Searched for: subject%3A%22Photoconductivity%22
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Zhang, H. (author)
In recent decades, dielectric lens antennas have been more and more adopted and developed for sensing and imaging applications at sub-millimeter (sub-mm) wavelengths because they can achieve high gain while keeping their physical size and weight acceptable at these wavelengths. More recently, as low-loss and low-cost lens materials have become...
doctoral thesis 2024
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Beijnen, Laurens (author)
Distributed feeding in photo-conducting antennas (PCAs) leads to simple optical designs, less prone to overheating, as well to terahertz (THz) antennas that can operate non-dispersively over wide bandwidths. However, the efficient analysis of pulsed PCAs was so far limited to architectures characterized by feeds small with respect to the THz...
master thesis 2023
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Neto, A. (author), Llombart, Nuria (author), Freni, Angelo (author)
In the circuit theory, the Norton and Thevenin equivalent generators are tools that simplify the solutions of networks involving passive or active components. They have been extensively used in the frequency domain to describe time-harmonic sources. A time-stepped evolution is instead typically used to include transient sources. As a...
journal article 2023
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Fiorellini Bernardis, A. (author), Sberna, P.M. (author), Bueno Lopez, J. (author), Zhang, H. (author), Llombart, Nuria (author), Neto, A. (author)
Drude's description of the response of low-temperature gallium arsenide to optical pulse excitation is used to evaluate the components of a time-domain Norton equivalent circuit of a photoconductive antenna (PCA) source. The saturation of the terahertz (THz) radiated power occurring at large optical excitation levels was previously associated...
journal article 2023
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Basyooni, Mohamed A. (author), Zaki, Shrouk E. (author), Rahmani, Khalid (author), En-nadir, Redouane (author), Eker, Yasin Ramazan (author)
Surface plasmon technology is regarded as having significant potential for the enhancement of the performance of 2D oxide semiconductors, especially in terms of improving the light absorption of 2D MoO3 photodetectors. An ultrathin MoO3/Ir/SiO2/Si heterojunction Schottky self-powered photodetector is introduced here to showcase positive...
journal article 2023
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Basyooni, Mohamed A. (author), Tihtih, Mohammed (author), Zaki, Shrouk E. (author), Eker, Yasin Ramazan (author)
Nanostructures of ultrathin 2D MoO<sub>3</sub> semiconductors have gained significant attention in the field of transparent optoelectronics and nanophotonics due to their exceptional responsiveness. In this study, we investigate self-powered α-MoO<sub>3</sub>/Ir/α-MoO<sub>3</sub> photodetectors, focusing on the influence of induced hot...
journal article 2023
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Dong, Yicong (author), Dowling, K.M. (author), Ghandiparsi, Soroush (author), Voss, Lars (author), Rakheja, Shaloo (author)
In this work, we demonstrate and model the deep-level defect physics of semi-insulating gallium arsenide bulk photoconductive semiconductor switches (PCSS) with gap size of 10 μ and 25 μ in dark-mode operation. Experimental measurements up to biasing field of 10 kV/cm show near-bistable characteristics in the dark-mode current-voltage...
journal article 2023
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Colombi, G. (author), Boshuizen, B. (author), Chaykina, D. (author), Hsu, Y. (author), Schreuders, H. (author), Savenije, T.J. (author), Dam, B. (author)
At ambient conditions, rare-earth oxyhydride thin films show reversible photochromism and photoconductivity, while their mechanism and relation are still unclear. In this work, this question is explored with in situ time-resolved measurements of both optical and transport properties of Gd-based oxyhydride thin films. It is found that p-type...
journal article 2023
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Huiskes, Martijn (author)
Photoconductive antennas (PCAs) are an interesting candidate for imaging systems due to their relatively low cost and ability to provide a bandwidth of hundreds of GHz. The large bandwidth of PCAs allows for sub-millimeter depth resolution. However, the often-used single-element PCAs are intrinsically limited in the amount of power they can...
master thesis 2022
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Fiorellini Bernardis, A. (author)
In recent years, the interest in terahertz technology witnessed a constant increasing interest and attention from the scientific community, as it allows to unlock the THz bandwidth, that can be used for a wide range of applications: it helps the study of biological samples and help medical diagnostics; it serves as a harmless non-destructive...
doctoral thesis 2022
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Nerkar, Saurabh (author)
THz time-domain systems driven by photoconductive antennas (PCAs) promise a bandwidth of the order of hundreds of GHz. This characteristic can be utilized to build see-through radars with sub-mm resolution and a field of view comparable to the current mm-wave radars at a relatively low cost. These radars can solve the issues in the field of...
master thesis 2021
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Fiorellini Bernardis, A. (author), Zhang, H. (author), Sberna, P.M. (author), Bueno Lopez, J. (author), Neto, A. (author), Llombart, Nuria (author)
The time evolution of voltages and currents in a pulsed photo conductive antenna (PCA) source is evaluated resorting to a rigorous procedure that stems from semiconductor physics first, to define the phenomena involved in the generation of the photocurrent, and then relies on an equivalent circuit in time domain, providing a direct estimation...
abstract 2021
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Pelekanidis, Antonios (author)
Photoconductive antennas have been used extensively for THz radiation the last few years. In this thesis, we propose a photoconductive connected dipole array consisting of 36x36 elements that is used as a feed in a THz silicon lens and radiates in a band ranging from 100 GHz to 5 THz. Specifically, we compute theoretically the radiated field...
master thesis 2020
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Gelvez Rueda, M.C. (author), Ahlawat, Paramvir (author), Merten, Lena (author), Jahanbakhshi, Farzaneh (author), Mladenović, Marko (author), Hinderhofer, Alexander (author), Dar, M. Ibrahim (author), Li, Yang (author), Grozema, F.C. (author)
Layered hybrid perovskites have emerged as a promising alternative to stabilizing hybrid organic–inorganic perovskite materials, which are predominantly based on Ruddlesden-Popper structures. Formamidinium (FA)-based Dion-Jacobson perovskite analogs are developed that feature bifunctional organic spacers separating the hybrid perovskite slabs...
journal article 2020
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Degasperi, Andrea (author)
Photoconductive antennas (PCAs) have been extensively utilized for the generation of broadband pulses over very large bandwidths. PCAs rely on a semiconductor (e.g. LT- GaAs) gap pumped by a laser and coupled to a passive structure biased at a certain voltage level. When the laser impinges on the semiconductor gap with an appropriate carrier...
master thesis 2019
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Garufo, A. (author), Sberna, P.M. (author), Carluccio, G. (author), Freeman, Joshua R. (author), Bacon, David R. (author), Li, Lianhe (author), Baselmans, J.J.A. (author), Llombart, Nuria (author), Neto, A. (author)
A pulsed photoconductive terahertz (THz) source is presented that is able to radiate milliwatt (mW) level average power over a large bandwidth, by exploiting both the optical and electrical properties of photoconductive sources and the ultrawideband properties of connected antenna arrays. An optical system composed of a microlenses array...
journal article 2019
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Garufo, A. (author), Carluccio, G. (author), Freeman, Joshua R. (author), Bacon, David R. (author), Llombart, Nuria (author), Linfield, Edmund H. (author), Davies, Alexander G. (author), Neto, A. (author)
This second part of two papers' sequence presents the experimental validation of the Norton equivalent circuit model for pulsed photoconductive antennas (PCAs) provided in the first paper of the sequence. To this goal, different prototypes of photoconductive antenna sources have been manufactured and assembled. The average powers radiated and...
journal article 2018
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Garufo, A. (author), Carluccio, G. (author), Llombart, Nuria (author), Neto, A. (author)
A novel equivalent circuit for pulsed photoconductive sources is introduced for describing the coupling between the photoconductive gap and the antenna. The proposed circuit effectively describes the mechanism of feeding the antenna by the semiconductor when this latter is illuminated by a laser operating in a pulsed mode. Starting from the...
journal article 2018
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Pilavaki, Evdokia (author), Valente, V. (author), Demosthenous, Andreas (author)
Point-of-care systems for the detection of infectious diseases are in great demand especially in developing countries. Lateral flow immunoassays are considered ideal biosensors for point-of-care diagnostics due to their numerous advantages. However, to quantify their results a low power, robust electronic reader is needed. A low power CMOS...
journal article 2018
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Weppelman, I.G.C. (author), Moerland, R.J. (author), Hoogenboom, J.P. (author), Kruit, P. (author)
We present a new method to create ultrashort electron pulses by integrating a photoconductive switch with an electrostatic deflector. This paper discusses the feasibility of such a system by analytical and numerical calculations. We argue that ultrafast electron pulses can be achieved for micrometer scale dimensions of the blanker, which are...
journal article 2018
Searched for: subject%3A%22Photoconductivity%22
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