Effect of growth conditions on the electrical properties of Nb/Al-oxide/Nb tunnel junctions

The influence of oxygen exposure and substrate temperature during crystal growth on the critical current density and resistivity of Nb/AlOx/Nb Josephson tunnel junctions is investigated at low- and high-exposure regimes. Results show that oxygen exposure affects the junctions' electric properties at the low exposure regime. For high exposure, the tunnel junctions' electric properties are strongly dependent on the substrate temperature.