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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. url  doi
openurl 
  Title Electron energy relaxation in disordered superconducting NbN films Type Journal Article
  Year 2020 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B  
  Volume (up) 102 Issue 5 Pages 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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  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 Baeva, E. M.; Titova, N. A.; Kardakova, A. I.; Piatrusha, S. U.; Khrapai, V. S. url  doi
openurl 
  Title Universal bottleneck for thermal relaxation in disordered metallic films Type Journal Article
  Year 2020 Publication JETP Lett. Abbreviated Journal Jetp Lett.  
  Volume (up) 111 Issue 2 Pages 104-108  
  Keywords NbN disordered metallic films, thermal relaxation  
  Abstract We study the heat relaxation in current biased metallic films in the regime of strong electron–phonon coupling. A thermal gradient in the direction normal to the film is predicted, with a spatial temperature profile determined by the temperature-dependent heat conduction. In the case of strong phonon scattering, the heat conduction occurs predominantly via the electronic system and the profile is parabolic. This regime leads to the linear dependence of the noise temperature as a function of bias voltage, in spite of the fact that all the dimensions of the film are large compared to the electron–phonon relaxation length. This is in stark contrast to the conventional scenario of relaxation limited by the electron–phonon scattering rate. A preliminary experimental study of a 200-nm-thick NbN film indicates the relevance of our model for materials used in superconducting nanowire single-photon detectors.  
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  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-3640 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1164  
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Author Rasulova, G. K.; Pentin, I. V.; Vakhtomin, Y. B.; Smirnov, K. V.; Khabibullin, R. A.; Klimov, E. A.; Klochkov, A. N.; Goltsman, G. N. url  doi
openurl 
  Title Pulsed terahertz radiation from a double-barrier resonant tunneling diode biased into self-oscillation regime Type Journal Article
  Year 2020 Publication J. Appl. Phys. Abbreviated Journal J. Appl. Phys.  
  Volume (up) 128 Issue 22 Pages 224303 (1 to 11)  
  Keywords HEB, resonant tunneling diode, RTD  
  Abstract The study of the bolometer response to terahertz (THz) radiation from a double-barrier resonant tunneling diode (RTD) biased into the negative differential conductivity region of the I–V characteristic revealed that the RTD emits two pulses in a period of intrinsic self-oscillations of current. The bolometer pulse repetition rate is a multiple of the fundamental frequency of the intrinsic self-oscillations of current. The bolometer pulses are detected at two critical points with a distance between them being half or one-third of a period of the current self-oscillations. An analysis of the current self-oscillations and the bolometer response has shown that the THz photon emission is excited when the tunneling electrons are trapped in (the first pulse) and then released from (the second pulse) miniband states.  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1262  
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Author Ovchinnikov, O. V.; Perepelitsa, A. S.; Smirnov, M. S.; Latyshev, A. N.; Grevtseva, I. G.; Vasiliev, R. B.; Goltsman, G. N.; Vitukhnovsky, A. G. url  doi
openurl 
  Title Luminescence of colloidal Ag2S/ZnS core/shell quantum dots capped with thioglycolic acid Type Journal Article
  Year 2020 Publication J. Luminescence Abbreviated Journal J. Luminescence  
  Volume (up) 220 Issue Pages 117008 (1 to 7)  
  Keywords Ag2S QD, quantum dots  
  Abstract The features of IR luminescence of colloidal AgS QDs passivated with thioglycolic acid (AgS/TGA) under the formation of AgS/ZnS/TGA core/shell QDs are considered. A 4.5-fold increase in the quantum yield of recombination IR luminescence within the band with a peak at 960 nm (1.29 eV), full width at half maximum of 250 nm (0.34 eV), and the Stokes shift with respect to the exciton absorption of 0.6 eV was found. The increase in the IR luminescence intensity of AgS/ZnS/TGA QDs is accompanied by an increase in the average luminescence lifetime from 2.9 ns to 14.3 ns, which is explained as “healing” of surface trap states during the formation of the ZnS shell. For the first time, the enhancement of the luminescence intensity photodegradation (hereinafter referred to as fatigue) was found during the formation of the AgS/ZnS/TGA core/shell QDs. The luminescence fatigue is irreversible. We conclude that the initial stage of photolysis of the AgS core QDs under laser irradiation plays a key role. Low-atomic photolytic clusters of silver formed on the AgS core QDs act as luminescence quenching centers and do not reveal structural transformations into AgS, provided that the clusters are not in contact with TGA.  
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  Corporate Author Thesis  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-2313 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1267  
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Author Vasilev, D. D.; Malevannaya, E. I.; Moiseev, K. M.; Zolotov, P. I.; Antipov, A. V.; Vakhtomin, Y. B.; Smirnov, K. V. url  doi
openurl 
  Title Influence of deposited material energy on superconducting properties of the WSi films Type Conference Article
  Year 2020 Publication IOP Conf. Ser.: Mater. Sci. Eng. Abbreviated Journal IOP Conf. Ser.: Mater. Sci. Eng.  
  Volume (up) 781 Issue Pages 012013 (1 to 6)  
  Keywords WSi SSPD, SNSPD  
  Abstract WSi thin films have the advantages for creating SNSPDs with a large active area or array of detectors on a single substrate due to the amorphous structure. The superconducting properties of ultrathin WSi films substantially depends on their structure and thickness as the NbN films. Scientific groups investigating WSi films mainly focused only on changes of their thickness and the ratio of the components on the substrate at room temperature. This paper presents experiments to determine the effect of the bias potential on the substrate, the temperature of the substrate, and the peak power of pulsed magnetron sputtering, which is the equivalent of ionization, a tungsten target, on the surface resistance and superconducting properties of the WSi ultrathin films. The negative effect of the substrate temperature and the positive effect of the bias potential and the ionization coefficient (peak current) allow one to choose the best WSi films formation mode for SNSPD: substrate temperature 297 K, bias potential -60 V, and peak current 3.5 A.  
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  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1757-899X ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1798  
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Author Antipov, A. V.; Seleznev, V. A.; Vakhtomin, Y. B.; Morozov, P. V.; Vasilev, D. D.; Malevannaya, E. I.; Moiseev, K. M.; Smirnov, K. url  doi
openurl 
  Title Investigation of WSi and NbN superconducting single-photon detectors in mid-IR range Type Conference Article
  Year 2020 Publication IOP Conf. Ser.: Mater. Sci. Eng. Abbreviated Journal IOP Conf. Ser.: Mater. Sci. Eng.  
  Volume (up) 781 Issue Pages 012011 (1 to 5)  
  Keywords WSi, NbN SSPD, SNSPD  
  Abstract Spectral characteristics of WSi and NbN superconducting single-photon detectors with different surface resistance and width of nanowire strips have been investigated in the wavelength range of 1.3-2.5 μm. WSi structures with narrower strips demonstrated better performance for detection of single photons in longer wavelength range. The difference in normalized photon count rate for such structures reaches one order of magnitude higher in comparison with structures based on NbN thin films at 2.5 μm.  
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  Corporate Author Thesis  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1757-899X ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1799  
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Author Elmanova, A.; An, P.; Kovalyuk, V.; Golikov, A.; Elmanov, I.; Goltsman, G. url  doi
openurl 
  Title Study of silicon nitride O-ring resonator for gas-sensing applications Type Conference Article
  Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.  
  Volume (up) 1695 Issue Pages 012124  
  Keywords silicon nitride O-ring resonator, ORR  
  Abstract In this work, we experimentally studied the influence of different gaseous surroundings on silicon nitride O-ring resonator transmission. We compared the obtained results with numerical calculations and theoretical analysis and found a good agreement between them. Our results have a great potential for gas sensing applications, where a compact footprint and high efficiency are desired simultaneously.  
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  Corporate Author Thesis  
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  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 Serial 1176  
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Author Shurakov, A.; Mikhailov, D.; Belikov, I.; Kaurova, N.; Zilberley, T.; Prikhodko, A.; Voronov, B.; Vasil’evskii, I.; Goltsman, G. url  doi
openurl 
  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 (up) 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  
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  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 Serial 1152  
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Author Shurakov, A.; Prikhodko, A.; Mikhailov, D.; Belikov, I.; Kaurova, N.; Voronov, B.; Goltsman, G. url  doi
openurl 
  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 (up) 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 Serial 1153  
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Author Titova, N. A.; Baeva, E. M.; Kardakova, A. I.; Goltsman, G. N. url  doi
openurl 
  Title Fabrication of NbN/SiNx:H/SiO2 membrane structures for study of heat conduction at low temperatures Type Conference Article
  Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.  
  Volume (up) 1695 Issue Pages 012190  
  Keywords NbN films, insulating membrane  
  Abstract Here we report on the development of NbN/SiNx:H/SiO2-membrane structures for investigation of the thermal transport at low temperatures. Thin NbN films are known to be in the regime of a strong electron-phonon coupling, and one can assume that the phononic and electronic baths in the NbN are in local equilibrium. In such case, the cooling of the NbN-based devices strongly depends on acoustic matching to the substrate and substrate thermal characteristics. For the insulating membrane much thicker than the NbN film, our preliminary results demonstrate that the membrane serves as an additional channel for the thermal relaxation of the NbN sample. That implies a negligible role of thermal boundary resistance of the NbN-SiNx:H interface in comparison with the internal thermal resistance of the insulating membrane.  
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  Corporate Author Thesis  
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  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 Serial 1165  
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Author Komrakova, S.; Kovalyuk, V.; An, P.; Golikov, A.; Rybin, M.; Obraztsova, E.; Goltsman, G. url  doi
openurl 
  Title Effective absorption coefficient of a graphene atop of silicon nitride nanophotonic circuit Type Conference Article
  Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.  
  Volume (up) 1695 Issue Pages 012135  
  Keywords silicon nitride O-ring resonator, ORR  
  Abstract In this paper, we demonstrate the results of a study of the optical absorption properties of graphene integrated with silicon nitride O-ring resonator. We fabricated an array of O-ring resonators with different graphene coverage area atop. By measuring the transmission spectra of nanophotonic devices with and without graphene, we calculated the effective absorption coefficient of the graphene on a rib silicon nitride waveguide.  
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  Corporate Author Thesis  
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  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 Serial 1177  
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Author Prokhodtsov, A.; Kovalyuk, V.; An, P.; Golikov, A.; Shakhovoy, R.; Sharoglazova, V.; Udaltsov, A.; Kurochkin, Y.; Goltsman, G. url  doi
openurl 
  Title Silicon nitride Mach-Zehnder interferometer for on-chip quantum random number generation Type Conference Article
  Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.  
  Volume (up) 1695 Issue Pages 012118  
  Keywords Mach-Zehnder interferometer, MZI  
  Abstract In this work, we experimentally studied silicon nitride Mach-Zehnder interferometer (MZI) with two directional couplers and 400 ps optical delay line for telecom wavelength 1550 nm. We achieved the extinction ratio in a range of 0.76-13.86 dB and system coupling losses of 28-44 dB, depending on the parameters of directional couplers. The developed interferometer is promising for the use in a compact random number generator for the needs of a fully integrated quantum cryptography system, where compact design, as well as high generation speed, are needed.  
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  Corporate Author Thesis  
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  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 Serial 1178  
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Author Venediktov, I. O.; Elezov, M. S.; Prokhodtsov, A. I.; Kovalyuk, V. V.; An, P. P.; Golikov, A. D.; Shcherbatenko, M. L.; Sych, D. V.; Goltsman, G. N. url  doi
openurl 
  Title Study of microheater’s phase modulation for on-chip Kennedy receiver Type Conference Article
  Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.  
  Volume (up) 1695 Issue Pages 012117  
  Keywords Mach-Zehnder interferometers, MZI  
  Abstract In this work we describe phase modulators for several Mach-Zehnder interferometers (MZI) on silicon nitride platform for telecomm wavelength (1550 nm). We obtained current-voltage and phase-voltage curves for these modulators. MZI are needed for experimental realisation of various quantum receivers that can distinguish weak coherent states of light with extremely low error. Thermo-optical (TO) modulation is ensured by microheaters on one of the arms of MZI, which enables the change of the refractive index of the material with temperature. This approach allows to apply the necessary voltage to the golden microheaters to obtain the required phase change. For the on-chip microheaters we demonstrate the dependence of the phase shift on the voltage applied to our on-chip microheaters.  
  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 1742-6588 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1179  
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Author Elmanov, I.; Sardi, F.; Xia, K.; Kornher, T.; Kovalyuk, V.; Prokhodtsov, A.; An, P.; Kuzin, A.; Elmanova, A.; Goltsman, G.; Kolesov, R. url  doi
openurl 
  Title Development of focusing grating couplers for lithium niobate on insulator platform Type Conference Article
  Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.  
  Volume (up) 1695 Issue Pages 012127  
  Keywords grating couplers, lithium niobat  
  Abstract In this paper, we fabricate and experimentally study focusing grating couplers for lithium niobate on an insulator photonic platform. The transmittance of a waveguide equipped with in- and out-couplers with respect to the grating period is measured with and without silicon dioxide cladding applied. Our results show the influence of silicon dioxide cladding on the efficiency and the central wavelength of grating couplers and can be used to improve grating coupling efficiency. Our study is supported by numerical simulations.  
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  Corporate Author Thesis  
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  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 Serial 1180  
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Author Simonov, N. O.; Korneeva, Y. P.; Korneev, A. A.; Goltsman, G. N. url  doi
openurl 
  Title Enhance of the superconducting properties of the NbN/Au bilayer bridges Type Conference Article
  Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.  
  Volume (up) 1695 Issue Pages 012132 (1 to 4)  
  Keywords SSPD, SNSPD  
  Abstract We experimentally demonstrate strong temperature dependence of the critical current of the superconducting 600-nm-wide and 5-μm-long bridge made of NbN/Au bilayer. The result is achieved due to the proximity effect realized between the highly disordered superconducting NbN layer and low resistive normal-metal Au layer.  
  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 1742-6588 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1263  
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