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Author Semenov, A.; Richter, H.; Hübers, H.-W.; Petrenko, D.; Tretyakov, I.; Ryabchun, S.; Finkel, M.; Kaurova, N.; Gol’tsman, G.; Risacher, C.; Ricken, O.; Güsten, R.
Title Optimization of the intermediate frequency bandwidth in the THz HEB mixers Type Abstract
Year 2014 Publication Proc. 25th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 25th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 54
Keywords NbN HEB mixer
Abstract We report on the studies of the intermediate frequency (IF) bandwidth of quasi-optically coupled NbN hot-electron bolometer (HEB) mixers which are aimed at the optimization of the mixer performance at terahertz frequencies. Extension of the IF bandwidth due to the contribution of electron diffusion to the heat removal from NbN microbolometers has been already demonstrated for NbN HEBs at subterahertz frequencies. However, reducing the size of the microbolometer causes degradation of the noise temperature. Using in-situ multilayer manufacturing process we succeeded to improve the transparency of the contacts for electrons which go away from microbolometer to the metallic antenna. The improved transparency and hence coupling efficiency counterbalances the noise temperature degradation. HEB mixers were tested in a laboratory heterodyne receiver with a narrow-band cold filter which allowed us to eliminate direct detection. We used a local oscillator with a quantum cascade laser (QCL) at a frequency of 4.745 THz [1] which was developed for the H-Channel of the German Receiver for Astronomy at Terahertz frequencies (GREAT). Both the noise and gain bandwidth were measured in the IF range from 0.5 to 8 GHz using the hot-cold technique and preliminary calibrated IF analyzer with a tunable microwave filter. For optimized HEB geometry we found the noise bandwidth as large as 7 GHz. We compare our results with the conventional and the hot-spot mixer models and show that further extension of the IF bandwidth should be possible via improving the sharpness of the superconducting transition. The cross characterization of the HEB mixer was performed in the test bed of GREAT at the Max-Planck-Institut für Radioastronomie with the same QCL LO and delivered results which were consistent with the laboratory studies.
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ISSN ISBN Medium
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Notes Approved no
Call Number (up) Serial 1359
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Author Tretyakov, I.; Shurakov, A.; Perepelitsa, A.; Kaurova, N.; Svyatodukh, S.; Zilberley, T.; Ryabchun, S.; Smirnov, M.; Ovchinnikov, O.; Goltsman, G.
Title Room temperature silicon detector for IR range coated with Ag2S quantum dots Type Journal Article
Year 2019 Publication Phys. Status Solidi RRL Abbreviated Journal Phys. Status Solidi RRL
Volume 13 Issue 9 Pages 1900187-(1-6)
Keywords
Abstract For decades, silicon has been the chief technological semiconducting material of modern microelectronics and has a strong influence on all aspects of the society. Applications of Si-based optoelectronic devices are limited to the visible and near infrared (IR) ranges. For photons with an energy less than 1.12 eV, silicon is almost transparent. The expansion of the Si absorption to shorter wavelengths of the IR range is of considerable interest for optoelectronic applications. By creating impurity states in Si, it is possible to cause sub-bandgap photon absorption. Herein, an elegant and effective technology of extending the photo-response of Si toward the IR range is presented. This approach is based on the use of Ag 2 S quantum dots (QDs) planted on the surface of Si to create impurity states in the Si bandgap. The specific sensitivity of the room temperature zero-bias Si_Ag 2 Sp detector is 10 11 cm Hz W 1 at 1.55 μm. Given the variety of available QDs and the ease of extending the photo-response of Si toward the IR range, these findings open a path toward future studies and development of Si detectors for technological applications. The current research at the interface of physics and chemistry is also of fundamental importance to the development of Si optoelectronics.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1862-6254 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number (up) Serial 1149
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Author Shurakov, A.; Mikhailov, D.; Belikov, I.; Kaurova, N.; Zilberley, T.; Prikhodko, A.; Voronov, B.; Vasil’evskii, I.; Goltsman, G.
Title Planar Schottky diode with a Γ-shaped anode suspended bridge Type Conference Article
Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume 1695 Issue Pages 012154
Keywords Schottky diode, GaAs, InP substrate
Abstract In this paper we report on the fabrication of a planar Schottky diode utilizing a Г-shaped anode suspended bridge. The bridge maintains transition between the top and bottom level planes of a 1.4 µm thick GaAs mesa. To implement the profile of a suspended bridge and inward tilt of a mesa wall adjacent to it, we make use of an anisotropic etching of gallium arsenide. The geometry proposed enables the fabrication of a diode with mesa of an arbitrary thickness to mitigate AC losses in the diode layered structure at terahertz frequencies of interest. For frequencies beyond 1 THz, it is also beneficial to use the geometry for the implementation of n-GaAs/n-InGaAs heterojunction Schottky diodes grown on InP substrate.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1742-6588 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number (up) Serial 1152
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Author Shurakov, A.; Prikhodko, A.; Mikhailov, D.; Belikov, I.; Kaurova, N.; Voronov, B.; Goltsman, G.
Title Efficiency of a microwave reflectometry for readout of a THz multipixel Schottky diode direct detector Type Conference Article
Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume 1695 Issue Pages 012156
Keywords Shottky diode, THz, direct detector, multipixel camera
Abstract In this paper we report on the results of investigation of efficiency of a microwave reflectometry for readout of a terahertz multipixel Schottky diode direct detector. Decent capabilities of the microwave reflectometry readout were earlier justified by us for a hot electron bolometric direct detector. In case of a planar Schottky diode, we observed increase of an optical noise equivalent power by a factor of 2 compared to that measured within a conventional readout scheme. For implementation of a multipixel camera, a microwave reflectometer is to be used to readout each row of the camera, and the row switching is to be maintained by a CMOS analog multiplexer. The diodes within a row have to be equipped with filters to distribute the probing microwave signal properly. The simultaneous use of analog multiplexing and microwave reflectometry enables to reduce the camera response time by a factor of its number of columns.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1742-6588 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number (up) Serial 1153
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Author Tretyakov, I.; Shurakov, A.; Perepelitsa, A.; Kaurova, N.; Svyatodukh, S.; Zilberley, T.; Ryabchun, S.; Smirnov, M.; Ovchinnikov, O.; Goltsman, G.
Title Silicon room temperature IR detectors coated with Ag2S quantum dots Type Conference Article
Year 2019 Publication Proc. IWQO Abbreviated Journal Proc. IWQO
Volume Issue Pages 369-371
Keywords silicon detector, quantum dot, IR, surface states
Abstract For decades silicon has been the chief technological semiconducting material of modern microelectronics. Application of silicon detectors in optoelectronic devices are limited to the visible and near infrared ranges, due to their transparency for radiation with a wavelength higher than 1.1 μm. The expansion Si absorption towards longer wave lengths is a considerable interest to optoelectronic applications. In this work we present an elegant and effective solution to this problem using Ag2S quantum dots, creating impurity states in Si to cause sub-band gap photon absorption. The sensitivity of room temperature zero-bias Si_Ag2S detectors, which we obtained is 1011 cmHzW . Given the variety of QDs parameters such as: material, dimensions, our results open a path towards the future study and development of Si detectors for technological applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 978-5-89513-451-1 Medium
Area Expedition Conference
Notes Approved no
Call Number (up) Serial 1154
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