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Author Kitaygorsky, J.; Komissarov, I.; Jukna, A.; Pan, D.; Minaeva, O.; Kaurova, N.; Divochiy, A.; Korneev, A.; Tarkhov, M.; Voronov, B.; Milostnaya, I.; Gol'tsman, G.; Sobolewski, R.R.
Title (up) Dark counts in nanostructured nbn superconducting single-photon detectors and bridges Type Journal Article
Year 2007 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 17 Issue 2 Pages 275-278
Keywords SSPD; SNSPD
Abstract We present our studies on dark counts, observed as transient voltage pulses, in current-biased NbN superconducting single-photon detectors (SSPDs), as well as in ultrathin (~4 nm), submicrometer-width (100 to 500 nm) NbN nanobridges. The duration of these spontaneous voltage pulses varied from 250 ps to 5 ns, depending on the device geometry, with the longest pulses observed in the large kinetic-inductance SSPD structures. Dark counts were measured while the devices were completely isolated (shielded by a metallic enclosure) from the outside world, in a temperature range between 1.5 and 6 K. Evidence shows that in our two-dimensional structures the dark counts are due to the depairing of vortex-antivortex pairs caused by the applied bias current. Our results shed some light on the vortex dynamics in 2D superconductors and, from the applied point of view, on intrinsic performance of nanostructured SSPDs.
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Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1248
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Author Verevkin, A.; Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.; Chulkova, G. M.; Smirnov, K. S.; Sobolewski, R.
Title (up) Direct measurements of energy relaxation times in two-dimensional structures under quasi-equilibrium conditions Type Conference Article
Year 2002 Publication Mater. Sci. Forum Abbreviated Journal Mater. Sci. Forum
Volume 384-3 Issue Pages 107-116
Keywords 2DEG, AlGaAs/GaAs
Abstract A new microwave technique was successfully applied for direct studies of energy relaxation times in two-dimensional AlGaAs/GaAs structures under quasi-equilibrium conditions in the nanosecond and picosecond time scale. We report our results of energy relaxation time measurements in the temperature range 1.6-50 K, in quantum Hall effect regime in magnetic fields up to 4 T.
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Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference Materials Science Forum
Notes Approved no
Call Number Serial 1536
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Author Jukna, A.; Kitaygorsky, J.; Pan, D.; Cross, A.; Perlman, A.; Komissarov, I.; Sobolewski, R.; Okunev, O.; Smirnov, K.; Korneev, A.; Chulkova, G.; Milostnaya, I.; Voronov, B.; Gol'tsman, G.
Title (up) Dynamics of hotspot formation in nanostructured superconducting stripes excited with single photons Type Journal Article
Year 2008 Publication Acta Physica Polonica A Abbreviated Journal Acta Physica Polonica A
Volume 113 Issue 3 Pages 955-958
Keywords SSPD, SNSPD
Abstract Dynamics of a resistive hotspot formation by near-infrared-wavelength single photons in nanowire-type superconducting NbN stripes was investigated. Numerical simulations of ultrafast thermalization of photon-excited nonequilibrium quasiparticles, their multiplication and out-diffusion from a site of the photon absorption demonstrate that 1.55 μm wavelength photons create in an ultrathin, two-dimensional superconducting film a resistive hotspot with the diameter which depends on the photon energy, and the nanowire temperature and biasing conditions. Our hotspot model indicates that under the subcritical current bias of the 2D stripe, the electric field penetrates the superconductor at the hotspot boundary, leading to suppression of the stripe superconducting properties and accelerated development of a voltage transient across the stripe.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1414
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Author Gol’tsman, G.; Okunev, O.; Chulkova, G.; Lipatov, A.; Dzardanov, A.; Smirnov, K.; Semenov, A.; Voronov, B.; Williams, C.; Sobolewski, R.
Title (up) Fabrication and properties of an ultrafast NbN hot-electron single-photon detector Type Journal Article
Year 2001 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 11 Issue 1 Pages 574-577
Keywords NbN SSPD, SNSPD
Abstract A new type of ultra-high-speed single-photon counter for visible and near-infrared wavebands based on an ultrathin NbN hot-electron photodetector (HEP) has been developed. The detector consists of a very narrow superconducting stripe, biased close to its critical current. An incoming photon absorbed by the stripe produces a resistive hotspot and causes an increase in the film’s supercurrent density above the critical value, leading to temporary formation of a resistive barrier across the device and an easily measurable voltage pulse. Our NbN HEP is an ultrafast (estimated response time is 30 ps; registered time, due to apparatus limitations, is 150 ps), frequency unselective device with very large intrinsic gain and negligible dark counts. We have observed sequences of output pulses, interpreted as single-photon events for very weak laser beams with wavelengths ranging from 0.5 /spl mu/m to 2.1 /spl mu/m and the signal-to-noise ratio of about 30 dB.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1558-2515 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1547
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Author Yang, J. K. W.; Dauler, E.; Ferri, A.; Pearlman, A.; Verevkin, A.; Gol’tsman, G.; Voronov, B.; Sobolewski, R.; Keicher, W. E.; Berggren, K. K.
Title (up) Fabrication development for nanowire GHz-counting-rate single-photon detectors Type Journal Article
Year 2005 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 15 Issue 2 Pages 626-630
Keywords NbN SSPD, SNSPD
Abstract We have developed a fabrication process for GHz-counting-rate, single-photon, high-detection-efficiency, NbN, nanowire detectors. We have demonstrated two processes for the device patterning, one based on the standard polymethylmethacrylate (PMMA) organic positive-tone electron-beam resist, and the other based on the newer hydrogen silsesquioxane (HSQ) negative-tone spin-on-glass resist. The HSQ-based process is simple and robust, providing high resolution and the prospect of high fill-factors. Initial testing results show superconductivity in the films, and suggest that the devices exhibit photosensitivity.
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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 1558-2515 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1466
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