Applied sciences

Opto-Electronics Review

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Opto-Electronics Review | 2023 | 31 | special issue

Authors and Affiliations

Piotr Martyniuk
ORCID: ORCID
Sarath D. Gunapala
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Abstract

The operation of narrow-gap semiconductor devices under non-equilibrium mode is used at temperatures where the materials are normally intrinsic. The phenomenon of minority carrier exclusion and extraction was particularly discussed in the case of the suppression of Auger thermal generation in heterojunction photodiodes, especially important in the long-wave infrared range. This paper shows that the reduction of the dark current in the HgCdTe photodiode operating in the mid-wave infrared range is primarily the result of suppression of the Shockley-Read-Hall generation in the non-equilibrium absorber. Under a reverse bias, the majority carrier concentration is held equal to the majority carrier doping level. This effect also leads to a decreased majority carrier population at the trap level and an effective increase in the carrier lifetime. The analysed device was with the following design: p+-Bp cap-barrier unit, p-type absorber doped at the level of 8 ·1015 cm−3, and wide-bandgap N+ bottom contact layer. At room temperature, the lowest dark current density of 3.12 ·10−1 A/cm2 was consistent with the theoretically predicted Shockley-Read-Hall suppression mechanism, about two times smaller than for the equilibrium case.
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Authors and Affiliations

Małgorzata Kopytko
1
ORCID: ORCID

  1. Institute of Applied Physics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00 908 Warsaw, Poland
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Abstract

In the past ten years, InAs/InAsSb type-II superlattice has emerged as a promising technology for high-temperature mid-wave infrared photodetector. Nevertheless, transport properties are still poorly understood in this type of material. In this paper, optical and electro-optical measurements have been realised on InAs/InAsSb type-II superlattice mid-wave infrared photodetectors. Quantum efficiency of 50% is measured at 150 K, on the front side illumination and simple pass configuration. Absorption measurement, as well as lifetime measurement are used to theoretically calculate the quantum efficiency thanks to Hovel’s equation. Diffusion length values have been extracted from this model ranging from 1.55 µm at 90 K to 7.44 µm at 200 K. Hole mobility values, deduced from both diffusion length and lifetime measurements, varied from 3.64 cm²/Vs at 90 K to 37.7 cm²/Vs at 200 K. The authors then discuss the hole diffusion length and mobility variations within temperature and try to identify the intrinsic transport mechanisms involved in the superlattice structure.
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Authors and Affiliations

Maxime Bouschet
1 2
Vignesh Arounassalame
3
Anthony Ramiandrasoa
3
Jean-Philippe Perez
1
Nicolas Péré-Laperne
2
Isabelle Ribet-Mohamed
3
Philippe Christol
1

  1. IES, Université de Montpellier, CNRS, 860 Saint Priest St., F-34000 Montpellier, CEDEX 5, France
  2. LYNRED, BP 21, 364 de Valence Ave., 38113 Veurey-Voroize, France
  3. ONERA, Chemin de la Hunière, F-91761 Palaiseau Cedex, France
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Abstract

Germanium (Ge) PiN photodetectors are fabricated and electro-optically characterised. Unintentionally and p-type doped Ge layers are grown in a reduced-pressure chemical vapour deposition tool on a 200 mm diameter, <001>-oriented, p-type silicon (Si) substrates. Thanks to two Ge growth temperatures and the use of short thermal cycling afterwards, threading dislocation densities down to 107 cm−2 are obtained. Instead of phosphorous (P) ion implantation in germanium, the authors use in situ phosphorous-doped poly-crystalline Si (poly-Si) in the n-type regions. Secondary ion mass spectrometry revealed that P was confined in poly-Si and did not diffuse in Ge layers beneath. Over a wide range of tested device geometries, production yield was dramatically increased, with almost no short circuits. At 30 °C and at −0.1 V bias, corresponding to the highest dynamic resistance, the median dark current of 10 µm diameter photodiodes is in the 5–20 nA range depending on the size of the n-type region. The dark current is limited by the Shockley-Read-Hall generation and the noise power spectral density of the current by the flicker noise contribution. A responsivity of 0.55 and 0.33 A/W at 1.31 and 1.55 µm, respectively, is demonstrated with a 1.8 µm thick absorption Ge layer and an optimized anti-reflection coating at 1.55 µm. These results pave the way for a cost-effective technology based on group-IV semiconductors.
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Authors and Affiliations

Quentin Durlin
1
Abdelkader Aliane
1
Luc André
1
Hacile Kaya
1
Mélanie Le Cocq
1
Valérie Goudon
1
Claire Vialle
1
Marc Veillerot
1
Jean-Michel Hartmann
1

  1. Univ. Grenoble Alpes, CEA-Leti, F-38000 Grenoble, France
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Abstract

This paper presents examples of infrared detectors with mercury cadmium telluride elaborated at the Institute of Applied Physics, Military University of Technology and VIGO Photonics S.A. Fully doped HgCdTe epilayers were grown with the metal organic chemical vapour deposition technique which provides a wide range of material composition covering the entire infrared range from 1.5 µm to 14 µm. Fundamental issues concerning the design of individual areas of the heterostructure including: the absorber, contacts, and transient layers with respect to their thickness, doping and composition were discussed. An example of determining the gain is also given pointing to the potential application of the obtained devices in avalanche photodiode detectors that can amplify weak optical signals. Selected examples of the analysis of current-voltage and spectral characteristics are shown. Multiple detectors based on a connection in series of small individual structures are also presented as a solution to overcome inherent problems of low resistance of LWIR photodiodes. The HgCdTe detectors were compared with detectors from III-V materials. The detectors based on InAs/InAsSb superlattice materials achieve very comparable parameters and, in some respects, they are even superior to those with mercury cadmium telluride.
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Authors and Affiliations

Paweł Madejczyk
1
ORCID: ORCID
Waldemar Gawron
1 2
ORCID: ORCID
Jan Sobieski
2
ORCID: ORCID
Piotr Martyniuk
1
ORCID: ORCID
Jarosław Rutkowski
1
ORCID: ORCID

  1. Institute of Applied Physics, Military University of Technology, 2 gen. Kaliskiego St., 00-908 Warsaw, Poland
  2. Vigo Photonics S.A., 129/133 Poznańska St., 05-850 Ożarów Mazowiecki, Poland
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Abstract

In this work, the authors investigated the influence of proton-irradiation on the dark current of XBp longwave infrared InAs/GaSb type-II superlattice barrier detectors, showing a cut-off wavelength from 11 µm to 13 µm at 80 K. The proton irradiations were performed with 63 MeV protons and fluences up to 8∙1011 H+/cm² on a type-II superlattice detector kept at cryogenic (100 K) or room temperature (300 K). The irradiation temperature of the detector is a key parameter influencing the effects of proton irradiation. The dark current density increases due to displacement damage dose effects and this increase is more important when the detector is proton-irradiated at room temperature rather than at cryogenic temperature.
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Authors and Affiliations

Clara Bataillon
1
Jean-Phillipe Perez
1
Rodolphe Alchaar
1
Alain Michez
1
Olivier Gilard
2
Olivier Saint-Pé
3
Philippe Christol
1

  1. University of Montpellier, 163 Auguste Broussonnet St., 34090 Montpellier, France
  2. CNES, 18 Edouard Belin Ave., 31400 Toulouse, France
  3. Airbus Defense & Space, 31 des Cosmonautes St., 31400 Toulouse, France