High quality superconducting tunnel junctions on Nb and Ta single crystals for radiation detection

M.P. Bruijn, F.B. Kiewiet, M.L. van den Berg, O.J. Luiten, P.A.J. de Korte, A.W. Hamster, G.C.S. Brons, Jakob Flokstra

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6 Citations (Scopus)


High quality Nb/Al-based tunnel junctions, fabricated with a superconducting interface onto thick single crystalx-ray absorbers of Nb and Ta are discussed. Current-voltage characteristics, recorded at 0.5 K, show a subgap current which is still dominated by thermally excited quasiparticles. The quality parameter Rsubgap/Rnormal reaches a value of several million, which is unequalled for nonepitaxially sputtered tunnel junctions. The fabrication process and some development steps, such as preparation of ultrasmooth crystal surfaces are described. Observations of x-ray photons absorbed in Nb and Tasingle crystals detected by the superconducting tunnel junctions are also presented.
Original languageUndefined
Pages (from-to)1252-1254
Number of pages3
JournalApplied physics letters
Issue number9
Publication statusPublished - 1997


  • METIS-129299
  • IR-98128

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