Fabrication of uniformly doped graphene quantum Hall arrays with multiple quantized resistance outputs

TL;DR

This paper reports the development of high-quality, uniformly doped graphene quantum Hall arrays with multiple simultaneous quantized resistance outputs, enabling broader dissemination of the ohm over a wide resistance range.

Contribution

It introduces a novel fabrication approach combining large-scale epitaxial graphene and superconducting contacts to create multi-output quantum Hall devices.

Findings

Devices exhibit multiple quantized resistance outputs simultaneously.

Resistance values span from approximately 12.9 kΩ to 1.29 MΩ.

High-quality, centimeter-scale graphene achieved with standard metrological techniques.

Abstract

In this work, limiting factors for developing metrologically useful arrays from epitaxial graphene on SiC are lifted with a combination of centimeter-scale, high-quality material growth and the implementation of superconducting contacts. Standard devices for metrology have been restricted to having a single quantized value output based on the $\nu$ = 2 Landau level. With the demonstrations herein of devices having multiple outputs of quantized values available simultaneously, these versatile devices can be used to disseminate the ohm globally. Such devices are designed to give access to quantized resistance values over the range of three orders of magnitude, starting as low as the standard value of approximately 12.9 k$\Omega$ and reaching as high as 1.29 M$\Omega$. Several experimental methods are used to assess the quality and versatility of the devices, including standard lock-in techniques and Raman spectroscopy.