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| Author | Trifonov, A.; Tong, C.-Y. E.; Lobanov, Y.; Kaurova, N.; Blundell, R.; Goltsman, G. | ||||
| Title | Photon absorption near the gap frequency in a hot electron bolometer | Type | Journal Article | ||
| Year | 2017 | Publication  |
IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
| Volume | 27 | Issue | 4 | Pages | 1-4 |
| Keywords | NBN HEB mixer | ||||
| Abstract | The superconducting energy gap is a fundamental characteristic of a superconducting film, which, together with the applied pump power and the biasing setup, defines the instantaneous resistive state of the Hot Electron Bolometer (HEB) mixer at any given bias point on the I-V curve. In this paper we report on a series of experiments, in which we subjected the HEB to radiation over a wide frequency range along with parallel microwave injection. We have observed three distinct regimes of operation of the HEB, depending on whether the radiation is above the gap frequency, far below it or close to it. These regimes are driven by the different patterns of photon absorption. The experiments have allowed us to derive the approximate gap frequency of the device under test as about 585 GHz. Microwave injection was used to probe the HEB impedance. Spontaneous switching between the superconducting (low resistive) state and a quasi-normal (high resistive) state was observed. The switching pattern depends on the particular regime of HEB operation and can assume a random pattern at pump frequencies below the gap to a regular relaxation oscillation running at a few MHz when pumped above the gap. | ||||
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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 | 1331 | |||
| Permanent link to this record | |||||
| Author | Krause, S.; Mityashkin, V.; Antipov, S.; Gol’tsman, G.; Meledin, D.; Desmaris, V.; Belitsky, V.; Rudziński, M. | ||||
| Title | Reduction of phonon escape time for nbn hot electron bolometers by using gan buffer layers | Type | Journal Article | ||
| Year | 2017 | Publication |
IEEE Trans. Terahertz Sci. Technol. | Abbreviated Journal | IEEE Trans. Terahertz Sci. Technol. |
| Volume | 7 | Issue | 1 | Pages | 53-59 |
| Keywords | NbN HEB mixer | ||||
| Abstract | In this paper, we investigated the influence of the GaN buffer layer on the phonon escape time of phonon-cooled hot electron bolometers (HEBs) based on NbN material and compared our findings to conventionally employed Si substrate. The presented experimental setup and operation of the HEB close to the critical temperature of the NbN film allowed for the extraction of phonon escape time in a simplified manner. Two independent experiments were performed at GARD/Chalmers and MSPU on a similar experimental setup at frequencies of approximately 180 and 140 GHz, respectively, and have shown reproducible and consistent results. By fitting the normalized IF measurement data to the heat balance equations, the escape time as a fitting parameter has been deduced and amounts to 45 ps for the HEB based on Si substrate as in contrast to a significantly reduced escape time of 18 ps for the HEB utilizing the GaN buffer layer under the assumption that no additional electron diffusion has taken place. This study indicates a high phonon transmissivity of the NbN-to-GaN interface and a prospective increase of IF bandwidth for HEB made of NbN on GaN buffer layers, which is desirable for future THz HEB heterodyne receivers. | ||||
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| Language | Summary Language | Original Title | |||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 2156-3446 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1330 | |||
| Permanent link to this record | |||||
| 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 | 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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| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 2156-342X | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1292 | |||
| Permanent link to this record | |||||
| Author | Finkel, M.; Thierschmann, H.; Galatro, L.; Katan, A. J.; Thoen, D. J.; de Visser, P. J.; Spirito, M.; Klapwijk, T. M. | ||||
| Title | Performance of THz components based on microstrip PECVD SiNx technology | Type | Journal Article | ||
| Year | 2017 | Publication |
IEEE Trans. THz Sci. Technol. | Abbreviated Journal | IEEE Trans. THz Sci. Technol. |
| Volume | 7 | Issue | 6 | Pages | 765-771 |
| Keywords | transmission line measurements, power transmission lines, dielectrics, couplers, submillimeter wave circuits, coplanar waveguides, micromechanical devices | ||||
| Abstract | We present a performance analysis of passive THz components based on Microstrip transmission lines with a 2-μmthin plasma-enhanced chemical vapor deposition grown silicon nitride (PECVD SiNX) dielectric layer. A set of thru-reflect-line calibration structures is used for basic transmission line characterizations. We obtain losses of 9 dB/mm at 300 GHz. Branchline hybrid couplers are realized that exhibit 2.5-dB insertion loss, 1-dB amplitude imbalance, and -26-dB isolation, in agreement with simulations. We use the measured center frequency to determine the dielectric constant of the PECVD SiN x , which yields 5.9. We estimate the wafer-to-wafer variations to be of the order of 1%. Directional couplers are presented which exhibit -12-dB transmission to the coupled port and -26 dB to the isolated port. For transmission lines with 5-μm-thin silicon nitride (SiN x ), we observe losses below 4 dB/mm. The thin SiN x dielectric membrane makes the THz components compatible with scanning probe microscopy cantilevers allowing the application of this technology in on-chip circuits of a THz near-field microscope. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 2156-342X | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 1294 | |||
| Permanent link to this record | |||||
| Author | Korneeva, Yuliya; Florya, Irina; Vdovichev, Sergey; Moshkova, Mariya; Simonov, Nikita; Kaurova, Natalia; Korneev, Alexander; Goltsman, Gregory | ||||
| Title | Comparison of hot-spot formation in NbN and MoN thin superconducting films after photon absorption | Type | Conference Article | ||
| Year | 2017 | Publication |
IEEE Transactions on Applied Superconductivity | Abbreviated Journal | IEEE Transactions on Applied Superconductiv |
| Volume | 27 | Issue | 4 | Pages | 5 |
| Keywords | Thin film devices, Superconducitng photoncounting devices, Nanowire single-photon detectors | ||||
| Abstract | In superconducting single-photon detectors SSPD the efficiency of local suppression of superconductivity and hotspot formation is controlled by diffusivity and electron-phonon interaction time. Here we selected a material, 3.6-nm-thick MoNx film, which features diffusivity close to those of NbN traditionally used for SSPD fabrication, but with electron-phonon interaction time an order of magnitude larger. In MoNx detectors we study the dependence of detection efficiency on bias current, photon energy, and strip width and compare it with NbN SSPD. We observe non-linear current-energy dependence in MoNx SSPD and more pronounced plateaus in dependences of detection efficiency on bias current which we attribute to longer electronphonon interaction time. |
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| Notes | Approved | no | |||
| Call Number | RPLAB @ kovalyuk @ | Serial | 1114 | ||
| Permanent link to this record | |||||