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| Author | Hajenius, M.; Yang, Z. Q.; Gao, J. R.; Baselmans, J. J. A.; Klapwijk, T. M.; Voronov, B.; Gol'tsman, G. | ||||
| Title | Optimized sensitivity of NbN hot electron bolometer mixers by annealing | Type | Journal Article | ||
| Year | 2007 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
| Volume | 17 | Issue | 2 | Pages | 399-402 |
| Keywords | NbN HEB mixers | ||||
| Abstract | We report that the heterodyne sensitivity of superconducting hot-electron bolometers (HEBs) increases by 25-30% after annealing at 85degC in high vacuum. The devices studied are twin-slot antenna coupled mixers with a small area NbN bridge of 1 mum times 0.15 mum, above which there is a SiO 2 passivation layer. The mixer noise temperature, gain, and resistance versus temperature curve of a HEB before and after annealing are compared and analysed. We show that the annealing reduces the intrinsic noise of the mixer by 37% and makes the superconducting transition of the bridge and the contacts sharper. We argue that the reduction ofthe noise is mainly due to the improvement of the transparency of the contact/film interface. The lowest receiver noise temperature of 700 K is measured at a local oscillator frequency of 1.63 THz and at a bath temperature of 4.2 K. | ||||
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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 | 1426 | |||
| Permanent link to this record | |||||
| Author | Henrich, D.; Dorner,S.; Hofherr, M.; Il'in, K.; Semenov, A.; Heintze, E.; Scheffler, M.; Dressel, M.; Siegel, M. | ||||
| Title | Broadening of hot-spot response spectrum of superconducting NbN nanowire single-photon detector with reduced nitrogen content | Type | Journal Article | ||
| Year | 2012 | Publication | Abbreviated Journal | J. Appl. Phys. | |
| Volume | 112 | Issue | Pages | ||
| Keywords | SSPD, SNSPD, magnetron sputtering, spectrum, NbN film, nitrogen concentration | ||||
| Abstract | The spectral detection efficiency and the dark count rate of superconducting nanowire single-photon detectors (SNSPD) have been studied systematically on detectors made from thin NbN films with different chemical compositions. Reduction of the nitrogen content in the 4 nm thick NbN films results in a decrease of the dark count rates more than two orders of magnitude and in a red shift of the cut-off wavelength of the hot-spot SNSPD response. The observed phenomena are explained by an improvement of uniformity of NbN films that has been confirmed by a decrease of resistivity and an increase of the ratio of the measured critical current to the depairing current. The latter factor is considered as the most crucial for both the cut-off wavelength and the dark count rates of SNSPD. Based on our results we propose a set of criteria for material properties to optimize SNSPD in the infrared spectral region. VC 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757625] |
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| Address | |||||
| Corporate Author | D. Henrich, S. Dorner, M. Hofherr, K. Il'in, A. Semenov, E. Heintze, M. Scheffler, M. Dressel, M. Siegel | Thesis | |||
| Publisher | Place of Publication | Editor | |||
| Language | English | Summary Language | Original Title | Broadening of hot-spot response spectrum of superconducting NbN nanowire single-photon detector with reduced nitrogen content | |
| Series Editor | Series Title | Abbreviated Series Title | |||
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| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | RPLAB @ seleznev @ | Serial | 877 | ||
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| Author | Hübers, H.-W.; Semenov, A. D.; Richter, H.; Schubert, J.; Hadjiloucas, S.; Bowen, J. W.; Gol'tsman, G.; Voronov, B. M.; Gershenzon, E. M. | ||||
| Title | Antenna pattern of the quasi-optical hot-electron bolometric mixer at terahertz frequencies | Type | Conference Article | ||
| Year | 2001 | Publication | Proc. 12th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 12th Int. Symp. Space Terahertz Technol. |
| Volume | Issue | Pages | 286-296 | ||
| Keywords | NbN HEB mixers | ||||
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| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | San Diego, CA, USA | Editor | ||
| Language | Summary Language | Original Title | |||
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| ISSN | ISBN | Medium | |||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 323 | |||
| Permanent link to this record | |||||
| Author | Hübers, H.-W.; Schubert, J.; Krabbe, A.; Birk, M.; Wagner, G.; Semenov, A.; Gol’tsman, G.; Voronov, B.; Gershenzon, E. | ||||
| Title | Parylene anti-reflection coating of a quasi-optical hot-electron-bolometric mixer at terahertz frequencies | Type | Journal Article | ||
| Year | 2001 | Publication | Infrared Physics & Technology | Abbreviated Journal | Infrared Physics & Technology |
| Volume | 42 | Issue | 1 | Pages | 41-47 |
| Keywords | NbN HEB mixers, anti-reflection coating | ||||
| Abstract | Parylene C was investigated as anti-reflection coating for silicon at terahertz frequencies. Measurements with a Fourier-transform spectrometer show that the transmittance of pure silicon can be improved by about 30% when applying a layer of Parylene C with a quarter wavelength optical thickness. The 10% bandwidth of this coating extends from 1.5 to 3 THz for a center frequency of 2.3–2.5 THz, where the transmittance is constant. Heterodyne measurements demonstrate that the noise temperature of a hot-electron-bolometric mixer can be reduced significantly by coating the silicon lens of the hybrid antenna with a quarter wavelength Parylene C layer. Compared to the same mixer with an uncoated lens the improvement is about 30% at a frequency of 2.5 THz. | ||||
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| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1350-4495 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1548 | |||
| Permanent link to this record | |||||
| Author | Hübers, H.-W.; Semenov, A.; Holldack, K.; Schade, U.; Wüstefeld, G.; Gol’tsman, G. | ||||
| Title | Time domain analysis of coherent terahertz synchrotron radiation | Type | Journal Article | ||
| Year | 2005 | Publication | Appl. Phys. Lett. | Abbreviated Journal | Appl. Phys. Lett. |
| Volume | 87 | Issue | 18 | Pages | 184103 (1 to 3) |
| Keywords | NbN HEB mixers, applications | ||||
| Abstract | The time structure of coherent terahertz synchrotron radiation at the electron storage ring of the Berliner Elektronensynchrotron und Speicherring Gesellschaft has been analyzed with a fast superconducting hot-electron bolometer. The emission from a single bunch of electrons was found to last ∼1500ps at frequencies around 0.4THz, which is much longer than the length of an electron bunch in the time domain (∼5ps). It is suggested that this is caused by multiple reflections at the walls of the beam line. The quadratic increase of the power with the number of electrons in the bunch as predicted for coherent synchrotron radiation and the transition from stable to bursting radiation were determined from a single storage ring fill pattern of bunches with different populations. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0003-6951 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1457 | |||
| Permanent link to this record | |||||