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Circuit with small-capacitance high-quality Nb Josephson junctions

Michio Watanabe·Yasunobu Nakamura·Jaw-Shen Tsai
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Abstract

We have developed a fabrication process for nanoscale tunnel junctions which includes focused-ion-beam etching from different directions. By applying the process to a Nb/(Al-)Al_2O_3/Nb trilayer, we have fabricated a Nb single-electron transistor (SET), and characterized the SET at low temperatures, T=0.04-40 K. The superconducting gap energy and the transition temperature of the Nb SET agree with the bulk values, which suggests high quality Nb junctions. The single-electron charging energy of the SET is estimated to be larger than 1 K.

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Michio Watanabe, Yasunobu Nakamura, Jaw-Shen Tsai. 2004-01-16. Circuit with small-capacitance high-quality Nb Josephson junctions. https://doi.org/10.1063/1.1640798

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