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Author Sidorova, M.; Semenov, Alexej D.; Hübers, H.-W.; Ilin, K.; Siegel, M.; Charaev, I.; Moshkova, M.; Kaurova, N.; Goltsman, G. N.; Zhang, X.; Schilling, A.
Title Electron energy relaxation in disordered superconducting NbN films Type Journal Article
Year 2020 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 102 Issue 5 Pages (up) 054501 (1 to 15)
Keywords NbN SSPD, SNSPD, HEB, bandwidth, relaxation time
Abstract We report on the inelastic-scattering rate of electrons on phonons and relaxation of electron energy studied by means of magnetoconductance, and photoresponse, respectively, in a series of strongly disordered superconducting NbN films. The studied films with thicknesses in the range from 3 to 33 nm are characterized by different Ioffe-Regel parameters but an almost constant product qTl (qT is the wave vector of thermal phonons and l is the elastic mean free path of electrons). In the temperature range 14–30 K, the electron-phonon scattering rates obey temperature dependencies close to the power law 1/τe−ph∼Tn with the exponents n≈3.2–3.8. We found that in this temperature range τe−ph and n of studied films vary weakly with the thickness and square resistance. At 10 K electron-phonon scattering times are in the range 11.9–17.5 ps. The data extracted from magnetoconductance measurements were used to describe the experimental photoresponse with the two-temperature model. For thick films, the photoresponse is reasonably well described without fitting parameters, however, for thinner films, the fit requires a smaller heat capacity of phonons. We attribute this finding to the reduced density of phonon states in thin films at low temperatures. We also show that the estimated Debye temperature in the studied NbN films is noticeably smaller than in bulk material.
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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 2469-9950 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1266
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Author Korneev, A.; Minaeva, O.; Divochiy, A.; Antipov, A.; Kaurova, N.; Seleznev, V.; Voronov, B.; Gol’tsman, G.; Pan, D.; Kitaygorsky, J.; Slysz, W.; Sobolewski, R.
Title Ultrafast and high quantum efficiency large-area superconducting single-photon detectors Type Conference Article
Year 2007 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 6583 Issue Pages (up) 65830I (1 to 9)
Keywords SSPD, SNSPD, superconducting NbN films, infrared single-photon detectors
Abstract We present our latest generation of superconducting single-photon detectors (SSPDs) patterned from 4-nm-thick NbN films, as meander-shaped  0.5-mm-long and  100-nm-wide stripes. The SSPDs exhibit excellent performance parameters in the visible-to-near-infrared radiation wavelengths: quantum efficiency (QE) of our best devices approaches a saturation level of  30% even at 4.2 K (limited by the NbN film optical absorption) and dark counts as low as 2x10-4 Hz. The presented SSPDs were designed to maintain the QE of large-active-area devices, but, unless our earlier SSPDs, hampered by a significant kinetic inductance and a nanosecond response time, they are characterized by a low inductance and GHz counting rates. We have designed, simulated, and tested the structures consisting of several, connected in parallel, meander sections, each having a resistor connected in series. Such new, multi-element geometry led to a significant decrease of the device kinetic inductance without the decrease of its active area and QE. The presented improvement in the SSPD performance makes our detectors most attractive for high-speed quantum communications and quantum cryptography applications.
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Corporate Author Thesis
Publisher Spie Place of Publication Editor Dusek, M.; Hillery, M.S.; Schleich, W.P.; Prochazka, I.; Migdall, A.L.; Pauchard, A.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1249
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Author Slysz, W.; Wegrzecki, M.; Bar, J.; Grabiec, P.; Gorska, M.; Rieger, E.; Dorenbos, P.; Zwiller, V.; Milostnaya, I.; Minaeva, O.; Antipov, A.; Okunev, O.; Korneev, A.; Smirnov, K.; Voronov, B.; Kaurova, N.; Gol’tsman, G.N.; Kitaygorsky, J.; Pan, D.; Pearlman, A.; Cross, A.; Komissarov, I.; Sobolewski, R.
Title Fiber-coupled NbN superconducting single-photon detectors for quantum correlation measurements Type Conference Article
Year 2007 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 6583 Issue Pages (up) 65830J (1 to 11)
Keywords NbN SSPD, SNSPD, superconducting single-photon detectors, single-photon detectors, fiber-coupled optical detectors, quantum correlations, superconducting devices
Abstract We have fabricated fiber-coupled superconducting single-photon detectors (SSPDs), designed for quantum-correlationtype experiments. The SSPDs are nanostructured ( 100-nm wide and 4-nm thick) NbN superconducting meandering stripes, operated in the 2 to 4.2 K temperature range, and known for ultrafast and efficient detection of visible to nearinfrared photons with almost negligible dark counts. Our latest devices are pigtailed structures with coupling between the SSPD structure and a single-mode optical fiber achieved using a micromechanical photoresist ring placed directly over the meander. The above arrangement withstands repetitive thermal cycling between liquid helium and room temperature, and we can reach the coupling efficiency of up to  33%. The system quantum efficiency, measured as the ratio of the photons counted by SSPD to the total number of photons coupled into the fiber, in our early devices was found to be around 0.3 % and 1% for 1.55 &mgr;m and 0.9 &mgr;m photon wavelengths, respectively. The photon counting rate exceeded 250 MHz. The receiver with two SSPDs, each individually biased, was placed inside a transport, 60-liter liquid helium Dewar, assuring uninterrupted operation for over 2 months. Since the receiver’s optical and electrical connections are at room temperature, the set-up is suitable for any applications, where single-photon counting capability and fast count rates are desired. In our case, it was implemented for photon correlation experiments. The receiver response time, measured as a second-order photon cross-correlation function, was found to be below 400 ps, with timing jitter of less than 40 ps.
Address
Corporate Author Thesis
Publisher Spie Place of Publication Editor Dusek, M.; Hillery, M.S.; Schleich, W.P.; Prochazka, I.; Migdall, A.L.; Pauchard, A.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference Photon Counting Applications, Quantum Optics, and Quantum Cryptography
Notes Approved no
Call Number Serial 1431
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Author Antipov, S.; Trifonov, A.; Krause, S.; Meledin, D.; Kaurova, N.; Rudzinski, M.; Desmaris, V.; Belitsky, V.; Goltsman, G.
Title Improved bandwidth of a 2 THz hot-electron bolometer heterodyne mixer fabricated on sapphire with a GaN buffer layer Type Journal Article
Year 2019 Publication Supercond. Sci. Technol. Abbreviated Journal Supercond. Sci. Technol.
Volume 32 Issue 7 Pages (up) 075003
Keywords NbN HEB mixer, GaN buffer layer, sapphire substrate
Abstract We report on the signal-to-noise and gain bandwidth of a niobium nitride (NbN) hot-electron bolometer (HEB) mixer at 2 THz fabricated on a sapphire substrate with a GaN buffer layer. Two mixers with different DC properties and geometrical dimensions were studied and they demonstrated very close bandwidth performance. The signal-to-noise bandwidth is increased to 8 GHz in comparison to the previous results, obtained without a buffer-layer. The data were taken in a quasi-optical system with the use of the signal-to-noise method, which is close to the signal levels used in actual astrophysical observations. We find an increase of the gain bandwidth to 5 GHz. The results indicate that prior results obtained on a substrate of crystalline GaN can also be obtained on a conventional sapphire substrate with a few micron MOCVD-deposited GaN buffer-layer.
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Corporate Author Thesis
Publisher IOP Publishing Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Antipov_2019 Serial 1277
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Author Shcherbatenko, M.; Tretyakov, I.; Lobanov, Yu.; Maslennikov, S. N.; Kaurova, N.; Finkel, M.; Voronov, B.; Goltsman, G.; Klapwijk, T. M.
Title Nonequilibrium interpretation of DC properties of NbN superconducting hot electron bolometers Type Journal Article
Year 2016 Publication Appl. Phys. Lett. Abbreviated Journal
Volume 109 Issue 13 Pages (up) 132602
Keywords HEB mixer, contacts
Abstract We present a physically consistent interpretation of the dc electrical properties of niobiumnitride (NbN)-based superconducting hot-electron bolometer mixers, using concepts of nonequilibrium superconductivity. Through this, we clarify what physical information can be extracted from the resistive transition and the dc current-voltage characteristics, measured at suitably chosen temperatures, and relevant for device characterization and optimization. We point out that the intrinsic spatial variation of the electronic properties of disordered superconductors, such as NbN, leads to a variation from device to device.
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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 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1107
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