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Author Baselmans, J. J. A.; Baryshev, A.; Reker, S. F.; Hajenius, M.; Gao, J. R.; Klapwijk, T. M.; Voronov, B.; Gol’tsman, G.
Title Influence of the direct response on the heterodyne sensitivity of hot electron bolometer mixers Type Journal Article
Year 2006 Publication J. Appl. Phys. Abbreviated Journal J. Appl. Phys.
Volume 100 Issue (down) 8 Pages 084510 (1 to 7)
Keywords NbN HEB mixers
Abstract We present a detailed experimental study of the direct detection effect in a small volume (0.15μm×1μm×3.5nm) quasioptical NbN phonon cooled hot electron bolometer mixer at 673GHz. We find that the small signal noise temperature, relevant for an astronomical observation, is 20% lower than the noise temperature obtained using 300 and 77K calibration loads. In a separate set of experiments we show that the direct detection effect is caused by a combination of bias current reduction when switching from the 77 to the 300K

load in combination with the bias current dependence of the receiver gain. The bias current dependence of the receiver gain is shown to be mainly caused by the current dependence of the mixer gain.
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Language Summary Language Original Title
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ISSN 0021-8979 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1442
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Author Hajenius, M.; Baselmans, J. J. A.; Baryshev, A.; Gao, J. R.; Klapwijk, T. M.; Kooi, J. W.; Jellema, W.; Yang, Z. Q.
Title Full characterization and analysis of a terahertz heterodyne receiver based on a NbN hot electron bolometer Type Journal Article
Year 2006 Publication J. Appl. Phys. Abbreviated Journal
Volume 100 Issue (down) 7 Pages 074507
Keywords HEB
Abstract
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Publisher Place of Publication Editor
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 RPLAB @ s @ Serial 385
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Author Romijn, J.; Klapwijk, T. M.; Renne, M. J.; Mooij, J. E.
Title Critical pair-breaking current in superconducting aluminum strips far below Tc Type Journal Article
Year 1982 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 26 Issue (down) 7 Pages 3648-3655
Keywords superconducting nanowire
Abstract Critical currents of narrow, thin aluminum strips have been measured as a function of temperature. For the smallest samples uniformity of the current density is obtained over a large temperature range. Hence the intrinsic limit on the currentcarrying capacity of the superconductor was measured outside the Ginzburg-Landau -regime. The experimental values are compared with recent theoretical predictions by Kupriyanov and Lukichev. An approximate method of solving their equations is given, the results of which agree with the exact solution to within 1%. Experimental data are in excellent agreement with theoretical predictions. The absolute values agree if one assumes a ρl value of 4×10–16 Ωm2 with vF=1.3×106 m/s. This value for ρl is the same as that found from measurements of the anomalous skin effect but differs from values extracted from size-effect-limited resistivity.
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Notes Recommended by Klapwijk Approved no
Call Number Serial 925
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Author Klapwijk, T. M.; Semenov, A. V.
Title Engineering physics of superconducting hot-electron bolometer mixers Type Journal Article
Year 2017 Publication IEEE Trans. THz Sci. Technol. Abbreviated Journal IEEE Trans. THz Sci. Technol.
Volume 7 Issue (down) 6 Pages 627-648
Keywords HEB mixers
Abstract Superconducting hot-electron bolometers are presently the best performing mixing devices for the frequency range beyond 1.2 THz, where good-quality superconductor-insulator-superconductor devices do not exist. Their physical appearance is very simple: an antenna consisting of a normal metal, sometimes a normal-metal-superconductor bilayer, connected to a thin film of a narrow short superconductor with a high resistivity in the normal state. The device is brought into an optimal operating regime by applying a dc current and a certain amount of local-oscillator power. Despite this technological simplicity, its operation has found to be controlled by many different aspects of superconductivity, all occurring simultaneously. A core ingredient is the understanding that there are two sources of resistance in a superconductor: a charge-conversion resistance occurring at a normal-metal-superconductor interface and a resistance due to time-dependent changes of the superconducting phase. The latter is responsible for the actual mixing process in a nonuniform superconducting environment set up by the bias conditions and the geometry. The present understanding indicates that further improvement needs to be found in the use of other materials with a faster energy relaxation rate. Meanwhile, several empirical parameters have become physically meaningful indicators of the devices, which will facilitate the technological developments.
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ISSN 2156-342X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1292
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Author Kardakova, A.; Shishkin, A.; Semenov, A.; Goltsman, G. N.; Ryabchun, S.; Klapwijk, T. M.; Bousquet, J.; Eon, D.; Sacépé, B.; Klein, T.; Bustarret, E.
Title Relaxation of the resistive superconducting state in boron-doped diamond films Type Journal Article
Year 2016 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 93 Issue (down) 6 Pages 064506
Keywords boron-doped diamond films, resistive superconducting state, relaxation time
Abstract We report a study of the relaxation time of the restoration of the resistive superconducting state in single crystalline boron-doped diamond using amplitude-modulated absorption of (sub-)THz radiation (AMAR). The films grown on an insulating diamond substrate have a low carrier density of about 2.5×1021cm−3 and a critical temperature of about 2K. By changing the modulation frequency we find a high-frequency rolloff which we associate with the characteristic time of energy relaxation between the electron and the phonon systems or the relaxation time for nonequilibrium superconductivity. Our main result is that the electron-phonon scattering time varies clearly as T−2, over the accessible temperature range of 1.7 to 2.2 K. In addition, we find, upon approaching the critical temperature Tc, evidence for an increasing relaxation time on both sides of Tc.
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ISSN 2469-9950 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1167
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