Design Principles for High QE HgCdTe Infrared Photodetectors for eSWIR Applications

Akhavan, Nima Dehdashti; Umana‐Membreno, Gilberto A.; Gu, Runxia; Antoszewski, J.; Faraone, Lorenzo

doi:10.1007/s11664-022-09809-y

Cited by 13 publications

(8 citation statements)

References 45 publications

(57 reference statements)

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“…Based on preliminary results presented below, the electron minority carrier lifetime in Hg0.51Cd0.49Te grown by MBE on CdZnTe substrates is estimated to significantly exceed 50 ns. Our simulation results indicate that ultra-high QE >99% can be achieved in the Hg-vacancy doped n-on-p photodetector technology due to the long diffusion length of the minority carriers, and similarly in low-doped p-on-n technology with ND <10 14 cm -3 [11]. cm -3 for both n-on-p and p-on-n photodetector technologies.…”

Section: Theoretical Modelling Of Qe and Device Designmentioning

confidence: 74%

“…The detector structure shown in Figure 5 is a planar n-on-p photodiode in which the absorber layer is Hg1-xCdxTe with an alloy composition chosen to be x=0.45, which corresponds to a cut-off wavelength of λco=2.5 μm at the chosen elevated temperature of T=200 K (2.6 μm cut-off at T=80 K). More simulation details can be found in our recent report [11].…”

Section: Theoretical Modelling Of Qe and Device Designmentioning

confidence: 99%

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Narrow bandgap HgCdTe technology for IR sensing and imaging focal plane arrays

Pan

Umana‐Membreno²,

Antoszewski³

et al. 2022

Electro-Optical and Infrared Systems: Technology and Applications XIX

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High performance infrared (IR) sensing and imaging systems require IR optoelectronic detectors that have a high signalto-noise ratio (SNR) and a fast response time, and that can be readily hybridised to CMOS read-out integrated circuits (ROICs). From a device point of view, this translates to p-n junction photovoltaic detectors based on narrow bandgap semiconductors with a high quantum efficiency (signal) and low dark current (noise). These requirements limit the choice of possible semiconductors to those having an appropriate bandgap that matches the wavelength band of interest combined with a high optical absorption coefficient and a long minority carrier diffusion length, which corresponds to a large mobility-lifetime product for photogenerated minority carriers. Technological constraints and modern clean-room fabrication processes necessitate that IR detector technologies are generally based on thin-film narrow bandgap semiconductors that have been epitaxially grown on lattice-matched wider bandgap IR-transparent substrates. The basic semiconductor material properties have led to InGaAs (in the SWIR up to 1.7 microns), InSb (in the MWIR up to 5 microns), and HgCdTe (in the eSWIR, MWIR and LWIR wavelength bands) being the dominant IR detector technologies for high performance applications. In this paper, the current technological limitations of HgCdTe-based technologies will be discussed with a view towards developing future pathways for the development of next-generation IR imaging arrays having the features of larger imaging array format and smaller pixel pitch, higher pixel yield and operability, higher quantum efficiency (QE), higher operating temperature (HOT), and dramatically lower per-unit cost.

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Section: Theoretical Modelling Of Qe and Device Designmentioning

confidence: 74%

Section: Theoretical Modelling Of Qe and Device Designmentioning

confidence: 99%

Narrow bandgap HgCdTe technology for IR sensing and imaging focal plane arrays

Pan

Umana‐Membreno²,

Antoszewski³

et al. 2022

Electro-Optical and Infrared Systems: Technology and Applications XIX

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“…HgCdTe is the narrow bandgap semiconductor material with a direct band gap and its forbidden bandwidth is adjustable from 0 to 1.6 eV, covering from short-wave infrared to very long-wave infrared regions [3]. It also has the advantages of high quantum efficiency and absorption coefficient [4], which determine the irreplaceable position of HgCdTe material in the field of infrared detectors. HgCdTe photovoltaic detectors use the photovoltaic effect to convert light signals into electrical signals, having the advantages of high target resolution, fast response time, low power consumption and good reliability [5].…”

Section: Introductionmentioning

confidence: 99%

Impact of nitrogen annealing on the electrical properties of HgCdTe epitaxial films

Jin

Zhou

et al. 2023

Mater. Res. Express

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The nitrogen annealing of HgCdTe materials grown by molecular beam epitaxy (MBE) was carried out to manipulate their electrical properties. The results show that the annealing temperature, annealing time and cooling process all have significant influences on the electrical properties of HgCdTe materials. Excessive annealing temperature or long annealing time can make voids emerge on the surface of the CdTe passivation layer. Carrier concentration and mobility vary exponentially with annealing time and they reach an equilibrium value determined by annealing temperature over a long annealing duration. Moreover, time constants are given and a longer time is needed for mobility to reach an equilibrium value than carrier concentration. The relationship between equilibrium carrier concentration and annealing temperature is given and the activation energy under nitrogen annealing is calculated as 0.63 eV. For a long cooling duration, Hg vacancies are annihilated by Hg atoms diffusion, which makes carrier concentration lower and mobility higher. In addition, some outlier data were found in this experiment and explained by the combination between Te antisites and Hg vacancies.

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“…To date, eSWIR focal planes are not widely available or as developed as Vis, NIR, and SWIR, but interest exists, and recent developments in mercury cadmium telluride (HgCdTe) focal plane array (FPA) technology will expedite their adoption 6 – 8 The midwave infrared (MWIR) thermal band from 3 to 5 μm has been well developed and widely used, particularly on airborne platforms 4 . However, the longer wavelength of MWIR leads to a larger diffraction blur than eSWIR for a given aperture size, which reduces range performance.…”

Section: Introductionmentioning

confidence: 99%

Target discrimination in the extended shortwave infrared band (2 to 2.5μm) compared with visible, near-infrared, and SWIR in degraded visual environments

et al. 2022

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.Long-range target identification is well studied in the visible (Vis) and near-infrared (NIR) bands and more recently in the shortwave infrared (SWIR). The longer wavelength of SWIR (1 to 1.7 μm) improves target detection for both long ranges and under challenging atmospheric conditions because it is less limited by scattering and absorption in the atmosphere. For these reasons, SWIR sensors are proliferating on military platforms. The extended shortwave infrared (eSWIR) band spanning from 2 to 2.5 μm is not typically limited by diffraction, and as a result, the band benefits target acquisition both at long ranges and for degraded visual environments (DVEs). Theoretical and experimental data compare eSWIR with Vis, NIR, and SWIR for atmospheric transmission, reflectivity, illumination, and sensor resolution and sensitivity. The experimental setup includes two testbeds, each with four cameras. The first is a wide field of view (FOV) testbed matching FOV at 20 deg for each camera. The second is a narrow FOV telescope testbed to match instantaneous FOV for consistent resolution across all four bands at long ranges. Both the theory and experiment demonstrate advantages of using eSWIR for long-range target identification under DVEs.

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Design Principles for High QE HgCdTe Infrared Photodetectors for eSWIR Applications

Cited by 13 publications

References 45 publications

Narrow bandgap HgCdTe technology for IR sensing and imaging focal plane arrays

Narrow bandgap HgCdTe technology for IR sensing and imaging focal plane arrays

Impact of nitrogen annealing on the electrical properties of HgCdTe epitaxial films

Target discrimination in the extended shortwave infrared band (2 to 2.5μm) compared with visible, near-infrared, and SWIR in degraded visual environments

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