cut-off wavelength of 2.25μm.The p+n-n+and p+nn-n+show a dark current density of 1.5×10^-7 A/cm^2 and 1.8×10^-8 A/cm^2,and a peak responsivity about 0.35 A/W and 0.40 A/W at 1.5μm,respectively.A maximum multiplication gain of 55 is achieved in the p+nn-n+device while the value is only less than 2 in the p+n-n+device.Exponential nature of the gain characteristic as a function of reverse bias confirms a single carrier hole dominated impact ionization.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0400902)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Four 4H-SiCp-i-n ultraviolet(UV) avalanche photodiode(APD) samples PIN-0.1, PIN-0.35, PIN-0.5, and PIN-1.0 with different intrinsic layer thicknesses(0.1 μm, 0.35 μm, 0.5 μm, and 1.0 μm, respectively) are designed and fabricated.Single photon detection efficiency(SPDE) performance becomes better as the intrinsic layer thickness increases, which is attributed to the inhibitation of tunneling.Dark count origin is also investigated, an activation energy as small as 0.22 eV of the dark count rate(DCR) confirms that the trap-assisted tunneling(TAT) process is the main source of DCR.The temperature coefficient ranges from-2.6 mV/℃ to 18.3 mV/℃, demonstrating that the TAT process is dominant in APDs with thinner intrinsic layers.Additionally, the room temperature maximum quantum efficiency at 280 nm differs from 48% to 65% for PIN-0.35, PIN-0.5, and PIN-1.0 under 0 V bias, and UV/visible rejection ratios higher than 104 are obtained.
基金Supported by the State Key Project of Research and Development Plan of China under Grant No 2016YFB0400903the National Natural Science Foundation of China under Grant Nos 61634002,61274075 and 61474060+2 种基金the Key Project of Jiangsu Province under Grant No BE2016174the Anhui University Natural Science Research Project under Grant No KJ2015A153the Open Fund of State KeyLab of Optical Technologies on Nano-fabrication and Micro-engineering
文摘It is well known that Ⅲ-nitride semiconductors can generate the magnitude of MV/cm polarization electric field which is comparable with their ionization electric fields. To take full advantage of the polarization electric field, we design an N-face AlGaN solar-blind avalanche photodiode(APD) with an Al_(0.45)Ga_(0.55)N/Al_(0.3)Ga_(0.7)N heterostructure as separate absorption and multiplication(SAM) regions. The simulation results show that the N-face APDs are more beneficial to improving the avalanche gain and reducing the avalanche breakdown voltage compared with the Ga-face APDs due to the effect of the polarization electric field. Furthermore, the Al_(0.45)Ga_(0.55)N/Al_(0.3)Ga_(0.7)N heterostructure SAM regions used in APDs instead of homogeneous Al_(0.45)Ga_(0.55)N SAM structure can increase significantly avalanche gain because of the increased hole ionization coefficient by using the relatively low Al-content AlGaN in the multiplication region. Meanwhile, a quarter-wave AlGaN/AIN distributed Bragg reflector structure at the bottom of the device is designed to remain a solar-blind characteristic of the heterostructure SAM-APDs.
基金the Natural Science Research Project of Anhui University,China(Grant No.KJ2019A0644)the National Natural Science Foundation of China(Grant Nos.61634002 and 61804089)+3 种基金the Natural Science Alliance Foundation,China(Grant No.U1830109)the Natural Science Foundation of Anhui Province,China(Grant No.1708085MF149)the Chuzhou University Research Project,China(Grant No.zrjz2019002)the Project of the Higher Educational and Technology Program of Shandong Province,China(Grant No.J16LN04).
文摘To suppress the electric field crowding at sidewall and improve the detection sensitivity of the AlGaN separate absorption and multiplication(SAM)avalanche photodiodes(APDs),we propose the new AlGaN APDs structure combining a large-area mesa with a field plate(FP).The simulated results show that the proposed AlGaN APDs exhibit a significant increase in avalanche gain,about two orders of magnitude,compared to their counterparts without FP structure,which is attributed to the suppression of electric field crowding at sidewall of multiplication layer and the reduction of the maximum electric field at the p-type GaN sidewall in p-n depletion region.Meanwhile,the APDs can produce an obviously enhanced photocurrent due to the increase in cross sectional area of multiplication region.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11275024,61274024,and 61474123)the Youth Innovation Promotion Association,China(Grant No.2013105)the Ministry of Science and Technology of China(Grant Nos.2013YQ030595-3 and 2011AA120101)
文摘We characterized the dependence of the timing jitter of an InGaAs/InP single-photon avalanche diode on the excess bias voltage(V_(ex)) when operated in 1-GHz sinusoidally gated mode.The single-photon avalanche diode was cooled to-30 degrees Celsius.When the V_(ex) is too low(0.2 V-0.8 V) or too high(3 V-4.2 V),the timing jitter is increased with the V_(ex),particularly at high V_(ex).While at middle V_(ex)(1 V-2.8 V),the timing jitter is reduced.Measurements of the timing jitter of the same avalanche diode with pulsed gating show that this effect is likely related to the increase of both the amplitude of the V_(ex) and the width of the gate-on time.For the 1-GHz sinusoidally gated detector,the best jitter of 93 ps is achieved with a photon detection efficiency of 21.4%and a dark count rate of ~2.08×10^(-5) per gate at the V_(ex) of 2.8 V.To evaluate the whole performance of the detector,we calculated the noise equivalent power(NEP) and the afterpulse probability(P_(ap)).It is found that both NEP and P_(ap) increase quickly when the V_(ex) is above 2.8 V.At ~2.8-V V_(ex),the NEP and P_(ap) are ~2.06×10^(16)W/Hz^(1/2) and 7.11%,respectively.Therefore,the detector should be operated with V_(ex) of 2.8 V to exploit the fast time response,low NEP and low P_(ap).
文摘In this study, separate absorption, grading, charge, and multiplication (SAGCM) avalanche photodiode (APD) with double heterojunction AlN/AlxGa1-xN/GaN in multiplication region were designed to reduce excess noise using Monte Carlo simulation. The multiplication region was broken to three different regions and tried to enhance localization of the first and second impact ionization events at near the heterojunctions. The excess noise of the proposed structure, for high gains, was 64% smaller than that of the fabricated standard AlGaN-APDs.
基金Young Scientist Research Fund of Heilongjiang University(QL200508)
文摘Avalanche photodiodes(APDs) are promising light sensors with high quantum efficiency and low noise. It has been extensively used in radiation detection,laser radar and other weak signal detection fields. Unlike other photodiodes,APD is a very sensitive light detector with very high internal gain. The basic theory shows that the gain of APD is related to the temperature. The internal gain fluctuates with the variation of temperature. Investigated was the influence of the variation of the gain induced by the fluctuation of temperature on the output from APD for a very weak laser pulse input in laser radar. An active reverse-biased voltage compensation method is used to stabilize the gain of APD. An APD model is setup to simulate the detection of light pulse signal. The avalanche process,various noises and temperature's effect are all included in the model. Our results show that for the detection of weak light signal such as in laser radar,even a very small fluctuation of temperature could cause a great effect on APD's gain. The results show that the signal-to-noise ratio of the APD's output could be improved effectively with the active gain-control system.
基金partially supported by The National Centre for Research and Development,Poland under project No N R02 0025 06support from MPNS COST ACTION MP1204-TERA-MIR Radiation:Materials,Generation,Detection and Applications.
文摘Avalanche photodiodes are widely utilized in research, military and commercial applications which make them attractive for further development. In this paper the results of numerical simulations of uncooled InGaAs/InAlAs/InP based photodiodes are presented. The devices were optimized for 1.55 μm wavelength detection. For device modeling the APSYS Crosslight software was used. Simulated structure consists of separate absorption, charge and multiplication layers with undepleted absorption region and thin charge layer. Based on numerical calculations, the device characteristics like band diagram, dark current, photo current, gain, breakdown voltage and gain bandwidth product were evaluated. The simulation results highlight importance of Zener effect in avalanche photodiode operation.