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1

Measurements of the responsivity of FET‐based detectors of sub‐THz radiation

Kopyt Paweł, Salski Bartłomiej, Pacewicz Adam, Zagrajek Przemysław, Marczewski Jacek

Opto-Electronics Review

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2019

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Vol. 27, No. 2

123--129

EN

This article describes a novel approach to measure responsivity of a FET-based sub-THz detector using on-wafer probes to directly feed a bare antenna-less detecting device. Thus, the approach eliminates the need to know beforehand the detector’s effective aperture, which can be a source of large variation between responsivity measurements of various FET-based detectors often cited in the literature. It seems that the presented method can be useful at making direct comparisons between responsivity of various devices (e.g., MOSFETs, HEMTs etc.). As a demonstration, the sub-THz responsivity of a pHEMT device fabricated using a commercial GaAs process has been measured in a WR-3 frequency band. Additionally, the results have been compared against data obtained using an alternative approach. The verification method consisted in integrating exactly the same device with a broad-band antenna and a carefully selected high-resistivity silicon lens and comparing its performance with that of a commercial calibrated detector based on Schottky diodes.

2

Numerical analysis of SiGeSn/GeSn interband quantum well infrared photodetector

Pareek P., Das M. K., Kumar S.

Opto-Electronics Review

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2018

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Vol. 26, No. 2

149--157

EN

In this paper, detailed theoretical investigation on the frequency response and responsivity of a strain bal-anced SiGeSn/GeSn quantum well infrared photodetector (QWIP) is made. Rate equation and continuity equation in the well are solved simultaneously to obtain photo generated current. Quantum mechanical carrier transport like carrier capture in QW, escape of carrier from the well due to thermionic emission and tunneling are considered in this calculation. Impact of Sn composition in the GeSn well on the frequency response, bandwidth and responsivity are studied. Results show that Sn concentration in the GeSn active layer and applied bias have important role on the performance of the device. Significant bandwidth is obtained at low reverse bias voltage, e.g., 200 GHz is obtained at 0.28 V bias for a single Ge0.83 Sn0.17 layer. Whereas, the maximum responsivity is of 8.6 mA/W at 0.5 V bias for the same structure. However, this can be enhanced by using MQW structure.

3

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

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2018

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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.

4

Influence of doping on the performance of GaAs/AlGaAs QWIP for long wavelength applications

Billaha A., Das M. K.

Opto-Electronics Review

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2016

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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.

5

Zastosowanie diod LED jako fotodetektorów w systemach transmisji VLC

Kowalczyk M.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2015

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nr 8-9

733--737

PL

Zapewnienie możliwości realizacji kanału zwrotnego w systemach VLC stanowi obecnie jeden z podstawowych problemów, który musi zostać rozwiązany, aby technologia ta mogła w przyszłości konkurować z systemami radiowej transmisji danych. Przedstawiono wyniki badań weryfikujących potencjalną możliwość wykorzystania diod świecących LED w roli fotodetektorów. Podejście to otwiera nowe możliwości w odniesieniu do tworzenia kanałów transmisji w systemach VLC. Przeprowadzone badania potwierdzają, że przynajmniej część diod świecących LED może pełnić taką rolę, jeżeli tylko zostaną odpowiednio spolaryzowane.

EN

Ensuring of feasibility the realization of feedback channel at the VLC systems, is currently, one of the key problems that must be solved, if we want believe in that this technology will got a real chance to compete with the data transmission radio systems in the future. Today, it's very difficult to predict, which of the proposed solutions in this regard eventually reaches a dominant position at the end. Perhaps, some of them will be operate in parallel. The paper presents the results of a verifying the potential possibility of using for this purpose the LEDs as photodetectors. This approach opens new possibilities in respect to create transmission channels at the VLC systems in very flexible way. The carried out studies confirm that at least some LEDs can act as photodetectors, if they are appropriately polarized only. The article is an extension of the work [1].

6

Wpływ kształtu modulowanego promieniowania optycznego na czułość napięciową detektora piroelektrycznego

Odon A.

Pomiary Automatyka Kontrola

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2012

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R. 58, nr 11

997-999

PL

Badania zależności czułości detektora piroelektrycznego od częstotliwości powinny być przeprowadzane przy zastosowaniu sinusoidalnie modulowanego promieniowania pobudzającego detektor. W praktyce eksperymentalnej często stosowane są elektromechaniczne modulatory, które zapewniają wytworzenie quasi-prostokątnego lub quasi-trapezowego kształtu przebiegu mocy promieniowania. Wyznaczona w ten sposób wartość czułości napięciowej detektora może być obarczona dużym błędem. W artykule przedstawiono rezultaty badań symulacyjnych, których celem jest wyznaczenie zależności czułości napięciowej od częstotliwości dla modelu detektora piroelektrycznego zaimplementowanego w programie MATLAB-Simulink i dokonanie oceny błędu pomiaru czułości spowodowanego zastosowaniem niesinusoidalnych przebiegów mocy promieniowania pobudzających detektor piroelektryczny.

EN

The voltage responsivity of a pyroelectric detector is one of the most important parameters characterizing its measuring properties. Sinusoidally modulated optical radiation should be used for experimental measuring of the pyroelectric detector responsivity. In practice rotating disk choppers are commonly used as a source of modulated optical signals in experimental setups. A disadvantage of using optical choppers is that the produced radiation may have a square or trapezoidal waveform. In the paper the results of simulation studies of the pyroelectric detector frequency response for sinusoidal, square and trapezoidal shape of the modulated radiation are presented. The simulation studies were carried out for the pyroelectric detektor model with use of program MATLAB-Simulink. Values of the main parameters of this detector were precisely specified. The frequency dependence of the pyroelectric detector voltage responsivity for different shapes of the absorbed radiation waveform is shown in Fig. 2. The simulation results show that the responsivity of the detector excited by a square wave of radiation has a much higher value (up to several hundred percent) in comparison to that obtained with sinusoidal modulation of radiation, especially at low frequencies. Trapezoidal modulation produces a much smaller error than the square wave modulation.

7

Fabrication and photoelectrical properties of a novel violet and blue enhanced SINP silicon photovoltaic device

Bo H., Ma Z. Q., Jing X., Lei Z., Sheng Z. N., Feng L., Feng L., Cheng S., Ling S., Jie M. X., Jie M. X., Yue Z. C., Shan Y. Z.., Ting Y. Y.

Optica Applicata

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2009

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Vol. 39, nr 3

547-560

EN

A novel ITO/SiO2/np-silicon violet and blue enhanced photovoltaic device with SINP structure has been fabricated by thermal diffusion of phosphorus. The shallow junction was formed to enhance the spectral responsivity within the wavelength range of 400-600 nm. An ultrathin silicon dioxide was thermally grown at low temperature and RF sputtering of ITO antireflection coating to reduce the reflected light and enhance the sensitivity. The crystalline structure, optical and electric properties of ITO film were determined by an XRD, UV-VIS spectrophotometer, a four point probe and the Hall effect measurement, respectively. The results show that ITO film has high quality. The current-voltage (I-V) characteristics, spectral response and responsivity of the photovoltaic device with high quantum efficiency of violet SINP and deep junction SINP structure were calculated and analyzed in detail.

8

Insight into performance of quantum dot infrared photodetectors

Martyniuk P., Rogalski A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2009

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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.

9

Electrical substitution cryogenic radiometer based spectral responsivity scale between 250–2500 nm wavelengths

Bazkir O., Samedov F.

Optica Applicata

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2004

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Vol. 34, nr 3

427-438

EN

This paper presents the spectral responsivity scale between 250–2500 nm developed by the National Metrology Institute of Turkey (UME). For that purpose silicon photodiode based trap detector and electrically calibrated pyroelectric radiometer (ECPR) that were calibrated against primary level absolute electrical substitution cryogenic radiometer (ESCR) were used as transfer standards. Using highly collimated and stabilized (10–5) lasers, absolute optical powers and absolute responsivity of trap detector were measured with an uncertainty of the order of 10–4. In visible (VIS) region responsivity scale was set by means of the models for the reflectance and internal quantum efficiency. In the ultraviolet (UV) and near-infrared (NIR) regions spectrally flat (0.1%) ECPR was used.

10

Quantum dot infrared photodetector

Liu H. C.

Opto-Electronics Review

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2003

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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.