Optical Spectroscopic Study of AlN-Based SIS Devices Grown by Inductively Coupled Plasma

High-quality Nb-based superconductor-insulator-superconductor (SIS) junctions with aluminum oxide tunnel barriers grown from Al overlayers are broadly reported in the literature. However, as the current density increases, aluminum oxide tunnel barriers yield significant leakage current due to the pinholes and defects in the tunnel barrier. In this work, the growth dynamics of AlN are studied throu...