SUBMM heterodyne mixing using NbCN/Nb SIS tunnel junctions.

H vandeStadt*, J Mees, Z Barber, M Blamire, P Dieleman, T deGraauw

*Bijbehorende auteur voor dit werk

    OnderzoeksoutputAcademicpeer review

    7 Citaten (Scopus)

    Samenvatting

    We describe heterodyne mixing experiments with NbCN/Nb quasi-particle tunnel junctions at submillimeter wavelengths. In this wavelength range junctions with niobium nitride as superconducting material are promising because of the high gap voltage, about 5.7 mV, as compared to 3 mV for the more commonly used niobium. As a first step towards all-NbN junctions we investigate the development of junctions with a NbN base electrode and a Nb upper electrode. We present results from samples with two different insulating barriers: aluminum oxide and magnesium oxide. Measured noise temperatures range from 500 K at 345 GHz and 1600 K at 482 GHz to 8500 K at 644 GHz. These results are about one order of magnitude worse than the best results obtained with all-Nb junctions. The difference can be attributed partly to the relatively high radio-frequency (rf) losses in NbN films as compared to Nb. Also sensitivity is reduced because of the relatively high leakage current in the sub-gap region of the I-V curve of the junction.

    Originele taal-2English
    Pagina's (van-tot)91-104
    Aantal pagina's14
    TijdschriftInternational Journal of Infrared and Millimeter Waves
    Volume17
    Nummer van het tijdschrift1
    StatusPublished - jan-1996

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