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Długofalowe detektory podczerwieni dla telekomunikacji optycznej w otwartej przestrzeni

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Gawron W. , Gutowska M. , Pędzińska M. , Pawluczyk J. , Piotrowski J.

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2010

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tom Vol. 51, nr 10

76-79

PL

Praca pokazuje zasady projektowania i właściwości detektorów podczerwieni dla szerokopasmowych modułów detekcyjnych przeznaczonych dla otwartych łączy optoelektronicznych. Są to heterostrukturalne fotodetektory długofalowego (8...12 µm) promieniowania podczerwonego pracujące bez chłodzenia kriogenicznego. Podstawą konstrukcji fotodetektorów są złożone heterostruktury HgCdTe wytwarzane metodą MOCVD.

EN

Long wavelength infrared photodetectors from HgCdTe for the second generation free-space optical links are reported. The photodetectors are based on optically immersed photodiodes operating with Peltier coolers. The photodiodes are based on HgCdTe heterostructure. The devices have been grown using Metalorganic Chemical Vapor Deposition (MOCVD).

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Heterostruktury w niechłodzonych detektorach podczerwieni

86%

Gawron W. , Rogalski A. , Madejczyk P. , Pawluczyk J. , Piotrowski J. , Piotrowska A.

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2010

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tom Vol. 51, nr 10

106-109

PL

Niechłodzone detektory podczerwieni z HgCdTe to jeden z niewielu produktów optoelektronicznych produkowanych obecnie w Polsce i eksportowanych do wielu krajów świata. Przyrządy te znajdują zastosowania praktyczne w nowoczesnej aparaturze naukowej i medycznej, w przemyśle, ochronie środowiska naturalnego, technice wojskowej. Artykuł prezentuje obecny stan rozwoju niechłodzonych detektorów podczerwieni w Polsce.

EN

Uncooled infrared photodetectors from HgCdTe are one of few optoelectronic products manufactured currently in Poland and exported to many countries worldwide. The devices have found important applications for scientific and medical instruments, in industry, environment protection, and military technique. The paper presents the state-of-art in the field of uncooled photodetectors from HgCdTe in Poland.

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Moduły detekcyjne dla telekomunikacji optycznej w otwartej przestrzeni drugiej generacji

86%

Bielecki Z. , Brudnowski M. , Gawron M. , Pawluczyk J. , Piotrowski A. , Piotrowski J.

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tom Vol. 49, nr 7-8

95-100

PL

Przedstawiono konstrukcję i właściwości szerokopasmowych modułów detekcyjnych przeznaczonych dla otwartych łączy optoelektronicznych drugiej generacji. W modułach tych wykorzystano heterostrukturalne fotodetektory długofalowego (λ ≈ 10 μm) promieniowania podczerwonego, pracujące w temperaturze otoczenia lub chłodzone za pomocą chłodziarek termoelektrycznych. Podstawą konstrukcji fotodetektorów są złożone heterostruktury HgCdTe wytwarzane metodą MOCVD. Dzięki optymalizacji konstrukcji moduły detekcyjne osiągają wykrywalności >1010cmHz1/2/W i stałe czasowe <0,1 ns.

EN

Wide bandwidth IR detector packages for the second generation freespace optical links are reported. The packages are based on long wavelength HgCdTe photodetectors operating at ambient temperatures or cooled with Peltier coolers. Due to advanced architecture the devices are characterized by >1010cmHz1/2/W detectivities and <0.1 ns time constants.

4

Uncooled MWIR and LWIR photodetectors in Poland

86%

Piotrowski J. , Pawluczyk J. , Piotrowski A. , Gawron W. , Romanis M. , Kłos K.

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tom Vol. 18, No. 3

318-327

EN

The history, status, and recent progress in the middle and long wavelength Hg1-xCdxTe infrared detectors operating at near room temperatures are reviewed. Thermal generation of charge carriers in narrow gap semiconductor is a major limitation or sensitivity. Cooling is a straightforward way to suppress thermal generation of charge carriers and reduce related noise. However, at the same time, cooling requirements make infrared systems bulky, heavy, and inconvenient in use. A number of concepts to improve performance of photodetectors operating at near room temperatures have been proposed and implemented. Recent considerations of the fundamental detector mechanisms suggest that near perfect detection can be achieved without the need for cryogenic cooling. This paper, to a large degree, is based on the research, development, and commercialization of uncooled HgCdTe detectors in Poland. The devices have been based on 3D-variable band gap and doping level structures that integrate optical, detection and electric functions in a monolithic chip. The device architecture is optimized for the best compromise between requirements of high quantum efficiency, efficient and fast collection of photogenerated charge carriers, minimized thermal generation, reduced parasitic impedances, wide linear range, wide acceptance angles and other device features. Recent refinements in the devices design and technology have lead to sensitivities close to the background radiation noise limit, extension of useful spectral range to > 16 µm wavelength and picosecond range response times. The devices have found numerous applications in various optoelectronic systems. Among them there are fast scan FTIR spectrometers developed under MEMFIS project.

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Growth and properties of MOCVD HgCdTe epilayers on GaAs substrates

72%

Madejczyk P. , Piotrowski A. , Gawron W. , Kłos K. , Pawluczyk J. , Rutkowski J. , Piotrowski J. , Rogalski A.

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2005

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tom Vol. 13, No. 3

239-251

EN

Growth of MOCVD Hg1-xCdxTe (HgCdTe) epilayers on GaAs substrates is described. The paper focuses on the interdiffused multilayer process (IMP). In this process, the CdTe/HgTe growth times are comparable with transition times between the phases. The non-optimum flow velocities and partial pressures that may induce poor morphology and reduce growth rate characterize the growth during transition stages. The optimum conditions for the growth of single layers and complex multilayer heterostructures have been established. One of the crucial stages of HgCdTe epitaxy is CdTe nucleation on GaAs substrate. Successful composite substrates have been obtained with suitable substrate preparation, liner and susceptor treatment, proper control of background fluxes and appropriate nucleation conditions. Due to the large mismatch between GaAs and CdTe, both (100) and (111) growth may occur. It mostly depends on substrate disorientation and preparation, nucleation conditions and growth temperature. Cd or Te substrate treatment just before growth results in (100) and (111) orientation, respectively. Generally, layers with orientation (100) show superior morphology compared to (111) but they are also characterized by hillocks. The benefits of the precursors ethyl iodine (EI) and arsine (AsH3) for controlled iodine donor doping and arsenic acceptor doping are summarized. Suitable growth conditions and post growth anneal is essential for stable and reproducible doping. In-situ anneal seems to be sufficient for iodine doping at any required level. In contrast, efficient As doping with near 100% activation requires ex-situ anneal at near saturated mercury vapours. The transport properties of HgCdTe epilayers indicate on achieving device quality material. Reproducible n- and p-type doping at the low, intermediate and high level (1015-1018 cm-3) has been achieved with stable iodine and arsenic dopants. The mobilities and carrier lifetimes achieved for extrinsically doped n-type and p-type layers follow essentially the same trends observed in state-of-the-art liquid phase epitaxy grown HgCdTe.

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Status of long-wave Auger suppressed HgCdTe detectors operating > 200 K

72%

Martyniuk P. , Gawron W. , Stępień D. , Pawluczyk J. , Kębłowski A. , Madejczyk P. , Kopytko M. , Koźniewski A.

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tom Vol. 23, No. 4

278-286

EN

We report on the status of long-wave infrared Auger suppressed HgCdTe multilayer structures grown on GaAs substrates designed for high operating temperature condition: 200-300 K exhibiting, detectivity ~10¹¹ cmHz¹/² /W, time response within a ~120 ps range at 230 K. Abnormal responsivity within the range of ~30 A/W for electrical area 30×30 μm² under reverse bias V = 150 mV is reported. Maximum extraction coefficient of ~2.3 was estimated for analysed structures.

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Growth of MOCVD HgCdTe heterostructures for uncooled infrared photodetectors

72%

Piotrowski A. , Madejczyk P. , Gawron W. , Kłos K. , Pawluczyk J. , Grudzień M. , Piotrowski J. , Rogalski A.

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8

Growth of MOCVD HgCdTe heterostructures for uncooled infrared photodetectors

72%

Piotrowski A. , Madejczyk P. , Gawron W. , Kłos K. , Pawluczyk J. , Grudzień M. , Piotrowski J. , Rogalski A.

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tom Vol. 53, nr 2

139-149

EN

In the paper recent progress at VIGO/MUT (Military University of Technology) MOCVD Laboratory in the growth of Hg1-xCdx Te (HgCdTe) multilayer heterostructures on GaAs/CdTe substrates is presented. The optimum conditions for the growth of single layers and complex multilayer heterostructures have been established. One of the crucial stages of HgCdTe epitaxy is CdTe nucleation on GaAs substrate. Successful composite substrates have been obtained with suitable substrate preparation, liner and susceptor treatment, proper control of background fluxes and appropriate nucleation conditions. The other critical stage is the interdiffused multilayer process (IMP). The growth of device-quality HgCdTe heterostructures requires complete homogenization of CdTe-HgTe pairs preserving at the same time suitable sharpness of composition and doping profiles. This requires for IMP pairs to be very thin and grown in a short time. Arsenic and iodine have been used for acceptor and donor doping. Suitable growth conditions and post growth anneal is essential for stable and reproducible doping. In situ anneal seems to be sufficient for iodine doping at any required level. In contrast, efficient As doping with near 100% activation requires ex situ anneal at near saturated mercury vapours. As a result we are able to grow multilayer fully doped (100) and (111) heterostructures for various infrared devices including photoconductors, photo electromagnetic and photovoltaic detectors. The present generation of uncooled long wavelength infrared devices is based on multijunction photovoltaic devices. The technology steps in fabrication of devices are described. It is shown that near-BLIP performance is possible to achieve at c.a 230 K with optical immersion. These devices are especially promising as 7.8-9.5-J-[mu]m detectors, indicating the potential for achieving detectivities above 10 do potęgi 9 cmHz1/2/W.