Standard GaAs/AlGaAs quantum well infrared photodetectors(QWIP)have been seriously considered as atechnological choice for the 3^(rd) generation of thermal imagers in the long wave infrared band(LWIR)for some time.Alt...Standard GaAs/AlGaAs quantum well infrared photodetectors(QWIP)have been seriously considered as atechnological choice for the 3^(rd) generation of thermal imagers in the long wave infrared band(LWIR)for some time.Alternative technology like MCT(HgCdTe)was the technology choice of the 2^(nd) generation because of its high quantum efficiency.In the paper,measurements on the QWIP technology will be presented and a comparison with alternative technology will be done.展开更多
A new Dark Current Suppression (DCS) CMOS readout circuits for large format Quantum-Well-Infrared Photo-detector (QWIP) Focal-Plane-Array (FPA) with novel Correlated-Double-Sampling (CDS) structure based on dynamic so...A new Dark Current Suppression (DCS) CMOS readout circuits for large format Quantum-Well-Infrared Photo-detector (QWIP) Focal-Plane-Array (FPA) with novel Correlated-Double-Sampling (CDS) structure based on dynamic source-follower are proposed, which can overcome the drawbacks of the present techniques, such as sensitive to the non-uniformity of the QWIP materials, poor readout noise features, low frame frequency, limited injection efficiency and dynamic range, etc. The dummy is adopted to realize dark current suppression, while the cascode current mirror (with current ratio of 1:10) can increase charge sensitivity and reduce integration time. Through the novel CDS structure, the output waveform is boxcar, and the frame frequency is increased. Simulation results demonstrate that, in high background sense, the proposed DCS circuit can suppress the dark current, achieve good readout performance, such as low power consumption, high charge sensitivity, high resolution, large dynamic range, and insensitive to the non-uniformity of the QWIP materials.展开更多
Quantum well infrared photodetectors(QWIPs) based on intersubband transitions hold significant potential for high bandwidth operation. In this work, we establish a carrier transport optimization model incorporating el...Quantum well infrared photodetectors(QWIPs) based on intersubband transitions hold significant potential for high bandwidth operation. In this work, we establish a carrier transport optimization model incorporating electron injection at the emitter to investigate the carrier dynamics time and impedance spectroscopy in GaAs/AlGaAs QWIPs. Our findings provide novel evidence that the escape time of electrons is the key limiting factor for the 3-dB bandwidth of QWIPs. Moreover, to characterize the impact of carrier dynamics time and non-equilibrium space charge region on impedance, we developed an equivalent circuit model where depletion region resistance and capacitance are employed to describe non-equilibrium space charge region. Using this model, we discovered that under illumination, both net charge accumulation caused by variations in carrier dynamics times within quantum wells and changes in width of non-equilibrium space charge region exert different dominant influences on depletion region capacitance at various doping concentrations.展开更多
The design and measurement of a snap-shot mode cryogenic readout circuit（ROIC） for GaAs/AlGaAs QWIP FPAs was reported.CTIA input circuits with pixei level built-in electronic injection transistors were proposed to t...The design and measurement of a snap-shot mode cryogenic readout circuit（ROIC） for GaAs/AlGaAs QWIP FPAs was reported.CTIA input circuits with pixei level built-in electronic injection transistors were proposed to test the chip before assembly with a detector array.Design optimization techniques for cryogenic and low power are analyzed.An experimental ROIC chip of a 128×128 array was fabricated in 0.35μm CMOS technology.Measurements showed that the ROIC could operate at 77 K with low power dissipation of 35 mW.The chip has a pixel charge capacity of 2.57×10^6 electrons and transimpedance of 1.4×10^7Ω.Measurements showed that the transimpedance non-uniformity was less than 5%with a 10 MHz readout speed and a 3.3 V supply voltage.展开更多
The relative coupling efficiency of two-dimensional （2D） grating based on surface plasmon for very long wavelength quantum well infrared detector is analyzed by using the three-dimensional finite-difference time dom...The relative coupling efficiency of two-dimensional （2D） grating based on surface plasmon for very long wavelength quantum well infrared detector is analyzed by using the three-dimensional finite-difference time domain （3D-FDTD） method algorithm. The relative coupling efficiency with respect to the grating parameters, such as grating pitch, duty ratio, and grating thickness, is analyzed. The calculated results show that the relative coupling efficiency would reach the largest value for the 14.5μm incident infrared light when taking the grating pitch as 4.4 μm, the duty ratio as 0.325, and the grating thickness as 0.07 μm, respectively.展开更多
文摘Standard GaAs/AlGaAs quantum well infrared photodetectors(QWIP)have been seriously considered as atechnological choice for the 3^(rd) generation of thermal imagers in the long wave infrared band(LWIR)for some time.Alternative technology like MCT(HgCdTe)was the technology choice of the 2^(nd) generation because of its high quantum efficiency.In the paper,measurements on the QWIP technology will be presented and a comparison with alternative technology will be done.
基金Supported by the National Natural Science Foundation of China(No.60077025)
文摘A new Dark Current Suppression (DCS) CMOS readout circuits for large format Quantum-Well-Infrared Photo-detector (QWIP) Focal-Plane-Array (FPA) with novel Correlated-Double-Sampling (CDS) structure based on dynamic source-follower are proposed, which can overcome the drawbacks of the present techniques, such as sensitive to the non-uniformity of the QWIP materials, poor readout noise features, low frame frequency, limited injection efficiency and dynamic range, etc. The dummy is adopted to realize dark current suppression, while the cascode current mirror (with current ratio of 1:10) can increase charge sensitivity and reduce integration time. Through the novel CDS structure, the output waveform is boxcar, and the frame frequency is increased. Simulation results demonstrate that, in high background sense, the proposed DCS circuit can suppress the dark current, achieve good readout performance, such as low power consumption, high charge sensitivity, high resolution, large dynamic range, and insensitive to the non-uniformity of the QWIP materials.
基金financially supported by the National Natural Science Foundation of China (Grant No. 61991442)。
文摘Quantum well infrared photodetectors(QWIPs) based on intersubband transitions hold significant potential for high bandwidth operation. In this work, we establish a carrier transport optimization model incorporating electron injection at the emitter to investigate the carrier dynamics time and impedance spectroscopy in GaAs/AlGaAs QWIPs. Our findings provide novel evidence that the escape time of electrons is the key limiting factor for the 3-dB bandwidth of QWIPs. Moreover, to characterize the impact of carrier dynamics time and non-equilibrium space charge region on impedance, we developed an equivalent circuit model where depletion region resistance and capacitance are employed to describe non-equilibrium space charge region. Using this model, we discovered that under illumination, both net charge accumulation caused by variations in carrier dynamics times within quantum wells and changes in width of non-equilibrium space charge region exert different dominant influences on depletion region capacitance at various doping concentrations.
文摘The design and measurement of a snap-shot mode cryogenic readout circuit（ROIC） for GaAs/AlGaAs QWIP FPAs was reported.CTIA input circuits with pixei level built-in electronic injection transistors were proposed to test the chip before assembly with a detector array.Design optimization techniques for cryogenic and low power are analyzed.An experimental ROIC chip of a 128×128 array was fabricated in 0.35μm CMOS technology.Measurements showed that the ROIC could operate at 77 K with low power dissipation of 35 mW.The chip has a pixel charge capacity of 2.57×10^6 electrons and transimpedance of 1.4×10^7Ω.Measurements showed that the transimpedance non-uniformity was less than 5%with a 10 MHz readout speed and a 3.3 V supply voltage.
基金Acknowledgement This work was supported by the National Natural Science Foundation of China under Grant No. U1304608, the Outstanding Youth Funding of Henan Polytechnic University under Grant No. J2013-05, and Program for Innovative Research Team of Henan Polytechnic University under Grant No. T2015-3.
文摘The relative coupling efficiency of two-dimensional （2D） grating based on surface plasmon for very long wavelength quantum well infrared detector is analyzed by using the three-dimensional finite-difference time domain （3D-FDTD） method algorithm. The relative coupling efficiency with respect to the grating parameters, such as grating pitch, duty ratio, and grating thickness, is analyzed. The calculated results show that the relative coupling efficiency would reach the largest value for the 14.5μm incident infrared light when taking the grating pitch as 4.4 μm, the duty ratio as 0.325, and the grating thickness as 0.07 μm, respectively.
