Wyniki wyszukiwania - Biblioteka Nauki

1

Fast Response Hot (111) HGCDTE MWIR Detectors

100%

Grodecki K. , Martyniuk P. , Kopytko M. , Kowalewski A. , Stępień D. , Kębłowski A. , Piotrowski A. , Piotrowski J. , Gawron W. , Rogalski A.

Metrology and Measurement Systems

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2017

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tom Vol. 24, nr 3

509--514

EN

In this work we report simulation and experimental results for an MWIR HgCdTe photodetector designed by computer simulation and fabricated in a joint laboratory run by VIGO Sytems S.A. and Military University of Technology. The device is based on a modified N+pP+ heterostructure grown on 2”., epiready, semi-insulating (100) GaAs substrates in a horizontal MOCVD AIX 200 reactor. The devices were examined by measurements of spectral and time responses as a function of a bias voltage and operating temperatures. The time response was measured with an Optical Parametric Oscillator (OPO) as the source of ~25 ps pulses of infrared radiation, tuneable in a 1.55–16 μm spectral range. Two-stage Peltier cooled devices (230 K) with a 4.1 μm cut-off wavelength were characterized by 1.6 × 1012 cm Hz1/2/W peak detectivity and < 1 ns time constant for V > 500 mV.

2

Design of a measurement stand with DAQ card and semiconductor laser for recording acoustic signals

100%

Krawiecki Z. , Gloger D.

Computer Applications in Electrical Engineering

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2014

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tom Vol. 12

541--550

EN

This article describes the stage of work associated with the implementation of a program- controlled measuring stand for recording the acoustic signals. An attempt has been made for practical implementation of the stand that uses light from a semiconductor laser, modulated by acoustic wave to obtain the information transmitted by this wave. The authors decided to build the hardware construction of the stand with the use of: a PC which serves as the controller, a DAQ card, the light emitter set with a semiconductor laser and the light receiving set capable of processing the received signal into a form suitable for a DAQ card. Moreover, additional equipment used during the examination tests is also described. The software part of the stand includes: device drivers and an application written in LabVIEW environment. The functions of signal processing and analysis, graphical and numerical presentation of the data, recording to file and reading the stored data from a file are all implemented in the application. The achieved stage of a work has been confirmed by sample measurements.

3

Detektory promieniowania ultrafioletowego z GaN i AlGaN

100%

Zynek J.

Materiały Elektroniczne

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2001

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tom T. 29, nr 3-4

20-35

PL

Artykuł zawiera opis stosowanych obecnie konstrukcji i technologii fotodetektorów z GaN i AlGaN przeznaczonych do detekcji promieniowania ultrafioletowego oraz analizę wpływu parametrów fizycznych warstw epitaksjalnych GaN i AlGaN na właściwości tych fotodetektorów. Analiza dotyczy fotorezystorów, fotodetektorów z barierą Schottky'ego i fotodiod p-i-n. Omówiono uzyskane dotychczas charakterystyki elektryczne i fotoelektryczne tych przyrządów.

EN

The design and technology of ultraviolet photodetectors made of GaN and AlGaN have been reviewed. The influence of physical parameters of GaN and AlGaN epitaxial layers on properties of these photodetectors has been analyzed. Presented analysis concerns photoconductors, Schottky barrier photodetectors and p-i-n photodiodes. The performance of these devices is described in detail.

4

Wybrane właściwości optyczne detektora fotometrycznego BPYP 07

100%

Fryc I.

Zeszyty Naukowe Politechniki Białostockiej. Matematyka, Fizyka, Chemia

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1999

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tom Z. 19

113-119

PL

W pracy omówiono podstawowe parametry optyczne krzemowych fotoogniw pomiarowych. Przedstawiono także metody badania jakości przetworników oraz wyniki pomiarów dla przykładowo wybranego fotoogniwa BPYP 07.

EN

In the paper of the basic parameters of measuring photovoltaic cell BPYP 07 discused. The method of testing the quality of the cell and the results of measurement made on the silicon cell are given.

5

Design and properties of silicon avalanche photodiodes

100%

Węgrzecka I. , Węgrzecki M. , Grynglas M. , Bar J. , Uszyński A. , Grodecki R. , Grabiec P. , Krzemiński S. , Budzyński T.

Opto-Electronics Review

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2004

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tom Vol. 12, No. 1

95-104

EN

A family of silicon avalanche photodiodes with an n⁺-p -π-p⁺ epiplanar structure was developed at the Institute of Electron Technology (ITE). The diameters of photosensitive area range from 0.3 mm to 5 mm. These photodiodes are optimised for detection of 800–850 nm radiation and in that range achieve excellent parameters – high gain, low noise, high detectivity. The detailed research on their spectral dependencies of the gain and noise parameters has revealed that their range of operating is considerable wider and stretches from 550 to 1000 nm. The principles of operation and design considerations concerning avalanche photodiodes are outlined in this paper. Next, the design, technology and properties of silicon avalanche photodiodes developed at the ITE are discussed. Avalanche photodiodes are widely used in detection of very weak and very fast optical signals. Presently in the world, the studies are carried out on applying the avalanche photodiodes in detection of X radiation and in the scintillation detection of nuclear radiation.

6

AIII-BV(N) photodetectors with functionally graded active area

100%

Wośko M. , Paszkiewicz B. , Piasecki T. , Prażmowska J. , Paszkiewicz R. , Tłaczała M.

Optica Applicata

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2007

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tom Vol. 37, nr 1-2

161-165

EN

Functionally graded materials (FGM) find widespread for mechanical applications. Nowadays, they become more and more attractive in fabrication of electronic and optoelectronic devices. This is due to by their unique properties. FGM are potential candidates for high sensitive photonic devices which could operate in a wide spectral range (also for voltage tunable photodetectors). In this paper, the analysis of several photodetector constructions fabricated in FGM has been presented. The influence of AIII-BV(N) grading layers composition and configuration of the detector on its optical and electrical properties has been discussed. Also, a comparison between conventional non-graded and graded devices has been made. All simulations presented in the work are performed by the specialized software designed for modeling AIII-BV(N) graded structures. The software allow us to calculate both the parameters of FGM structure and device characteristics. During the simulation process it was noticed that the bandgap gradation in phototodetector active area improved its sensitivity up to 150% compared to classical, non-graded structures. Also, another effect such the wavelength sensitivity observed in these devices makes them very attractive for applications in which the high sensitive wavelength dependence is a key factor.

7

A(III)B(V) detectors with graded active region

100%

Wośko M. , Paszkiewicz B. , Szyszka A. , Macherzyński W. , Radziewicz D. , Ściana B. , Paszkiewicz R. , Tłaczała M. , Sęk G. , Poloczek P. , Motyka M. , Misiewicz J.

Materials Science Poland

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2008

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tom Vol. 26, No. 1

87--94

EN

Results of modelling and fabrication of photodetectors with composition graded active layers have been presented. Simulated and measured spectral characteristics of the proposed detectors have been shown. Advantages of such structures have been discussed with respect to conventional detectors with non-graded active areas as well as some technological problems of compositionally graded semiconductor layers.

8

Comparison studies of infrared photodetectors with a quantum-dot and a quantum-wire base

100%

El-Tokhy M. S. , Mahmound I. I. , Konber H. A.

Opto-Electronics Review

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2011

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tom Vol. 19, No. 4

405-417

EN

This paper mainly presents a theoretical analysis for the characteristics of quantum dot infrared photodetectors (QDIPs) and quantum wire infrared photodetectors (QRIPs). The paper introduces a unique mathematical model of solving Poisson's equations with the usage of Lambert W functions for infrared detectors' structures based on quantum effects. Even though QRIPs and QDIPs have been the subject of extensive researches and development during the past decade, it is still essential to implement theoretical models allowing to estimate the ultimate performance of those detectors such as photocurrent and its figure-of-merit detectivity vs. various parameter conditions such as applied voltage, number of quantum wire layers, quantum dot layers, lateral characteristic size, doping density, operation temperature, and structural parameters of the quantum dots (QDs), and quantum wires (QRs). A comparison is made between the computed results of the implemented models and fine agreements are observed. It is concluded from the obtained results that the total detectivity of QDIPs can be significantly lower than that in the QRIPs and main features of the QRIPs such as large gap between the induced photocurrent and dark current of QRIP which allows for overcoming the problems in the QDIPs. This confirms what is evaluated before in the literature. It is evident that by increasing the QD/QR absorption volume in QDIPs/QRIPs as well as by separating the dark current and photocurrents, the specific detectivity can be improved and consequently the devices can operate at higher temperatures. It is an interesting result and it may be benefit to the development of QDIP and QRIP for infrared sensing applications.

9

Two-dimensional modeling of surface photovoltage in metal/insulator/n-GaN structure with cylindrical symmetry

88%

Matys M. , Powroznik P. , Powroznik P. , Kupka D. , Adamowicz B.

Optica Applicata

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2013

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tom Vol. 43, nr 1

47--52

EN

The rigorous numerical analysis of the surface photovoltage (SPV) versus excitation UV-light intensity (Φ), from 104 to 1020 photon/(cm2s) in a metal/insulator/n-GaN structure with a negative gate voltage (VG = –2 V) was performed using a finite element method. In the simulations we assumed a continuous U-shape density distribution function Dit(E) of the interface states and n-type doping concentration ND = 1016 cm–3. The SPV signal was calculated and compared in three different characteristic regions at the interface, namely i) under the gate centre, ii) near the gate edge and iii) between the gate and ohmic contact. We attributed the differences in SPV(Φ) dependences to the influence of the interface states in terms of the initial band bending and interface recombination controlled by the gate bias. The obtained results are useful for the design of GaN-based UV-radiation photodetectors.

10

Design and fabrication of GaSb/InGaAsSb/AlGaSb mid-infrared photodetectors

88%

Piotrowski T. T. , Piotrowska A. , Kamińska E. , Piskorski M. , Papis E. , Gołaszewska K. , Kątcki J. , Ratajczak J. , Adamczewska J. , Wawro A. , Piotrowski J. , Orman Z. , Pawluczyk J. , Nowak Z.

Opto-Electronics Review

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2001

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tom Vol. 9, No. 2

188-194

EN

The paper reports on the design and fabrication of LPE-grown GaSb/n-InxGa₁-xAsySb₁-y/p-AlxGa₁-xAsySb₁-y heterojuction photodetectors operating in the 2-2.4 mm wavelength region. Experiments on LPE growth of high-x-content quaternaries as well as optimisation of device processing has been carried out. LPE growth at T » 530°C enabled obtaining lattice matched heterostructures with 19% indium in the active layer In₀.₁₉Ga₀.₈₁As₀.₁₆Sb₀.₈₄/Al₀.₂₄Ga₀.₇₆As₀.₀₄Sb₀.₉₆ and photodetectors with lc = 2.25 um. By increasing the temperature of epitaxial growth to 590°C In₀.₂₃Ga₀.₇₇As₀.₁₈Sb₀.₈₂/Al₀.₃₀Ga₀.₇₀As₀.₀₃Sb₀.₉₇ heterostructures (with 23% indium content) suitable for photodetectors with lc = 2.35 um have been obtained. Mesa-type photodiodes were fabricated by RIE in CCl₄/H₂ plasma and passivated electrochemically in (NH₄)₂S. These devices are characterised by differential resistance area product up to 400 Wcm² and the detectivity in the range the range 3´1010-2´1011 cmHz¹/²/W, in dependence on the photodiode active area and cut-off wavelength.

11

Direct characterisation of AM-to-PM phenomena in fast Si and InGaAs photodiodes

88%

Budzyn G. , Barański J.

Opto-Electronics Review

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2024

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tom Vol. 32, No. 4

art. no. e152678

EN

The direct measurement method of AM-to-PM phenomena in fast silicon and InGaAs photodiodes is described. The setup is simple, relatively inexpensive and allows fast and precise measurements not only in a laboratory environment. During sample tests, the authors have found that the influence of bias voltage on the phase shift of an optical signal conversion is significant. The reported effect together with the influence of modulation depth on phase shift (AM-to-PM conversion) has a negative impact on an optical signal reception especially in coherent applications. The authors show that, with our proposed setups, it is possible to find optimal bias voltage and optimal optical power in order to reduce electrical phase noise of the photodetector.

12

Wpływ kąta padania światła na wartości natężenia oświetlenia zmierzone za pomocą czujników fotometrycznych

88%

Krac E. , Górecki K.

Przegląd Elektrotechniczny

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2021

|

tom R. 97, nr 12

212--215

PL

W pracy przedstawiono wyniki badań wpływu kąta padania światła na wartości natężenia oświetlenia zmierzone przy wykorzystaniu wybranych czujników fotometrycznych. Opisano stanowisko pomiarowe oraz zaprezentowano i przedyskutowano uzyskane wyniki pomiarów. Zbadano również wpływ osłon korygujących montowanych na fotodetektorach na zmierzone wartości natężenia oświetlenia.

EN

The paper presents the results of research on the influence of the angle of incidence of light on the values of illuminance measured with the use of selected sensors with photodetectors. The measurement set-up is described and the obtained measurement results are presented and discussed. The influence of the corrective shields mounted on the photodetectors on the measured values of the illuminance is also investigated.

13

Półprzewodnikowe detektory promieniowania z optyczną mikrownęką rezonansową

75%

Muszalski J. , Kaniewski J.

Elektronika : konstrukcje, technologie, zastosowania

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2004

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tom Vol. 45, nr 5

42-46

PL

Fotodetektory z mikrownęką rezonansową są szczególnie przydatne w zastosowaniach, gdzie wymagana jest duża prędkość działania, jak np. we współczesnych systemach telekomunikacyjnych. W detektorach tych duża szybkość działania przy jednocześnie dużej sprawności kwantowej osiągnięta jest dzięki umieszczeniu obszaru aktywnego wewnątrz optycznej wnęki rezonansowej. W niniejszej pracy omówiony jest fotodetektor z mikrownęką rezonansową zaprojektowany na pasmo 1550 nm.

EN

Resonat cavity enhanced photo-detectors are promising candidates for application in high-speed optical communication and interconnections. In these photo-detectors both high bandwidth and high quantum efficiency can be achieved simultaneously due to standing wave formation in the resonant optical cavity. In this paper a state-of-the-art photo-detector designed for 1550 nm is presented.

14

Quantum dot infrared photodetector

75%

Liu H. C.

Opto-Electronics Review

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2003

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tom 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.

15

Błędy korekcji kątowej głowicy fotometrycznej luksomierza

75%

Fryc I.

Zeszyty Naukowe Politechniki Białostockiej. Matematyka, Fizyka, Chemia

|

1999

|

tom Z. 19

105-111

PL

W pracy omówiono sposoby korekcji kątowej głowicy fotometrycznej luksomierza. Poddano także analizie obecnie obowiązujące zalecenia dotyczące jakości tej korekcji. Analiza ta pozwala wyciągnąć wniosek, że przepisy normalizacyjne z tego zakresu, zarówno krajowe, jak i zagraniczne wymagają aktualizacji.

EN

In the paper of the errors of angular correction of a luxmeter photometric hea is discused

16

Badania długoczasowe detektorów UV

75%

Ćwirko J. , Ćwirko R.

Przegląd Elektrotechniczny

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2013

|

tom R. 89, nr 9

79-82

PL

Przy wyborze detektorów UV do konkretnej aplikacji należy uwzględnić, że ich parametry optyczne i elektryczne mogą się zmieniać w znacznym stopniu podczas eksploatacji, w wyniku zachodzenia w ich strukturze różnorodnych procesów degradacyjnych. Najczęstszymi źródłami tych procesów są długoczasowe poddawania struktury półprzewodnikowej detektora UV wpływowi silnego promieniowania termicznego lub/i optycznego.

EN

In the selection of the UV detector to a particular application should be considered that the optical and electrical parameters may vary considerably during operation due to the overlap in the composition of a variety of degradative processes. The most common sources of these processes are long-term semiconductor structures subjected UV detector strong influence of thermal radiation and / or optical.

17

Study of the Light Emitting Diode as a photoreceptor : spectral and electrical characterization as function of temperature and lighting source

75%

Vannacci E. , Granchi S. , Cecchi M. , Calzolai M. , Mazzi E. , Biagi E.

Opto-Electronics Review

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2018

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tom Vol. 26, No. 3

201--209

EN

In this study, the temperature influence on the spectral responsivity of a Light Emitting Diode (LED) used as a photoreceptor, combined to light source spectrum is correlated to electrical characteristics in order to propose an alternative method to estimate LED junction temperature, regardless of the absolute illumination intensity and based on the direct correlation between the integral of the product of two optical spectra and the photo-generated currents. A laboratory test bench for experimental optical measurements has been set in order to enable any characterizing of photoelectric devices in terms of spectral behaviour, in a wavelength range placed between 400–1000 nm, and of current-voltage characteristics as function of temperature by using two different illumination sources. The temperature is analysed in a range from 5°C up to 85°C, so as to evaluate thermal variation effects on the sensor performance. The photo-generated current of two LEDs with different peak wavelengths has been studied. Research has observed and mathematically analysed what follows: since the photo-generated current strictly depends on the combination between the spectral response of the photoreceptor and the lighting source response, it becomes possible to estimate indirectly the junction temperature of the LEDs by considering the ratio between the photogenerated currents obtained by using two different illumination sources. Such results may for one thing increase knowledge in the fields where LEDs are used as photo-detectors for many applications and for another, they could be extended to generic photodetectors, thus providing useful information in photovoltaic field, for instance.

18

Concepts of infrared and terahertz photodetectors based on vertical graphene van der Waals and HgTe-CdHgTe heterostructures

75%

Ryzhii M. , Otsuji T. , Ryzhii V. , Aleshkin V. , Dubinov A. , Karasik V. E. , Leiman V. , Mitin V. , Shur M. S.

Opto-Electronics Review

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2019

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tom Vol. 27, No. 2

219--223

EN

We review recently proposed concepts of infrared and terahertz photodetectors based on graphene van der Waals heterostructures and HgTe-CdHgTe quantum well heterostructures and demonstrate their potential.

19

Offset compensated baseline restoration and computationally efficient hybrid interpolation for the brain PET

75%

Qaisar S. M.

Bio-Algorithms and Med-Systems

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2018

|

tom Vol. 14, no. 4

art. no. 20180031

EN

The acquisition of positron emission tomography (PET) pulses introduces artifacts and limits the performance of the scanner. To minimize these inadequacies, this work focuses on the design of an offset compensated digital baseline restorer (BLR) along with a two-stage hybrid interpolator. They respectively treat the incoming pulse offsets and limited temporal resolution and improve the scanner performance in terms of calculating depth of interactions and line of responses. The offset of incoming PET pulses is compensated by the BLR and then their interesting parts are selected. The selected signal portion is up-sampled with a hybrid interpolator. It is composed of an optimized weighted least-squares interpolator (WLSI) and a simplified linear interpolator. The processes of calibrating the WLSI coefficients and characterizing the BLR and the interpolator modules are described. The functionality of the proposed modules is verified with an experimental setup. Results have shown that the devised BLR effectively compensates a dynamic range of bipolar offsets. The signal selection process allows focusing only on the relevant signal part and avoids the unnecessary operations during the post-interpolation process. Additionally, the hybrid nature allows improving the signal temporal resolution with an appropriate precession at a reduced computational complexity compared to the mono-interpolationbased arithmetically complex counterparts. The component-level architectures of the BLR and the interpolator modules are also described. It promises an efficient integration of these modules in modern PET scanners while using standard and economical analog-to-digital converters and field-programmable gate arrays. It avoids the development of high-performance and expensive application-specific integrated circuits and results in a costeffective realization.

20

Wide bandgap III-Nitride semiconductors : opportunities for future optoelectronics

63%

Park Y. S.

Opto-Electronics Review

|

2001

|

tom Vol. 9, No. 2

117-124

EN

The world at the end of the 20th century has become "blue". Indeed, this past decade has witnessed a "blue rush" towards the develpment of violet-blue-green light emitting diodes (LEDs) and laser diodes (LDs) based on wide bandgap III-Nitride semiconductors. And the hard work has culminated with, first, the demonstration of commercial high brightness blue and green LEDs and of commercial violet LDs, at the very and of this decade. Thanks to their extraordinary properties, these semiconductor materials have generated a plethora of activity in semiconductor science and technology. Novel approaches are explored daily to improve the current optoelectronics state-of-the-art. Such improvements will extend the usage and the efficiency of new light sources (e.g. white LEDs), support the rising information technology age (e.g. high density optical data storage), and enhance the environmental awareness capabilities of humans (ultraviolet and visible photon detectors and sensor). Such opportunities and many others will be reviewed in this presentation.