Metallic single-electron transistor without traditional tunnel barriers

TL;DR

This paper introduces a novel single-electron transistor design using resistive Cr strips instead of traditional tunnel barriers, achieving sharp Coulomb blockade and low cotunneling currents, with potential advantages in noise performance.

Contribution

The study presents a new SET architecture with resistive strips replacing tunnel junctions, demonstrating effective Coulomb blockade and reproducible gate modulation.

Findings

Sharp Coulomb blockade observed

Suppressed cotunneling current at low bias

Noise performance comparable to traditional SETs

Abstract

We report on a new type of single-electron transistor (SET) comprising two highly resistive Cr thin-film strips (~ 1um long) connecting a 1 um-long Al island to two Al outer electrodes. These resistors replace small-area oxide tunnel junctions of traditional SETs. Our transistor with a total asymptotic resistance of 110 kOhm showed a very sharp Coulomb blockade and reproducible, deep and strictly e-periodic gate modulation in wide ranges of bias currents I and gate voltages V_g. In the Coulomb blockade region (|V| < 0.5 mV), we observed a strong suppression of the cotunneling current allowing appreciable modulation curves V-V_g to be measured at currents I as low as 100 fA. The noise figure of our SET was found to be similar to that of typical Al/AlOx/Al single-electron transistors.