Laterally proximized aluminum tunnel junctions

TL;DR

This paper introduces a new fabrication technique for aluminum tunnel junctions that leverages the inverse proximity effect to create high-quality, fully normal-state devices suitable for quantum and electronic applications.

Contribution

It demonstrates a novel method to produce normal metal tunnel junctions with aluminum oxide barriers using lateral proximity effect control, enabling improved device performance.

Findings

Transport characteristics match theoretical models

Fully normal-state devices achieved

Effective suppression of superconductivity in aluminum dots

Abstract

This letter presents experiments on junctions fabricated by a new technique that enables the use of high quality aluminum oxide tunnel barriers with normal metal electrodes at low temperatures. Inverse proximity effect is applied to diminish the superconductivity of an aluminum dot through a clean lateral connection to a normal metal electrode. To demonstrate the effectiveness of this method, fully normal-state single electron transistors (SET) and normal metal-insulator-superconductor (NIS) junctions applying proximized Al junctions were fabricated. The transport characteristics of the junctions were similar to those obtained from standard theoretical models of regular SETs and NIS junctions.