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Author Baselmans, J. J. A.; Hajenius, M.; Gao, J.; de Korte, P.; Klapwijk, T. M.; Voronov, B.; Gol’tsman, G. url  doi
openurl 
  Title Doubling of sensitivity and bandwidth in phonon-cooled hot-electron bolometer mixers Type Conference Article
  Year 2004 Publication Proc. SPIE Abbreviated Journal Proc. SPIE  
  Volume 5498 Issue Pages 168-176  
  Keywords Hot electron bolometers, bandwidth, noise temperature, experimental  
  Abstract NbN hot electron bolometer (HEB) mixers are at this moment the best heterodyne detectors for frequencies above 1 THz. However, the fabrication procedure of these devices is such that the quality of the interface between the NbN superconducting film and the contact structure is not under good control. This results in a contact resistance between the NbN bolometer and the contact pad. We compare identical bolometers, with different NbN – contact pad interfaces, coupled with a spiral antenna. We find that cleaning the NbN interface and adding a thin additional superconductor prior to the gold contact deposition improves the noise temperature and the bandwidth of the HEB mixers with more than a factor of 2. We obtain a DSB noise temperature of 950 K at 2.5 THz and a Gain bandwidth of 5-6 GHz. For use in real receiver systems we design small volume (0.15x1 micron) HEB mixers with a twin slot antenna. We find that these mixers combine good sensitivity (900 K at 1.6 THz) with low LO power requirement, which is 160 – 240 nW at the Si lens of the mixer. This value is larger than expected from the isothermal technique and the known losses in the lens by a factor of 3-3.5.  
  Address  
  Corporate Author Thesis  
  Publisher SPIE Place of Publication Editor Zmuidzinas, J.; Holland, W.S.; Withington, S.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference Millimeter and Submillimeter Detectors for Astronomy II  
  Notes Approved no  
  Call Number Serial 1744  
Permanent link to this record
 

 
Author Finkel, M.; Thierschmann, H. R.; Galatro, L.; Katan, A. J.; Thoen, D. J.; de Visser, P. J.; Spirito, M.; Klapwijk, T. M. url  doi
isbn  openurl
  Title Branchline and directional THz coupler based on PECVD SiNx-technology Type Conference Article
  Year 2016 Publication 41st IRMMW-THz Abbreviated Journal 41st IRMMW-THz  
  Volume Issue Pages  
  Keywords microstrip, fixtures, coplanar waveguides, couplers, standards, probes, dielectrics  
  Abstract A fabrication technology to realize THz microstrip lines and passive circuit components is developed and tested making use of a plasma-enhanced chemical vapor deposition grown silicon nitride (PECVD SiNx) dielectric membrane. We use 2 μm thick SiNx and 300 nm thick gold layers on sapphire substrates. We fabricate a set of structures for thru-reflect-line (TRL) calibration, with the reflection standard implemented as a short through the via. We find losses of 9.5 dB/mm at 300 GHz for a 50 Ohm line. For a branchline coupler we measure 2.5 dB insertion loss, 1 dB amplitude imbalance and 21 dB isolation. Good control over the THz lines parameters is proven by similar performance of a set of 5 structures. The directional couplers show -14 dB transmission to the coupled port, -24 dB to the isolated port and -25 dB in reflection. The SiNx membrane, used as a dielectric, is compatible with atomic force microscopy (AFM) cantilevers allowing the application of this technology to the development of a THz near-field microscope.  
  Address  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2162-2035 ISBN 978-1-4673-8485-8 Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number 7758586 Serial 1295  
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Author Gao, J. R.; Hajenius, M.; Baselmans, J. J. A.; Yang, Z. Q.; Baryshev, A. M.; Barends, R.; Klapwijk, T. M.; Voronov, B.; Gol'tsman, G.; Callaos, N. url  isbn
openurl 
  Title Twin-slot antenna coupled NbN hot electron bolometer mixers for space applications Type Conference Article
  Year 2005 Publication Proc. 9-th WMSCI Abbreviated Journal Proc. 9-th WMSCI  
  Volume 9 Issue Pages 148-153  
  Keywords NbN HEB mixers  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher International Institute of Informatics and Systemics Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN 9806560639, 9789806560635 Medium  
  Area Expedition Conference 9th World Multi-Conference on Systemics, Cybernetics and Informatics  
  Notes Approved no  
  Call Number Serial 1480  
Permanent link to this record
 

 
Author Korneeva, Y. P.; Vodolazov, D. Y.; Semenov, A. V.; Florya, I. N.; Simonov, N.; Baeva, E.; Korneev, A. A.; Goltsman, G. N.; Klapwijk, T. M. url  openurl
  Title Optical single photon detection in micron-scaled NbN bridges Type Miscellaneous
  Year 2018 Publication arXiv Abbreviated Journal  
  Volume Issue Pages  
  Keywords SSPD  
  Abstract We demonstrate experimentally that single photon detection can be achieved in micron-wide NbN bridges, with widths ranging from 0.53 μm to 5.15 μm and for photon-wavelengths from 408 nm to 1550 nm. The microbridges are biased with a dc current close to the experimental critical current, which is estimated to be about 50 % of the theoretically expected depairing current. These results offer an alternative to the standard superconducting single-photon detectors (SSPDs), based on nanometer scale nanowires implemented in a long meandering structure. The results are consistent with improved theoretical modelling based on the theory of non-equilibrium superconductivity including the vortex-assisted mechanism of initial dissipation.  
  Address  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Duplicated as 1303 Approved no  
  Call Number Serial 1312  
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Author Yang, Y.; Fedorov, G.; Shafranjuk, S. E.; Klapwijk, T. M.; Cooper, B. K.; Lewis, R. M.; Lobb, C. J.; Barbara, P. url  doi
openurl 
  Title Electronic transport and possible superconductivity at Van Hove singularities in carbon nanotubes Type Journal Article
  Year 2015 Publication Nano Lett. Abbreviated Journal Nano Lett.  
  Volume 15 Issue 12 Pages 7859-7866  
  Keywords carbon nanotubes, CNT, tunable superconductivity, van Hove singularities  
  Abstract Van Hove singularities (VHSs) are a hallmark of reduced dimensionality, leading to a divergent density of states in one and two dimensions and predictions of new electronic properties when the Fermi energy is close to these divergences. In carbon nanotubes, VHSs mark the onset of new subbands. They are elusive in standard electronic transport characterization measurements because they do not typically appear as notable features and therefore their effect on the nanotube conductance is largely unexplored. Here we report conductance measurements of carbon nanotubes where VHSs are clearly revealed by interference patterns of the electronic wave functions, showing both a sharp increase of quantum capacitance, and a sharp reduction of energy level spacing, consistent with an upsurge of density of states. At VHSs, we also measure an anomalous increase of conductance below a temperature of about 30 K. We argue that this transport feature is consistent with the formation of Cooper pairs in the nanotube.  
  Address Department of Physics, Georgetown University , Washington, District of Columbia 20057, United States  
  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 1530-6984 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:26506109; Suuplementary info (attached to pdf) DOI: 10.1021/acs.nanolett.5b02564 Approved no  
  Call Number Serial 1782  
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