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Enhancing the Performance of Commercial Infrared Detectors by Surface Plasmons
摘要： The feasibility to improve the response of quantum type (photonic) infrared (IR) detectors by applying surface plasmons is investigated. The HgCdTe material system is used as the detector platform of interest for which selected plasmonic structures and materials are applied and the influence studied by full-fielded electromagnetic simulations. It is shown that even for the several-micrometers-thick detector structures, similar to the commercial ones, broadband absorption enhancements of 30–40% can be achieved. The results suggest that improved, or new, pixel-level functionalities can be created for commercial IR detectors by relatively simple means. Additionally, high potential for cost reduction in high-performance IR imaging systems with multicolour capabilities is foreseen.
关键词： plasmonics,finite element method,computational simulations,infrared detectors
更新于2025-09-23 15:23:52
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Carrier concentration and transport in Be-doped InAsSb for infrared sensing applications
摘要： Accurate p-type doping of the active region in III-V infrared detectors is essential for optimizing the detector design and overall performance. While most III-V detector absorbers are n-type (e.g., nBn), the minority carrier devices with p-type absorbers would be expected to have relatively higher quantum efficiencies due to the higher mobility of minority carrier electrons. However, there are added challenges to determining the hole carrier concentration in narrow bandgap InAsSb due to the potential for electron accumulation at the surface of the material and at its interface with the layer grown directly below it. Electron accumulation layers form high conductance electron channels that can dominate both resistivity and Hall-effect transport measurements. Therefore, to correctly determine the bulk hole concentration and mobility, temperature- and magnetic-field-dependent transport measurements in conjunction with Multi-Carrier Fit analysis were utilized on a series of p-doped InAs0.91Sb0.09 samples on GaSb substrates. The resulting hole concentrations and mobilities at 77 K (300 K) are 1.6×1018 cm-3 (2.3×1018 cm-3) and 125 cm2 V-1 s-1 (60 cm2 V-1 s-1), respectively, compared with the intended Be-doping of ~2×1018 cm-3. A surface treatment experiment is conducted to associate one of the electron conducting populations to the surface. Variable temperature (15 – 390 K) measurements confirmed the different carrier species present in the sample and enabled the extraction of the bulk heavy hole, interface carriers and surface electron transport properties. For the bulk carrier, a thermal activation of intrinsic carriers is identified at high temperatures with a bandgap of EG ~ 258 meV and the low temperature data suggests an activation energy of EA ~ 22 meV for the Be dopant atoms. Finally, temperature analysis confirms a surface carrier electron with resulting mobilities and sheet concentrations at 30 K (300 K) of 4500 cm2 V-1 s-1 (4300 ± 100 cm2 V-1 s-1) and 5.6×1010 cm-2 (6×1010 ± 2×1010 cm-2), respectively.
关键词： Hall-effect measurements,magneto-transport,beryllium doping,III-V infrared detectors,InAsSb
更新于2025-09-23 15:21:21
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Heterojunction Internal Photoemission of λ ~ 2.8 μm by Ge/Si Core/Shell Nanowires
摘要： The photodetector of Ge/Si core/shell nanowires can detect 2.8-μm-long infrared, far beyond the absorption edge of both semiconductors, at room temperature. The device of single nanowire grown on heavily doped Si (111) shows typical rectifying behavior despite p–p isotype of nanowire and substrate. Under illumination, the present devices show large responsivity of 35 A/W at ?0.5 V. The analysis of current–voltage characteristics shows that Ge/Si nanowire on p-type silicon device follows the model of semiconductor heterojunction rather than Schottky junction. This result implies that the interface between nanowire and substrate is the main barrier of charge transport in the present nanowire infrared detector. In this paper, the parameter values of the heterojunction of nanowire and substrate are quantitatively investigated with the thermionic transport model. The analysis of the energy band structure shows that even longer wavelength infrared can be detected through the photoemission of the holes over the reduced heterojunction barrier of 0.37 eV.
关键词： Infrared detectors,photoemission,nanowire
更新于2025-09-23 15:21:01
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Fabrication and characterization of sensitive vertical P-i-N germanium photodiodes as infrared detectors
摘要： Germanium on silicon P-i-N photodetectors fabricated using standard CMOS tools are now successfully used as uncooled detectors in the near-infrared (NIR), which extends from 0.75 to 1.4 μm and in the short-wave infrared (SWIR), which extends from 1.4 to 3 μm. They feature a remarkably high responsivity up to 1550 nm and a low dark current when they are operated at reverse biases. The aim is to achieve a very low dark current density and a high responsivity with a small Germanium photodiode pitch. In this paper we discuss the fabrication and the characterization of vertical P-i-N photodiodes with the epitaxy of Germanium on Silicon. The Germanium epilayer is a 1.3 μm thick Ge ?lm with a bottom Ge layer P-type doped with boron at 1019 cm?3 and a top Ge layer N-type doped with phosphorus at 1020 cm?3. Secondary ion mass spectroscopy was used to assess the doping level of the Phosphorus doped N?+?region. The strain in the Germanium epilayer on Silicon substrate was investigated. It was tensile, with a value around +0.15% from x-ray diffraction (XRD), in good agreement with a +0.12% value from Raman spectroscopy. In this paper, we focus on P-i-N photodiodes with a circular shape and a diameter of 10 μm. Electrical characterizations were performed in dark and under NIR-SWIR radiation (1310 nm, 1550 nm), with very low dark current of 0.45 nA and enhanced photocurrent at ?1 V. The external responsivities were measured at 0.275 and 0.133 A W?1 for 1310 nm and 1550 nm, respectively. Finally, internal quantum ef?ciencies of the fabricated vertical P-i-N photodiodes were extracted at 66% and 52% at 1310 nm and 1550 nm, respectively, in good agreement with TCAD simulations. Finally, a measurement of the noise in dark conditions is presented.
关键词： infrared detectors,photodiodes,strain,germanium
更新于2025-09-23 15:19:57
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CVD preparation of vertical graphene nanowalls/VO2 (B) composite films with superior thermal sensitivity in uncooled infrared detector
摘要： Vanadium dioxide with superior thermal sensitivity is one of the most preferred materials used in microbolometer, and the B phase of VO2 is particularly prominent. However, conventional VO2 (B) undergoes low temperature-coefficient of resistance (TCR) values and large resistances. In this paper, simple controllable composite films of vertical graphene nanowalls/VO2 (B) (i.e., VGNWs/VO2 (B)) with a suitable square resistance (12.98 k?) and a better temperature-coefficient of resistance (TCR) (-3.2 %/K) were prepared via low pressure chemical vapor deposition. The VGNWs can provide a fast channel for electron transport and enhance the conductivity of VO2 (B). This preparation method can provide a low cost, facile and simple pathway for the design and fabrication of high performance VO2 (B) thin films with superior electrical properties for its application in uncooled infrared detectors.
关键词： Chemical vapor deposition,VO2 (B) films,Vertical graphene nanowalls,Uncooled infrared detectors
更新于2025-09-23 15:19:57
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2D Material-enabled Nanomechanical Bolometer
摘要： We here describe a novel type of long-wavelength radiation detector that measures illumination intensity at room temperature through mechanical transduction. Compared to semiconductor-based bolometers, our nanomechanical detector exhibits low measurement noise and is inherently transparent and flexible. The presented solid-state device is based on a 2D-material film that acts as radiation absorber and detector of mechanical strain at the substrate-absorber interface. Optimization of the 2D material properties and realization of a novel edge-on device geometry combines unprecedented detectivity of 3.34 × 108 cm Hz1/2 W-1 with micrometer-scale spatial resolution. The observed combination of superior performance with the facile and scalable fabrication using only liquid processes shows the potential of the presented detector for future ubiquitous and wearable electronics.
关键词： thermal expansion,MoS2,infrared detectors,graphene,Bolometer
更新于2025-09-23 15:19:57
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A Data-Driven Home Energy Scheduling Strategy Under the Uncertainty in Photovoltaic Generations
摘要： We report the fabrication of InAs planar avalanche photodiodes (APDs) using Be ion implantation. The planar APDs have a low background doping of 2 × 1014 cm?3 and large depletion widths approaching 8 μm. The thick depletion width enabled a gain of 330 to be achieved at ?26 V at 200 K without inducing a significant tunneling current. No edge breakdown was observed within the APDs. The surface leakage current was found to be low with a gain normalized dark current density of 400 μAcm?2 at ?20 V at 200 K.
关键词： Avalanche photodiodes,ion implantation,infrared detectors
更新于2025-09-23 15:19:57
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MSM-photodetector with ZnSe/ZnS/GaAs Bragg reflector
摘要： The effect of a ZnSe/ZnS/GaAs distributed Bragg reflector on the spectral response of a metal–semiconductor–metal (MSM)-diode is investigated. Good agreement is obtained between the calculated and experimental reflection spectra of the ZnSe/ZnS/GaAs heterostructure forming a distributed Bragg reflector in the MSM-diode. The MSM-detector provides a two-color response at 420 and 472 nm, a sharp decrease in photosensitivity in the long-wave part of the response signal, high quantum efficiency of 53%, and low dark current of 5 × 10?10 A. The two-color response of the detector can be adjusted to the desired wavelength by appropriately selecting the heterostructure parameters.
关键词： Metal–semiconductor–metal (MSM) diode,Dark current,Heterostructure,Infrared detectors,Bragg reflector,Spectral response
更新于2025-09-19 17:13:59
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - High Average Power Picosecond Thulium-doped All-fiber Amplifier
摘要： We report the fabrication of InAs planar avalanche photodiodes (APDs) using Be ion implantation. The planar APDs have a low background doping of 2 × 1014 cm?3 and large depletion widths approaching 8 μm. The thick depletion width enabled a gain of 330 to be achieved at ?26 V at 200 K without inducing a significant tunneling current. No edge breakdown was observed within the APDs. The surface leakage current was found to be low with a gain normalized dark current density of 400 μAcm?2 at ?20 V at 200 K.
关键词： ion implantation,infrared detectors,Avalanche photodiodes
更新于2025-09-19 17:13:59
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[IEEE IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium - Yokohama, Japan (2019.7.28-2019.8.2)] IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium - NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) on-Orbit Band-To-Band Registration Estimation for Reflective Solar Band (RSB) Using Scheduled Lunar Collections
摘要： We report the fabrication of InAs planar avalanche photodiodes (APDs) using Be ion implantation. The planar APDs have a low background doping of 2 × 1014 cm?3 and large depletion widths approaching 8 μm. The thick depletion width enabled a gain of 330 to be achieved at ?26 V at 200 K without inducing a significant tunneling current. No edge breakdown was observed within the APDs. The surface leakage current was found to be low with a gain normalized dark current density of 400 μAcm?2 at ?20 V at 200 K.
关键词： infrared detectors,ion implantation,Avalanche photodiodes
更新于2025-09-19 17:13:59