Performance improvement of HgCdTe photoconductive detectors

Sano, Masahiko; Miyamoto, Keiji; Oda, Naoki; Fujino, Yoshio

doi:10.1117/12.243450

Cited by 2 publications

(2 citation statements)

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“…A D * of only 5 × 10 7 (at 10 µm) at room temperature (Galus et al 1979) has been reported. Also, for cooled operation at 77 K smaller values than theoretically expected have been achieved: D * = 1.5 × 10 10 (at 8-10.5 µm) (Potet 1996) and D * = 1.0 × 10 11 (at 5-8 µm) (Sano et al 1996). Obviously, quantum detectors are greatly handicapped in the far-IR by the fact that their intrinsic noise power increases exponentially with temperature (thermal excitation across the semiconductor gap), whereas the dielectric noise of pyroelectrics, or the Johnson noise of thermistors, increases only as the square root of temperature.…”

Section: The Limits Of Pyroelectric Detection Comparison With Photon ...mentioning

confidence: 86%

Micromachined infrared detectors based on pyroelectric thin films

2001

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The state of the art of thin-film pyroelectric infrared (IR) detectors is reviewed covering device physics, material performance, micro-fabrication and device examples. Emphasis is given to special issues related to thin films, such as small heat capacities and the substrate influence on the pyroelectric properties. For the latter, an overview of the hitherto reported values is given. Examples of micromachined IR detectors based on pyroelectric thin films are described. The ultimate limit of micromachined thermal IR detectors is estimated for uncooled operation. It is concluded that the best pyroelectric thin films achieved to date are in principle sufficiently good to approach this limit, meaning that the present performance of pyroelectric thin-film focal plane arrays can still be improved by more than a factor of 10. A comparison of the different principles for IR detection shows that pyroelectricity is indeed one of the most competitive principles for uncooled IR detection. The major obstacle hindering quick industrialization is the fabrication complexity.

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Section: The Limits Of Pyroelectric Detection Comparison With Photon ...mentioning

confidence: 86%

Micromachined infrared detectors based on pyroelectric thin films

2001

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“…Pixels with sensitive area size W×∆L = 50×50 µ m were either standard quadrant with length of semiconductor slab along bias current path equals to L = ∆ L = 50 µ m or with "shadowing" shield ( Fig. 4B) eliminating "sweep-out" effect of minority charge carriers 16,17 and with length of semiconductor slab along bias current path equals to L = 140 µ m. Devices were tested for spectral response, I-V curve, responsivity R V and low-frequency noise spectral density (NSD) at different background flux density (T bgr ≈ 300 K) at T op ≈ 290 -300 K and 78 K. Excess charge carriers were excited in sensitive structure by illumination through front graded-gap adjacent layer (Fig. 3).…”

Section: Metering Set-upmentioning

confidence: 99%

Variation of generation-recombination noise density with 300 K background flux in epitaxial LWIR Hg 1-x Cd x Te photoconductors having three-layer light absorbing configuration

Chekanova¹,

Drugova

Kurbatov³

et al. 2005

SPIE Proceedings

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Spectral density of "generation-recombination" noise voltage <δV 2 gr > ("g-r noise") in photoconductive Hg 1-x Cd x Te infrared radiation detectors with absorber n-Hg 1-x Cd x Te layer was calculated. Variations of <δV 2 gr > with doping level (n ≈ N d ), ambient background flux density (Q bgr , T bgr ≈ 300 K), electrical bias (V b /I b ) and pixel active area were analyzed. Spectral density of low-frequency noise as superposition of Flicker-noise "1/f", g-r noise resulting from fluctuations in generation-recombination rates of equilibrium (thermal) charge carriers <δV 2 gr,th > and excess charge carriers exited by background photons <δV 2 gr,bgr > and Johnson-Nyquist noise <δV 2 JN > were examined in small active area (30 µm × 30 µm and 50 µm × 50 µm) Hg 1-x Cd x Te photoconductors based on MBE-grown multi-layer structures. Noise measurements were performed on Long-Wave (LWIR) PC MCT detectors with responsivity peak wavelength 10 ≤ λ p ≤ 12 µ m at operating temperature T op ≈ 78 K. Tested PC MCT detectors show extremely low spectral density of excess. Measured dependencies of g-r noise voltage spectral density have confirmed BLIP mode of photoconductors up to FOV=10 0 where D*(λ p ) exceed 2×10 11 Jones.

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Performance improvement of HgCdTe photoconductive detectors

Cited by 2 publications

References 0 publications

Micromachined infrared detectors based on pyroelectric thin films

Micromachined infrared detectors based on pyroelectric thin films

Variation of generation-recombination noise density with 300 K background flux in epitaxial LWIR Hg 1-x Cd x Te photoconductors having three-layer light absorbing configuration

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