Fabrication of all-NbN Josephson junctions using semiconductive amorphous barriers
Hirotake Yamamori, K Yoshizawa, Akira Fujimaki +1 more
Both underdamped junctions and overdamped junctions utilizing semiconductive amorphous a- barriers have been fabricated by controlling the partial pressure of when the a- barrier is sputtered. While a NbN film is generally used as a superconductive electrode, we have used NbN films for both electrodes and barriers to fabricate overdamped junctions. The films for the barrier are an amorphous semiconductor and have high density of localized states. Typical overdamped junctions have of more than and products of 0.5 mV. On the other hand, typical underdamped junctions have critical current density of to and products of about 1.5 mV. The barrier height of the a- barrier is estimated to be about 0.3 eV from the slope of the barrier thickness dependence of critical current . Then, stacked double barrier junctions have been also fabricated.
Superconductor Science and Technology•Apr 1, 1996•8 citations