PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 13

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  dark current
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available Design and performance of dual-band MWIR/LWIR focal plane arrays based on a type-II superlattice nBn structure
Lee Hyun-Jin, Eom Jun Ho, Jung Hyun Chul, Kang Ko-Ku, Ryu Seong Min, Jang Ahreum, Kim Jong Gi, Kim Young Ho, Jung Han, Kim Sun Ho, Choi Jong Hwa
Opto-Electronics Review
|
2023
|
Vol. 31, Special Issue
art. no. e144560
EN
Dual-band infrared detector, which acquires more image information than single-band detectors, has excellent detection, recognition, and identification capabilities. The dual-band detector can have two bumps to connect with each absorber layer, but it is difficult to implement small pitch focal plane arrays and its fabrication process is complicated. Therefore, the most effective way for a dual-band detector is to acquire each band by biasselectable with one bump. To aim this, a dual-band MWIR/LWIR detector based on an InAs/GaSb type-II superlattice nBn structure was designed and its performance was evaluated in this work. Since two absorber layers were separated by the barrier layer, each band can be detected by bias-selectable with one bump. The fabricated dual-band device exhibited the dark current and spectral response characteristics of MWIR and LWIR bands under negative and positive bias, respectively. Spectral crosstalk that is a major issue in dualband detectors was also improved. Finally, a 20 µm pitch 640 x 512 dual-band detector was fabricated, and both MWIR and LWIR images exhibited an average noise equivalent temperature difference of 30 mK or less at 80 K.
2
Content available The determination of the carriers recombination parameters based on the HOT HgCdTe current-voltage characteristics
Manyk Tetiana, Rutkowski Jarosław, Madejczyk Paweł, Gawron Waldemar, Martyniuk Piotr
Opto-Electronics Review
|
2022
|
Vol. 30, No. 2
art. no. e141596
EN
A theoretical analysis of the mid-wavelength infrared range detectors based on the HgCdTe materials for high operating temperatures is presented. Numerical calculations were compared with the experimental data for HgCdTe heterostructures grown by the MOCVD on the GaAs substrates. Theoretical modelling was performed by the commercial platform SimuAPSYS (Crosslight). SimuAPSYS fully supports numerical simulations and helps understand the mechanisms occurring in the detector structures. Theoretical estimates were compared with the dark current density experimental data at the selected characteristic temperatures: 230 K and 300 K. The proper agreement between theoretical and experimental data was reached by changing Auger-1 and Auger-7 recombination rates and Shockley-Read-Hall carrier lifetime. The level of the match was confirmed by a theoretical evaluation of the current responsivity and zero-bias dynamic resistance area product (R0A) of the tested detectors.
3
Content available remote Nanostructures with Ge–Si quantum dots for infrared photodetectors
Izhnin I. I., Fitsych O. I., Voitsekhovskii A. V., Kokhanenko A. P., Lozovoy K. A., Dirko V. V.
Opto-Electronics Review
|
2018
|
Vol. 26, No. 3
195--200
EN
In this paper questions of optimization of growth conditions in the method of molecular beam epitaxy for creation of high-efficient quantum dot infrared photodetectors are considered. As a model material system for theoretical investigations, heterostructures with germanium-silicon quantum dots on the silicon surface are chosen. For calculations of the dependencies of quantum dots array parameters on synthesis conditions the kinetic model of growth of differently shaped quantum dots based on the general nucleation theory is proposed. The theory is improved by taking into account the change in free energy of nucleation of an island due to the formation of additional edges of islands and due to the dependence of surface energies of facets of quantum dots on the thickness of a 2D wetting layer during the Stranski–Krastanow growth. Calculations of noise and signal characteristics of infrared photodetectors based on heterostructures with quantum dots of germanium on silicon are done. Dark current in such structures caused by thermal emission and barrier tunneling of carriers, as well as detectivity of the photodetector in the approximation of limitation by generation-recombination noises are estimated. Moreover, the presence of dispersion of quantum dots by size is taken into account in the calculations of the generation-recombination noises. Results of calculations of the properties of structures with quantum dots and their dependencies on growth parameters, as well as the characteristics of quantum dot photodetectors are presented. Comparison of the estimated parameters of quantum dots ensembles and the characteristics of quantum dot photodetectors with experimental data is carried out.
4
Content available remote Analysis of triple metal surrounding gate (TM-SG) III–V nanowire MOSFET for photosensing application
Sharma S. K., Jain A., Raj B.
Opto-Electronics Review
|
2018
|
Vol. 26, No. 2
141--148
EN
In this paper, a low power highly sensitive Triple Metal Surrounding Gate (TM-SG) Nanowire MOSFET photosensor is proposed which uses triple metal gates for controlling short channel effects and III–V compound as the channel material for effective photonic absorption. Most of the conventional FET based photosensors that are available use threshold voltage as the parameter for sensitivity comparison but in this proposed sensor on being exposed to light there is a substantial increase in conductance of the GaAs channel underneath and, thereby change in the subthreshold current under exposure is used as a sensitivity parameter (i.e., Iillumination/IDark). In order to further enhance the device performance it is coated with a shell of AlxGa1-x As which effectively passivates the GaAs surface and provides a better carrier confinement at the interface results in an increased photoabsorption. At last performance parameters of TM-SG Bare GaAs Nanowire MOSFET are compared with TM-SG core-shell GaAs/AlGaAs Nanowire MOSFET and the results show that Core-Shell structures can be a better choice for photodetection in visible region.
5
Content available remote Influence of doping on the performance of GaAs/AlGaAs QWIP for long wavelength applications
Billaha A., Das M. K.
Opto-Electronics Review
|
2016
|
Vol. 24, No. 1
25--33
EN
Effect of doping and other device parameters on inter sub−band transition in the well, responsivity and dark current of GaAs/AlxGa1-xAs quantum well infrared photodetector (QWIP) is investigated using theoretical model. 2X2 Hamiltonian method is used to calculate Eigen energy states in this modelling. Results show that peak absorption, responsivity and spectral broadening width increase nonlinearly with increasing doping concentration in the well. Peak absorption coefficient increases with increase in well width also. Moreover, with increase in mole fraction of Al in AlxGa1-xAs barrier, the inter sub-band absorption is enhanced but, peak wavelength of absorption shifts towards shorter wavelengths. Dark current density depends on both, the doping concentration and applied bias.
6
Content available A review of dark current nonlinearities in CCD image sensors
Popowicz A.
Pomiary Automatyka Kontrola
|
2014
|
R. 60, nr 6
362--365
EN
Charge coupled devices are the image sensors extensively used in scientific imaging. One of the problems of low light imaging is the collection of additional thermal charge during the exposure. In the paper the results and conclusions of 4-year research on dark current abnormalities are presented. Their sources and possible explanation for the observed phenomena are investigated. The dark current unique behavior should be taken into account especially while imaging in extremely low light level conditions.
PL
Matryce CCD są czujnikami wykorzystywanymi do rejestracji obrazów. Ze względu na pełne wykorzystanie powierzchni światłoczułej są one wykorzystywane, gdy ilość padającego światła jest bardzo niska. Do takich zastosowań należy m.in. obrazowanie w astronomii, gdzie czasy naświetlania pojedynczego zdjęcia sięgają wielu minut. Jednym z problemów przy tego typu zastosowaniach jest obecność prądu ciemnego, który wnosi do obrazu składową addytywną zależną od temperatury czujnika. W celu wyeliminowania tych zjawisk temperaturę matrycy CCD stabilizuje się wykorzystując m.in. ogniwa Peltiera oraz wykonuje się tzw. klatki ciemne (zdjęcia bez dostępu światła), aby następnie odjąć je od otrzymanego obrazu. Taka technika korekcji zakłada, że procesy termiczne przebiegają w sposób stały oraz, że są one niezależne od oświetlania matrycy. W artykule przedstawiono trzy typy nieliniowości prądu ciemnego, dla których powyższe założenia nie są spełnione. Pierwszy typ powiązano ze specyficznym położeniem defektu generującego ładunek termiczny, natomiast drugi typ skojarzono z obecnością defektów strukturalnych - dyslokacji. Trzecim rodzajem opisywanych zjawisk są losowe skoki tempa generacji termicznej. Wiedza o problemach prądu ciemnego jest kluczowa w przypadku dokonywania korekcji naukowych zdjęć źródeł emitujących niewielką ilość światła. Uwzględnienie odmiennych zachowań generacji termicznej pozwala na poprawę jakości skorygowanych obrazów.
7
Content available remote Optical identification of crystal defects in CCD matrix
Popowicz A.
Przegląd Elektrotechniczny
|
2013
|
R. 89, nr 3a
79--82
PL
Celem artykułu jest zaprezentowanie oryginalnego pomysłu identyfikacji typów defektów struktury krystalicznej czujników światła jakimi są matryce CCD. Procedura jest nieskomplikowana i możliwa do przeprowadzenia bez specjalistycznej i drogiej aparatury. Metoda ta umożliwia rozróżnienie defektów na: punktowe oraz defekty przestrzenne – dyslokacje. Podczas badań wykazano również, iż typ defektu wpływa na zachowanie generacji prądu ciemnego podczas rejestracji światła.
EN
An original idea of semiconductor defects identification in CCD matrix was presented in the article. The procedure is simple and easy to execute because of no need for special and expensive equipment. The method classifies defects into two groups: the point defects and the spatial defects (dislocations). During the experiments it was proven that the type of defect affects the behavior of the dark current generation during the light gathering .
8
Analysis of temperature dependence of dark current mechanisms in MWIR type-II superlattice photodiodes
Wróbel J., Madejczyk P., Gawron W., Rogalski A.
Elektronika : konstrukcje, technologie, zastosowania
|
2013
|
Vol. 54, nr 9
113-116
EN
We report on temperature dependence characteristics of mid wavelength InAs/GaSb type-II superlattice photodiodes in a temperature range from 120 K to 240 K. A bulk based model with an effective bandgap of superlattice material has been used in modelling of the experimental data. Temperature and bias dependent differential resistances have been analyzed in detail due to contributing mechanisms that limit the electrical performance of the diodes. C1-HH1 reduced mass was estimated from the fitting to the high reverse bias (< - 1.0 V) voltage, and given about 0.015 m0 in the whole considered temperature range. This value agree well with much more complex simulations and cyclotron resonance measurements. Obtaining so good results was possible thanks to including series resistance into calculations.
PL
W pracy przedstawiono analizę charakterystyk prądowo-napięciowych oraz rezystancji dynamicznych fotodiod PIN z supersieci II typu InAs10ML/ GaSb10ML zakresu średniej podczerwieni. Rozważania teoretyczne transportu nośników przeprowadzono stosując teorię Shockley’a złącza wykonanego w materiale objętościowym. W zakresie temperatur 120 - 240 K zaobserwowano kilka mechanizmów składowych prądu ciemnego, w tym: mechanizm dyfuzyjny i generacyjno-rekombinacyjny, dwa mechanizmy tunelowania, oraz upływność powierzchniową. W obliczeniach uwzględniono również wpływ rezystancji szeregowej, który szczególnie w zakresie temperatur osiąganych przez chłodziarki termoelektryczne (T > 180 K), okazał się znaczący. Wybrane parametry dopasowujące uzyskane z analitycznych zależności na składowe prądu ciemnego (w tym masę zredukowaną przejścia C1-HH1) zostały porównane z dostępnymi literaturowymi danymi eksperymentalnymi.
9
Content available remote A study on temperature characteristics of green silicon photodetector
Fu X., Yao S., Tao G., De M.
Optica Applicata
|
2010
|
Vol. 40, nr 4
935--941
EN
Green silicon photodetector is successfully developed on the substrate of n-type single-crystal (100) silicon. To improve its performance, the detector is optimized by optimizing the p-n junction depth xj and the thickness of antireflection layer to reduce dark current, shorten response time and increase sensitivity. The spectrum response SNR can be over 104 within the wavelength range of 500-600 nm and the peak of spectral responsivity is 0.48 A/W at about 520 nm. The temperature characteristics of the dark current at reverse bias and photocurrent at zero bias are emphatically investigated. Firstly, the temperature behavior of dark current at 10 V reverse bias voltage and temperature range of 253-323 K is studied. Results show that dark current is dominated by generation-recombination current Igr the temperature range of 253-283 K and it is dominated by traps tunneling current Itt at the temperature range of 283-323 K. Secondly, the temperature behavior of photocurrent at zero bias and temperature range of 213-353 K is discussed. Results show that photocurrent increases as temperature increases below room temperature and almost holds the line over room temperature. Consequently, photodetector fulfils quality requirements.
10
Content available remote Insight into performance of quantum dot infrared photodetectors
Martyniuk P., Rogalski A.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2009
|
Vol. 57, nr 1
103-116
EN
In the paper, an algorithm for theoretical evaluation of dark and illumination characteristics of quantum dot infrared photodetectors (QDIPs) is presented. The developed algorithm is based on a model previously published by Ryzhii and co-workers. In our considerations it is assumed that both thermionic emission and field-assisted tunnelling mechanisms determine the dark current of quantum dot detectors. The model permits to calculate the dark current, current gain, average number of electrons in quantum dots, photocurrent, and detector responsivity as a function of the structural parameters. Moreover, it explains some features of QDIP characteristics. In several cases, the theoretical predictions are compared with experimental data. Good agreement between both kinds of data has been obtained.
11
Badanie wpływu technologii na parametry wybranych elementów optoelektronicznych
Zborowska-Lindert I., Boratyński B., Paszkiewicz B., Ohly T.
Elektronika : konstrukcje, technologie, zastosowania
|
2004
|
Vol. 45, nr 10
41-43
PL
Przedstawiono wyniki badań związanych z konstrukcją i wytwarzaniem fotodetektorów MSM oraz mikrobaterii fotowoltaicznych ze związków Ga(Al,In)As. W prawidłowej konstrukcji obydwu grup przyrządów, niezwykle istotna jest minimalizacja prądu ciemnego i upływności elementów. Opisano efekty pasywacji powierzchni fotodetektorów poprzez zastosowanie warstw dielektrycznych Si3NOx i AIN. Badano także wpływ konpozycji materiału warstwy aktywnej mikrobaterii fotowoltaicznej na jej prąd zwarciowy i napięcie rozwarcia.
EN
Influence of process technology on electrical parameters of Ga(Al,In)As MSM photodetectors and photovoltaic micro-arrays was envestigated. The effects of the dark current suppression due to surface passivation in MSM photodetectors with AIN and Si3NOx layers are presented. The photovoltaic arrays were fabricated as a series connection of seven Ga((Al,In)As PIN diodes. The influence of device active layer composition on the open circuit voltage and the short circuit current values was investigated.
12
Content available remote Quantum dot infrared photodetector
Liu H. C.
Opto-Electronics Review
|
2003
|
Vol. 11, No. 1
1-5
EN
This paper discusses key issues related to the quantum dot infrared photodetector (QDIP). These are the normal incidence response, the dark current, and the responsivity and detectivity. We attempt to address the following questions of what is QDIP' s potential, what is lacking, and what is needed to make the device interesing for practical applications. It is argued that so for the present QDIP devices have not fully demonstrated the potential advantages. Representative experimental results are compared with characteristics of quantum well infrared photodetectors. Areas that need improvements are pointed out.
13
Content available remote Sharp infrared eyes: the journey of QWIPs from concept to large inexpensive sensitive arrays in hand-held infrared cameras
Gunapala S., Bandara S., Liu J., Sundaram M.
Opto-Electronics Review
|
1999
|
Vol. 7, No. 4
271-282
EN
Arguably one of the simplest device realizations of the classic particle-in-a-box problem of basic quantum mechanics is the Quantum Well Infrared Photodetector (QWIP). Optimization of the detector design and material growth and processing has culminated in the realization of a portable infrared camera with a large (256 x 256 pixel ) focal plane array of QWIPs which can see at 8.5 um, holding forth great promise for a variety of applications in the 8-14 um wavelength range. In this paper we discuss the physics and technology of the QWIP and report on the performance of the world's first hand-held infrared camera at these long wavelengths.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.