Superconducting tantalum nitride-based normal metal-insulator-superconductor tunnel junctions

Abstract

We report the development of superconducting tantalum nitride (TaN${}_x$) normal metal-insulator-superconductor (NIS) tunnel junctions. For the insulating barrier, we used both AlO${}_x$ and TaO${}_x$ (Cu-AlO${}_x$-Al-TaN${}_x$ and Cu-TaO${}_x$-TaN${}_x$), with both devices exhibiting temperature dependent current-voltage characteristics which follow the simple one-particle tunneling model. The superconducting gap follows a BCS type temperature dependence, rendering these devices suitable for sensitive thermometry and bolometry from the superconducting transition temperature $T_{\text{C}}$ of the TaN${}_x$ film at $\sim 5$ K down to $\sim$ 0.5 K. Numerical simulations were also performed to predict how junction parameters should be tuned to achieve electronic cooling at temperatures above 1 K.

Appl. Phys. Lett. in press

References in corpus (4)

• Micrometre-scale refrigerators
• Are pinholes the cause of excess current in superconducting tunnel junctions? A study of Andreev current in highly resistive junctions
• Phonon cooling of nanomechanical beams with tunnel junctions
• Sub-micron normal-metal/insulator/superconductor tunnel junction thermometer and cooler using Nb

Cited by in corpus (4)

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• Efficient electronic cooling above 2 K by niobium-based superconducting tunnel junctions
• Excess quasiparticles and their dynamics in the presence of subgap states
• Highly tunable NbTiN Josephson junctions fabricated with focused helium ion beam