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- 实验方案
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High-performance long-wavelength InAs/GaSb superlattice detectors grown by MOCVD
摘要： We demonstrate high-performance long-wavelength InAs/GaSb superlattice (SL) infrared photodetectors based on an Al-free single heterojunction grown by metalorganic chemical vapor deposition (MOCVD). The device structure consists of a mid-wavelength InAs/GaSb SL p-n junction (PN) and a long-wavelength InAs/GaSb SL n-type absorber (n), so-called PNn design, to reduce the dark current. In addition, a shallow etch technique was employed by exposing only mid-wavelength materials during pixel isolation to suppress surface leakage currents. At 77 K and a bias voltage of -0.1 V, the device exhibited a 50% cut-off wavelength at 8.0 μm, a dark current density of 2.4×10-5 A/cm2, and a peak responsivity of 2.1 A/W. Temperature dependent dark current measurement indicated diffusion-limited behavior down to 75 K. The specific detectivity was estimated to be 7.3×1011 cm·Hz1/2/W, which is comparable with that of detectors grown by molecular beam epitaxy (MBE) at similar cut-off wavelengths.
关键词： InAs/GaSb type-II superlattices,metalorganic chemical vapor deposition,heterostructure,long-wavelength infrared
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE Workshop on Power Electronics and Power Quality Applications (PEPQA) - Manizales, Colombia (2019.5.30-2019.5.31)] 2019 IEEE Workshop on Power Electronics and Power Quality Applications (PEPQA) - Determination and Performance Analysis of the Norton Equivalent Models for Fluorescents and LED Recessed Lightings
摘要： For long-wavelength space-based radars, such as the P-band radar on the recently selected European Space Agency BIOMASS mission, system distortions (crosstalk and channel imbalance), Faraday rotation, and system noise all combine to degrade the measurements. A first-order analysis of these effects on the measurements of the polarimetric scattering matrix is used to derive differentiable expressions for the errors in the polarimetric backscattering coefficients in the presence of Faraday rotation. Both the amplitudes and phases of the distortion terms are shown to be important in determining the errors and their maximum values. Exact simulations confirm the accuracy and predictions of the first-order analysis. Under an assumed power-law relation between σhv and the biomass, the system distortions and noise are converted into biomass estimation errors, and it is shown that the magnitude of the deviation of the channel imbalance from unity must be 4–5 dB less than the crosstalk, or it will dominate the error in the biomass. For uncalibrated data and midrange values of biomass, the crosstalk must be less than ?24 dB if the maximum possible error in the biomass is to be within 20% of its true value. A less stringent condition applies if the amplitudes and phases of the distortion terms are considered random since errors near the maximum possible are very unlikely. For lower values of the biomass, the noise becomes increasingly important because the σhv signal-to-noise ratio is smaller.
关键词： Biomass,Faraday rotation,polarimetric measurements,system distortion,calibration,long-wavelength radar
更新于2025-09-23 15:21:01
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Ultrabroadband Photodetectors up to 10.6 ?μm Based on 2D Fe <sub/>3</sub> O <sub/>4</sub> Nanosheets
摘要： The ultrabroadband spectrum detection from ultraviolet (UV) to long-wavelength infrared (LWIR) is promising for diversified optoelectronic applications of imaging, sensing, and communication. However, the current LWIR-detecting devices suffer from low photoresponsivity, high cost, and cryogenic environment. Herein, a high-performance ultrabroadband photodetector is demonstrated with detecting range from UV to LWIR based on air-stable non-layered ultrathin Fe3O4 nanosheets synthesized via a space-confined chemical vapor deposition (CVD) method. Ultrahigh photoresponsivity (R) of 561.2 A W?1, external quantum efficiency (EQE) of 6.6 × 103%, and detectivity (D*) of 7.42 × 108 Jones are achieved at the wavelength of 10.6 μm. The multi-mechanism synergistic effect of photoconductive effect and bolometric effect demonstrates the high sensitivity for light with any light intensities. The outstanding device performance and complementary mixing photo response mechanisms open up new potential applications of nonlayered 2D materials for future infrared optoelectronic devices.
关键词： long-wavelength infrared,photoconductive effect,ultrabroadband photodetectors,bolometric effect,Fe3O4 nanosheets
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE Transportation Electrification Conference and Expo, Asia-Pacific (ITEC Asia-Pacific) - Seogwipo-si, Korea (South) (2019.5.8-2019.5.10)] 2019 IEEE Transportation Electrification Conference and Expo, Asia-Pacific (ITEC Asia-Pacific) - Optimal scheduling of critical peak pricing considering photovoltaic generation and electric vehicle load
摘要： For long-wavelength space-based radars, such as the P-band radar on the recently selected European Space Agency BIOMASS mission, system distortions (crosstalk and channel imbalance), Faraday rotation, and system noise all combine to degrade the measurements. A first-order analysis of these effects on the measurements of the polarimetric scattering matrix is used to derive differentiable expressions for the errors in the polarimetric backscattering coefficients in the presence of Faraday rotation. Both the amplitudes and phases of the distortion terms are shown to be important in determining the errors and their maximum values. Exact simulations confirm the accuracy and predictions of the first-order analysis. Under an assumed power-law relation between σhv and the biomass, the system distortions and noise are converted into biomass estimation errors, and it is shown that the magnitude of the deviation of the channel imbalance from unity must be 4–5 dB less than the crosstalk, or it will dominate the error in the biomass. For uncalibrated data and midrange values of biomass, the crosstalk must be less than ?24 dB if the maximum possible error in the biomass is to be within 20% of its true value. A less stringent condition applies if the amplitudes and phases of the distortion terms are considered random since errors near the maximum possible are very unlikely. For lower values of the biomass, the noise becomes increasingly important because the σhv signal-to-noise ratio is smaller.
关键词： Biomass,Faraday rotation,polarimetric measurements,system distortion,calibration,long-wavelength radar
更新于2025-09-23 15:19:57
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Modal Analysis of 2-D Material-based Plasmonic Waveguides by Mixed Spectral Element Method with Equivalent Boundary Condition
摘要： For long-wavelength space-based radars, such as the P-band radar on the recently selected European Space Agency BIOMASS mission, system distortions (crosstalk and channel imbalance), Faraday rotation, and system noise all combine to degrade the measurements. A first-order analysis of these effects on the measurements of the polarimetric scattering matrix is used to derive differentiable expressions for the errors in the polarimetric backscattering coefficients in the presence of Faraday rotation. Both the amplitudes and phases of the distortion terms are shown to be important in determining the errors and their maximum values. Exact simulations confirm the accuracy and predictions of the first-order analysis. Under an assumed power-law relation between σhv and the biomass, the system distortions and noise are converted into biomass estimation errors, and it is shown that the magnitude of the deviation of the channel imbalance from unity must be 4–5 dB less than the crosstalk, or it will dominate the error in the biomass. For uncalibrated data and midrange values of biomass, the crosstalk must be less than ?24 dB if the maximum possible error in the biomass is to be within 20% of its true value. A less stringent condition applies if the amplitudes and phases of the distortion terms are considered random since errors near the maximum possible are very unlikely. For lower values of the biomass, the noise becomes increasingly important because the σhv signal-to-noise ratio is smaller.
关键词： Biomass,Faraday rotation,polarimetric measurements,system distortion,calibration,long-wavelength radar
更新于2025-09-23 15:19:57
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A long-wavelength-emitting fluorescent probe for simultaneous discrimination of H2S/Cys/GSH and its bio-imaging applications
摘要： A long-wavelength fluorescent probe NR-CY was developed for simultaneous identification of cysteine / glutathione and sulphide by combining the derivative of Nile red with 7-nitrobenzofurazan. The response of NR-CY to thiols is regulated by intramolecular charge transfer and photoinduced electron transfer mechanisms. For sulphide at 560 nm, cysteine at 475 nm and glutathione at 425 nm, different absorbance increases can be observed. NR-CY can detect cysteine at fluorescence emission 543 nm and distinguish sulphide from other analytes by kinetic experiments at 636 nm. The probe showed a rapid response to these thiols (cysteine was 90 s and sulphide was 30 s). In addition, NR-CY has been successfully applied to live MCF-7 cell imaging.
关键词： biothiols,Fluorescent probe,cell imaging,long-wavelength-emitting
更新于2025-09-23 15:19:57
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Carrier reduction studies of type-II superlattice materials for very long wavelength infrared sensing
摘要： There are continuing efforts to develop type-II superlattice (SL) materials for very long wavelength infrared (VLWIR) detector applications. However, the SLs have high residual electron background doping densities that depend on SL growth conditions, which lead to shorter minority carrier lifetime and lower performance parameters than theoretically predicted. In this study, the authors compare the technical advantages of using InAs/GaInSb over InAs/GaSb SL with respect to reducing the electron doping levels. Our temperature-dependent electrical transport measurements show that the InAs/GaInSb SL design has a lower electron density than the InAs/GaSb SL with the same bandgap and have electron densities (mobilities) on the order of the mid 1011 cm?2 (25 000 cm2/V s). Since small period InAs/GaInSb SLs also produce greater Auger recombination suppression for a given VLWIR gap than the large period InAs/GaSb SL, the InAs/GaInSb SL appears to be a better candidate for long lifetime IR materials for future very long wavelength infrared devices.
关键词： very long wavelength infrared,mobility,InAs/GaSb,Auger recombination,InAs/GaInSb,type-II superlattice,carrier reduction,electron doping
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Epitaxial GaP grown on Silicon by MEE and MBE Techniques as a Pathway for Dilute Nitride-Si Tandem Solar Cells
摘要： For long-wavelength space-based radars, such as the P-band radar on the recently selected European Space Agency BIOMASS mission, system distortions (crosstalk and channel imbalance), Faraday rotation, and system noise all combine to degrade the measurements. A first-order analysis of these effects on the measurements of the polarimetric scattering matrix is used to derive differentiable expressions for the errors in the polarimetric backscattering coefficients in the presence of Faraday rotation. Both the amplitudes and phases of the distortion terms are shown to be important in determining the errors and their maximum values. Exact simulations confirm the accuracy and predictions of the first-order analysis. Under an assumed power-law relation between σhv and the biomass, the system distortions and noise are converted into biomass estimation errors, and it is shown that the magnitude of the deviation of the channel imbalance from unity must be 4–5 dB less than the crosstalk, or it will dominate the error in the biomass. For uncalibrated data and midrange values of biomass, the crosstalk must be less than ?24 dB if the maximum possible error in the biomass is to be within 20% of its true value. A less stringent condition applies if the amplitudes and phases of the distortion terms are considered random since errors near the maximum possible are very unlikely. For lower values of the biomass, the noise becomes increasingly important because the σhv signal-to-noise ratio is smaller.
关键词： Biomass,Faraday rotation,polarimetric measurements,system distortion,calibration,long-wavelength radar
更新于2025-09-19 17:13:59
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Long wavelength type II InAs/GaSb superlattice photodetector using resonant tunneling diode structure
摘要： We report on a long wavelength type-II InAs/GaSb superlattice photodetector using resonant tunneling diode (RTD) structure. The linewidth of the satellite peak of the x-ray diffraction curve of the as-grown sample is only 15.7 arcsec showing a very high structural quality. The response maximum wavelength of the RTD detector is 7.5 μm and the 50% cutoff wavelength is 9.6 μm at 77 K. The measured QE is 147% at 7.5 μm when the applied bias voltage is 1.45 V and the corresponding responsivity is 8.9 A/W. This unusual QE is attributed to a large gain achieved when the device is under a resonant tunneling condition. The corresponding shot noise limited detectivity D* is 1.2×1010cm · Hz/W at 1.45 V at 77 K.
关键词： long wavelength,InAs/GaSb superlattice,quantum efficiency,resonant tunneling diode,type II
更新于2025-09-11 14:15:04
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Long Wavelength Infrared Quantum Cascade Detector
摘要： The effect of the barrier width in the photovoltaic-type quantum cascade detector structure on the responsivity and the zero-bias resistance of the device are opposite. A wide barrier can increase the zero-bias resistance but hinder the transport of photo-generated carriers and decrease the responsivity. The design of a long wave infrared cascade detector usually focuses on increasing the zero bias resistance by using wide barriers to lower the thermal noise, but the photocurrent might be low in this case. Even though the thermal noise that dominates the noise performance of a photovoltaic quantum cascade detector is very low, it is possible that effective photoresponse signals cannot be obtained when the photocurrent is as low as the noise current of measurement circuits, which might be higher than the thermal noise of the detector itself. In this work, we modified the structure of our previous long wavelength infrared quantum cascade detector by increasing the number of cascaded stages, while reducing the barrier thickness to improve the responsivity of the device. Although the device’s zero bias resistance decreases due to thinning of the barrier, the detectivity is almost unaffected due to the significant increase in response. More importantly, the operating temperature of the device is increased. Therefore, optimization of long wave infrared QCDs should consider both the resistance and the photocurrent flow.
关键词： Quantum Cascade Photodetector,Long Wavelength Infrared
更新于2025-09-04 15:30:14