Infrared sensors are an essential technology in the rapid detection and identification of potential threats. Continuous improvements in performance and yield as well as reductions in cost, size, weight, and power consumption are necessary to keep pace with new and emerging threats that are increasing in number and have greater range, speed, and maneuverability. Yield and performance limiting challenges of cooled infrared detector materials and infrared focal plane array processing will be discussed. Paths to addressing some of these challenges including surface passivation, defect identification and analysis, and pixel definition will be presented.
Conventional photodetectors based on HgCdTe material and designed to absorb mid-wave infrared (MWIR) band wavelengths typically require cryogenic or at minimum thermoelectric cooling to maintain adequate levels of infrared (IR) sensing performance. This cooling requirement invariably entails augmentations in size, power, and cost, which for space and satellite applications such as remote sensing and earth observation generally are limiting in scope and potentially prohibitive. Here we report a scalable, low cost, low power, and small footprint room temperature operating MWIR sensing device involving the integration of bilayer graphene functioning as a high mobility channel with HgCdTe material, to limit the recombination of photogenerated carriers and achieve higher performance detection over the 2-5 μm MWIR without the need of an additional cooling mechanism. For the development of these graphene-enhanced HgCdTe MWIR photodetectors, graphene bilayers on Si/SiO2 substrates were doped with boron using a spin-on dopant (SOD) process, and then transferred onto HgCdTe substrates for enhanced higher-mobility photodetection. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and secondary-ion mass spectroscopy (SIMS) were employed to analyze dopant levels and structural properties of the graphene through various stages of the development process and characterize the p-doped graphene following doping and transfer. The features and enhanced performance of the room-temperature operating graphene-based HgCdTe MWIR detectors were demonstrated through modeling, material characterization, and measurements of detector IR sensitivity and response performance.
A scalable, low cost, low power, and small footprint uncooled mid-wave infrared (MWIR) sensing technology capable of measuring thermal dynamics with high spatial resolution can be of great benefit to space and satellite applications such as remote sensing and earth observation. Conventional photodetectors designed to absorb MWIR band wavelengths have often been based on HgCdTe material and typically require cooling. However, through integration of bilayer graphene functioning as a high mobility channel with HgCdTe material in photodetectors, higher performance detection over the 2-5 μm MWIR band may be enabled and facilitated primarily by thus limiting recombination of photogenerated carriers in these detectors. This high performance MWIR band detector technology is being developed and tested for NASA Earth Science, defense, and commercial applications. Graphene bilayers on Si/SiO2 substrates are doped with boron using a spin-on dopant (SOD) process and then transferred onto HgCdTe substrates for enhanced mobility photodetection applications. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and secondary-ion mass spectroscopy (SIMS) were utilized for analysis of dopant levels and structural properties of the graphene throughout various stages of the development process to characterize the p-doped graphene following doping and transfer. The enhanced performance and functional capabilities of the room-temperature operating graphene-based HgCdTe MWIR detectors and arrays are thereby demonstrated through modeling, material development and characterization, and device optimization.
High performance detector technology is being developed for sensing over the mid-wave infrared (MWIR) band for NASA Earth Science, defense, and commercial applications. The graphene-based HgCdTe detector technology involves integration of graphene with HgCdTe photodetectors allowing higher performance detection over 2-5 μm compared with photodetectors using only HgCdTe material. The graphene layer functioning as a high mobility channel reduces recombination of photogenerated carriers in the detector to further enhance performance. Graphene bilayers on Si/SiO2 substrates have been doped with boron using a spin-on dopant (SOD) process. The p-doped graphene is then transferred onto HgCdTe substrates for high mobility layers in MWIR photodetectors. Various characterization techniques including Raman spectroscopy and secondary-ion mass spectroscopy (SIMS) have analyzed dopant levels and properties of the graphene throughout various stages of development to qualify and quantify the graphene doping and transfer. The objective of this work is demonstration of graphene-based HgCdTe room temperature MWIR detectors and arrays through modeling, material development, and device optimization. The primary driver for this technology development is enablement of a scalable, low cost, low power, and small footprint uncooled MWIR sensing technology capable of measuring thermal dynamics with better spatial resolution for applications such as remote sensing and earth observation.
High performance detector technology is being developed for sensing over the mid-wave infrared (MWIR) band for NASA Earth Science, defense, and commercial applications. The graphene-based HgCdTe detector technology involves the integration of graphene with HgCdTe photodetectors that combines the best of both materials, and allows for higher MWIR (2-5 μm) detection performance compared with photodetectors using only HgCdTe material. The interfacial barriers between the HgCdTe-based absorber and the graphene act as a tunable rectifier that reduces the recombination of photogenerated carriers in the detector. The graphene layer also acts as high mobility channel that whisks away carriers before they recombine, further enhancing detection performance. This makes them much more practical and useful for MWIR sensing applications such as remote sensing and earth observation, e.g., in smaller satellite platforms (CubeSat) for measurement of thermal dynamics with better spatial resolution. The objective of this work is to demonstrate graphene-based HgCdTe room temperature MWIR detectors and arrays through modeling, material development, and device optimization. The primary driver for this technology development is the enablement of a scalable, low cost, low power, and small footprint infrared technology component that offers high performance, while opening doors for new earth observation measurement capabilities.
Conference Committee Involvement (8)
Image Sensing Technologies: Materials, Devices, Systems, and Applications XII
13 April 2025 | Orlando, Florida, United States
Image Sensing Technologies: Materials, Devices, Systems, and Applications XI
22 April 2024 | National Harbor, Maryland, United States
Image Sensing Technologies: Materials, Devices, Systems, and Applications X
1 May 2023 | Orlando, Florida, United States
Image Sensing Technologies: Materials, Devices, Systems, and Applications IX
4 April 2022 | Orlando, Florida, United States
Image Sensing Technologies: Materials, Devices, Systems, and Applications VIII
12 April 2021 | Online Only, Florida, United States
Image Sensing Technologies: Materials, Devices, Systems, and Applications VII
27 April 2020 | Online Only, California, United States
Image Sensing Technologies: Materials, Devices, Systems, and Applications VI
15 April 2019 | Baltimore, MD, United States
Image Sensing Technologies: Materials, Devices, Systems, and Applications V
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