Low-leakage superconducting tunnel junctions with a single-crystal Al2O3barrier

作者：Seongshik Oh, Katarina Cicak, R. McDermott, Ken B. Cooper, Kevin D. Osborn, Raymond W. Simmonds, Matthias Steffen, John M. Martinis, David P. Pappas · 发表于：Superconductor Science and Technology · 年份：2005 · DOI：10.1088/0953-2048/18/10/026 · 被引用次数：27 · 研究领域：Quantum and electron transport phenomena、Semiconductor materials and devices、Physics of Superconductivity and Magnetism

We have developed a two-step growth scheme for single-crystal Al 2 O 3 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 aluminium (Al) oxide layer at room temperature and crystallizing it at a high temperature in oxygen environment, a morphologically intact single-crystal Al 2 O 3 layer is obtained. Tunnel junctions fabricated from these trilayers show very low subgap leakage current. This single-crystal Al 2 O 3 junction may open a new venue for coherent quantum devices.