X-ray response of STJ detectors using NbN absorbing layers

We have designed and tested 5 x 5 mm(2) chips containing island type STJs with different geometries, fabricated on Si substrates in the configuration Nb/Al-AlOx/Nb and using a NbN overlayer acting both as wiring and radiation absorber. The aim is to investigate the advantages of the trapping effect...

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Bibliographic Details
Main Authors: Parlato, L, Peluso, G, Pepe, G, diUccio, US, Cristiano, R, Espositio, E, Frunzio, L, Pagano, S, Akoh, H, Nakagawa, H, Takada, S, Gutsche, M, Kraus, H
Format: Conference item
Published: 1996
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Summary:We have designed and tested 5 x 5 mm(2) chips containing island type STJs with different geometries, fabricated on Si substrates in the configuration Nb/Al-AlOx/Nb and using a NbN overlayer acting both as wiring and radiation absorber. The aim is to investigate the advantages of the trapping effect due to the Nb layer trap. In fact, for the NbN/Nb bilayer the scattering time is much faster than the values calculated for other Nb based bilayers, leading to more efficient trapping processes. The junctions have been characterized by tunneling and Josephson current measurements down to 0.5 K. Experimental results concerning the response of the devices under X-ray irradiation down to 60 mK are presented and discussed.