All-refractive light-sensitive tunnel junctions employing different multilayer configurations

Ligth-sensitive semiconducting films as barrier are a feasible tool to modify the tunneling behavior of superconducting junctions during the experiments. II-VI compounds have been demonstrated to be suitable to such a purpose, their fabrication procedure being compatible with all refractory Josephson junction technology. Experiments performed on light-sensitive Josephson tunnel junctions have shown the relevant role of the metal/semiconductor interfaces in determining their transport properties. Different kind of all refractory Nb/Nb junctions have been fabricated involving CdS thin film in a sandwich-type structure. Both symmetric and asymmetric multilayers (Nb-N-CdS-N-Nb, Nb-N-CdS-Nb) have been considered using different normal layers N (Al, In). The effect of the N-layer on the current-voltage (I-V), (dI/dV)-V characteristics and on the light-sensitive behavior of the junctions is discussed. © 2002 Elsevier Science B.V. All rights reserved.