Tunneling Characteristics of NbN/NbN Josephson Junctions with Glow-Discharge-Produced Amorphous Silicon Barriers

Abstract
The tunneling characteristics have been systematically measured for NbN/NbN Josephson tunnel junctions with glow-discharge-produced amorphous silicon layers as tunneling barriers. Junction quality parameters, the junction capacitance and the maximum Josephson current density have been obtained as a function of the thickness of the amorphous silicon layer. It is shown that a significant improvement in tunneling characteristics can be achieved by using an amorphous silicon barrier.