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Mid-wave InAs/GaSb superlattice barrier infrared detectors with nBnN and pBnN design

Gomółka E., Markowska O., Kopytko M., Kowalewski A., Martyniuk P., Rogalski A., Rutkowski J., Motyka M., Krishna S.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2018

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Vol. 66, nr 3

317--323

EN

We present an investigation of optical and electrical properties of mid-wavelength infrared (MWIR) detectors based on InAs/GaSb strained layer superlattices (SLs) with nBnN and pBnN design. The temperature-dependent behavior of the bandgap was investigated on the basis of absorption measurements. A 50% cut-off wavelength of around 4.5 μm at 80 K and increase of up to 5.6 μm at 290 K was found. Values of Varshni parameters, zero temperature bandgap E0 and empirical coefficients α and β were extracted. Arrhenius plots of dark currents of nBnN and pBnN detectors were compared with the p-i-n design. Dark current density reduction in nBnN and pBnN detectors is observed in comparison to the p-i-n device. This shows a suppression of Shockley-Read-Hall (SRH) processes by means of introducing barrier architecture.

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Barrier infrared detectors

Martyniuk P., Kopytko M., Rogalski A.

Opto-Electronics Review

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2014

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Vol. 22, No. 2

127-146

EN

In 1959, Lawson and co-workers publication triggered development of variable band gap Hg1-xCdxTe (HgCdTe) alloys providing an unprecedented degree of freedom in infrared detector design. Over the five decades, this material system has successfully fought off major challenges from different material systems, but despite that it has more competitors today than ever before. It is interesting however, that none of these competitors can compete in terms of fundamental properties. They may promise to be more manufacturable, but never to provide higher performance or, with the exception of thermal detectors, to operate at higher temperatures. In the last two decades a several new concepts of photodetectors to improve their performance have been proposed including trapping detectors, barrier detectors, unipolar barrier photodiodes, and multistage detectors. This paper describes the present status of infrared barrier detectors. It is especially addressed to the group of III-V compounds including type-II superlattice materials, although HgCdTe barrier detectors are also included. It seems to be clear that certain of these solutions have merged as a real competitions of HgCdTe photodetectors.

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Theoretical modelling of MWIR thermoelectrically cooled nBn HgCdTe detector

Martyniuk P., Rogalski A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2013

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Vol. 61, nr 1

211-220

EN

The paper reports on the medium wavelength infrared (MWIR) unipolar barrier infrared detector (UBIRD) nBn/B-n type (n-type barrier) HgCdTe detector’s photoelectrical performance. The UBIRD nBn/B-n type HgCdTe detector was modelled using commercially available software APSYS. Detailed analysis of the detector’s performance (such as dark current, photocurrent, responsivity, and detectivity) versus bias voltage, operating temperatures, and structural parameters (cap, barrier, and absorber’s doping as well as cap and barrier compositions) were performed pointing out optimal working conditions. Both conduction and valence band alignments of the HgCdTe nBn/B-n type detector structure was simulated stressing their importance on detectors performance. It was shown that higher operation temperature (HOT) conditions achieved by commonly used thermoelectric (TE) coolers allow to obtain detectivities of D* = (3-10)×109 cmHz1/2/W at T = 200 K for detectors with cut-off wavelength of 5.2 ?m The differential resistance area product of RA = 0.15-0.4 cm2 at T = 230 K for bias voltage V = 50 mV was estimated. Finally, the state of the art of UBIRD HgCdTe nBn/B-n type detector performance was compared to InAs/GaSb/B-Al0.2Ga0.8Sb T2SLs nBn detector, InAs/GaSb T2SLs PIN and the HOT HgCdTe bulk photodiodes’ operated at near-room temperature (T = 230 K). It was shown that the RA product of the MWIR UBIRD nBn/B-n type HgCdTe detector can reach a comparable level to the state of the art of the HgCdTe HOT bulk photodiodes and two types of type-II superlattice detectors: PIN photodiodes and nBn detectors.

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Barierowe struktury detekcyjne : nowe możliwości

Martyniuk P., Kowaleski A., Gawron W., Rogalski A.

Elektronika : konstrukcje, technologie, zastosowania

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2012

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Vol. 53, nr 11

102-105

PL

Detektory promieniowania podczerwonego z wąską przerwą energetyczną wymagają chłodzenia celem ograniczenia prądów ciemnych generowanych w strukturze detekcyjnej wśród których najważniejszymi są: procesy generacyjno - rekombinacyjne Shockley-Read-Halla i procesy Augera. Obecnie, zwiekszenie temperatury pracy urządzeń detekcyjnych bez ograniczenia ich osiągów jest głównym celem wielu zespołów badawczych. Procesy generacyjno - rekombinacyjne Augera można ograniczyc poprzez budowę urządzęń detekcyjnych z supersieci II rodzaju (type II superlattice - T2SLs) z związków AIIIBV należących do rodziny 6.1 L. Implementacja barier do struktur detekcyjnych pozwala zredukować niekorzystny wpły procesów Shockley-Read-Halla. Ograniczenie wpływu obu mechanizmów pozwoli zwiększyć temperaturę pracy detektora. Artykuł przedstawia osiągi unipolarnych detektorów nBn z T2SLs InAs/GaSb/B- AI₀.₂Ga₀.₈Sb i HgCdTe oraz ich potencjalne możliwości w rozwoju detektorów promieniowania podczerwonego.

EN

The narrow band gap infrared detectors require cryogenic cooling to suppress dark current, which is typically limited by Shockley-Read-Hall (SRH) and Auger generation-recombination processes. Currently, increasing the operating temperature of the infrared detection systems without sacrificing its performance remains to be a crucial objective of the research groups. Intrinsic Auger thermal generation recombination process could be controlled by implementation of the type II superlattices (T2SLs) AIIIBV 6.1 L family to the detectors architecture while extrinsic SRH process could be suppressed by the barrier's incorporation into detector's structure respectively. Both SHR and Auger suppression lead to increase of the device's operating temperature. The paper reports on the unipolar barrier infrared detector (UBIRD) medium wavelength infrared (MWIR) HgCdTe nBn/B-n type and T2SLs nBn lnAs/GaSb/B-AI₀.₂Ga₀.₈Sb detector's photoelectrical performance and their potential possibilities in the field of infrared detectors development.