Cryogenic on-chip multiplexer for the study of quantum transport in 256 split-gate devices

TL;DR

This paper introduces a cryogenic on-chip multiplexer enabling individual measurement of 256 mesoscopic devices, significantly enhancing scalability and measurement efficiency in quantum transport studies at cryogenic temperatures.

Contribution

The paper presents a scalable multiplexing architecture for cryogenic measurements, allowing individual access to 256 split-gate devices on a single chip, improving measurement throughput and device yield.

Findings

Achieved 94% fabrication yield for the device array.

Quantum yield increased from 55% to 86% after illumination.

Demonstrated scalability of the multiplexer architecture.

Abstract

We present a multiplexing scheme for the measurement of large numbers of mesoscopic devices in cryogenic systems. The multiplexer is used to contact an array of 256 split gates on a GaAs/AlGaAs heterostructure, in which each split gate can be measured individually. The low-temperature conductance of split-gate devices is governed by quantum mechanics, leading to the appearance of conductance plateaux at intervals of 2e^2/h. A fabrication-limited yield of 94% is achieved for the array, and a "quantum yield" is also defined, to account for disorder affecting the quantum behaviour of the devices. The quantum yield rose from 55% to 86% after illuminating the sample, explained by the corresponding increase in carrier density and mobility of the two-dimensional electron gas. The multiplexer is a scalable architecture, and can be extended to other forms of mesoscopic devices. It overcomes previous limits on the number of devices that can be fabricated on a single chip due to the number of electrical contacts available, without the need to alter existing experimental set ups.