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Author Heslinga, D. R.; Shafranjuk, S. E.; van Kempen, H.; Klapwijk, T. M.
Title (up) Observation of double-gap-edge Andreev reflection at Si/Nb interfaces by point-contact spectroscopy Type Journal Article
Year 1994 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 49 Issue 15 Pages 10484-10494
Keywords Nb, Si, Nb-Si, Nb/Si, Si/Nb, Andreev reflection, point-contact spectroscopy
Abstract Andreev reflection point-contact spectroscopy is performed on a bilayer consisting of 50-nm degenerately doped Si backed with Nb. Due to the short mean free path both injection into and transport across the Si layer are diffusive, in contrast to the ballistic conditions prevailing in clean metal layers. Nevertheless a large Andreev signal is observed in the point-contact characteristics, not reduced by elastic scattering in the Si layer or by interface scattering, but only limited by the transmission coefficient of the metal-semiconductor point contact. Two peaks in the Andreev reflection probability are visible, marking the values of the superconducting energy gap at the interface on the Nb and Si sides. This interpretation is supported by a method of solving the Bogolubov equations analytically using a simplified expression for the variation of the order parameter close to the interface. This observation enables a comparison with theoretical predictions of the gap discontinuity in the proximity effect. It is found that the widely used de Gennes model does not agree with the experimental data.
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Publisher American Physical Society Place of Publication Editor
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Notes Approved no
Call Number Serial 1005
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Author Lindgren, M.; Zorin, M. A.; Trifonov, V.; Danerud, M.; Winkler, D.; Karasik, B. S.; Gol'tsman, G. N.; Gershenzon, E. M.
Title (up) Optical mixing in a patterned YBa2Cu3O7-δ thin film Type Journal Article
Year 1994 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.
Volume 65 Issue 26 Pages 3398-3400
Keywords YBCO HTS HEB mixer, bandwidth
Abstract Mixing of 1.56 µm infrared radiation from two lasers in a high quality YBa2Cu3O7-δ thin film, patterned to parallel strips, was demonstrated. A mixer bandwidth of 18 GHz, limited by the measurement system, was obtained. A model based on nonequilibrium electron heating gives a good fit to the data and predicts an intrinsic mixer bandwidth in excess of 100 GHz, operating in the whole infrared spectrum. Reduction of bolometric effects and ways to decrease the conversion loss of the mixer is discussed. The minimum conversion loss is expected to be ~10 dB.
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ISSN 0003-6951 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 251
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Author Hong, Kyushik; Marsh, P. F.; Geok-Ing Ng; Pavlidis, D.; Hong, Chang-Hee
Title (up) Optimization of MOVPE grown InxAl1-xAs/In0.53Ga0.47As planar heteroepitaxial Schottky diodes for terahertz applications Type Journal Article
Year 1994 Publication IEEE Trans. Electron Devices Abbreviated Journal
Volume 41 Issue 9 Pages 1489-1497
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Notes Approved no
Call Number Serial 253
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Author Karasik, B.S.; Lindgren, M.; Zorin, M.A.; Danerud, M.; Winkler, D.; Trifonov, V.V.; Gol’tsman, G.N.; Gershenzon, E.M.
Title (up) Picosecond detection and broadband mixing of near-infrared radiation by YBaCuO films Type Conference Article
Year 1994 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 2159 Issue Pages 68-76
Keywords YBCO HTS HEB mixer
Abstract Nonequilibrium picosecond and bolometric responses of YBCO films 500 angstroms thick patterned into 20 X 20 micrometers 2 size structure to 17 ps laser pulses and modulated radiation of GaAs and CO2 lasers have been studied. The modulation frequencies up to 10 GHz for GaAs laser and up to 1 GHz for CO2 were attained. The use of small radiation power (1 – 10 mW/cm2 for cw radiation and 10 – 100 nJ/cm2 for pulse radiation) in combination with high sensitive read-out system made possible to avoid any non-linear transient processes caused by an overheating of sample above a critical temperature or S-N switching enhanced by an intense radiation. Responses due to the change of kinetic inductance were believed to be negligible. The only signals observed were caused by a small change of the film resistance either in the resistive state created by a bias current or in the normal state. The data obtained by means of pulse and modulation techniques are in agreement. The responsivity about 1 V/W was measured at 1 GHz modulation frequency both for 0.85 micrometers and 10.6 micrometers wavelengths. The sensitivity of high-Tc fast wideband infrared detector is discussed.
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Publisher Spie Place of Publication Editor Nahum, M.; Villegier, J.-C.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference High-Temperature Superconducting Detectors: Bolometric and Nonbolometric
Notes Approved no
Call Number Serial 1640
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Author Gol'tsman, G.; Jacobsson, S.; Ekstrom, H.; Karasik, B.; Kollberg, E.; Gershenzon, E.
Title (up) Slot-line tapered antenna with NbN hot electron mixer for 300-360 GHz operation Type Conference Article
Year 1994 Publication Proc. 5th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 5th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 209-213a
Keywords NbN HEB mixers
Abstract NbN hot-electron mixers combined with slot-line tapered antennas on Si wdnitride membranes had been fabricated. Several strips of 1 gm wide and 5 tan long made from 100 A NbN film are inserted into the slot antenna. IV-curves under local oscillator power in 300-350 GHz frequency range and conversion gain dependencies on intermediate fre- quency in the 0.1-1 GHz range are measured and compared with that for 100 GHz frequency band. Our results show that pumped IV-curves and intermediate frequency bands are different for 100 GHz and 300 GHz frequency ranges. The interpretation exploits the fact that for the lowest radiation frequency the superconducting energy gap is larger than the radiation quantum energy while they are comparable at the higher frequency. Tha results show that such mixers have good perspectives for terahertz receiving technology.
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Notes Approved no
Call Number Serial 1643
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