Low-Leakage Superconducting Tunnel Junctions with a Single-Crystal Al2O3 Barrier

Published

September 5, 2005

Author(s)

Seongshik Oh, Katarina Cicak, Kevin Osborn, Raymond Simmonds, David P. Pappas, Robert Mcdermott, Ken B. Cooper, Matthias Steffen, John M. Martinis

Abstract

We have developed a two-step growth scheme for single-crystal Al2O3 tunnel barriers. The barriers are epitaxially grown on single-crystal rhenium (Re) base electrodes that are grown epitaxially on a sapphire substrate, while polycrystalline Al is used as the top electrode. We show that, by first growing an amorphous Al oxide layer at room temperature and crystallizing it at a high temperature in oxygen environment, a morphologically intact single-crystal Al2O3 layer is obtained. Tunnel junctions fabricated from these trilayers show very low subgap leakage current with a quality factor of 1200. This leakage-free single-crystal Al2O3 junction has opened a new venue for coherent quantum devices.

Citation

Superconductor Science and Technology

Volume

18

Issue

10

Pub Type

Journals

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Keywords

Al2O3, Epitaxy, Tunnel Junction

Citation

Oh, S. , Cicak, K. , Osborn, K. , Simmonds, R. , Pappas, D. , Mcdermott, R. , Cooper, K. , Steffen, M. and Martinis, J. (2005), Low-Leakage Superconducting Tunnel Junctions with a Single-Crystal Al2O3 Barrier, Superconductor Science and Technology, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=32036 (Accessed October 24, 2025)