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Keywords HgCdTe APD LWIR MWIR
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Abstract

The performance of long-wave infrared (LWIR) x = 0.22 HgCdTe avalanche photodiodes (APDs) was presented. The dark current-voltage characteristics at temperatures 200 K, 230 K, and 300 K were measured and numerically simulated. Theoretical modeling was performed by the numerical Apsys platform (Crosslight). The effects of the tunneling currents and impact ionization in HgCdTe APDs were calculated. Dark currents exhibit peculiar features which were observed experimentally. The proper agreement between the theoretical and experimental characteristics allowed to determine the material parameters of the absorber was reached. The effect of the multiplication layer profile on the detector characteristics was observed but was found to be insignificant.
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Authors and Affiliations

Tetiana Manyk
ORCID: ORCID
Jan Sobieski
ORCID: ORCID
Kacper Matuszelański
Jarosław Rutkowski
ORCID: ORCID
Piotr Martyniuk
ORCID: ORCID
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Abstract

The paper reports on a long-wave infrared (cut-off wavelength ~ 9 μm) HgCdTe detector operating under nbiased condition and room temperature (300 K) for both short response time and high detectivity operation. The ptimal structure in terms of the response time and detectivity versus device architecture was shown. The response time of the long-wave (active layer Cd composition, xCd = 0.19) HgCdTe detector for 300 K was calculated at a level of τs ~ 1 ns for zero bias condition, while the detectivity − at a level of D* ~ 109 cmHz1/2/W assuming immersion. It was presented that parameters of the active layer and P+ barrier layer play a critical role in order to reach τs ≤ 1 ns. An extra series resistance related to the processing (RS+ in a range 5−10 Ω) increased the response time more than two times (τs ~ 2.3 ns).

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Authors and Affiliations

Piotr Martyniuk
Małgorzata Kopytko
Paweł Madejczyk
Aleksandra Henig
Kacper Grodecki
Waldemar Gawron
Jarosław Rutkowski
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Abstract

Current advances in type-II superlattice (T2SL) research at Fraunhofer IAF are elaborated on in this paper. First, the use of metastructures for quantum efficiency (QE) enhancement in the longwave infrared (LWIR) is presented. Finite element modelling results are reported on that suggest a potential for doubling of the QE at certain wavelengths with the investigated device structure. Next, characterisation results of midwave infrared (MIWR) InAs/InAsSb T2SL nBn detectors are shown. The low, diffusion-limited dark current above 120 K and a QE of 60% are comparable to the state-of-the-art. Finally, groundwork for InAs/GaSb T2SL MWIR/LWIR dual-band detector arrays based on a back-to-back heterojunction diode device concept is presented. The dry etching technology allows for steep etch trenches and full pixel reticulation with a fill factor of about 70% at 12 µm pitch. The detector characterisation at 77 K and ±250 mV bias demonstrates the bias-switchable operation mode with dark current densities of 6.1·10−9 A/cm² in the MWIR and 5.3·10−4 A/cm² in the LWIR.
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Authors and Affiliations

Raphael Müller
1
Volker Daumer
1
Tsvetelina Hugger
1
Lutz Kirste
1
Wolfgang Luppold
1
Jasmin Niemasz
1
Robert Rehm
1
Tim Stadelmann
1
Mark Wobrock
1
Quankui Yang
1

  1. Fraunhofer Institute for Solid State Physics IAF, Tullastraße 72, 79108 Freiburg, Germany

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