Fabrication and characterization of an undoped GaAs/AlGaAs quantum dot device

TL;DR

This paper reports the fabrication and detailed characterization of a tunable undoped GaAs/AlGaAs quantum dot device with integrated charge sensing, demonstrating its potential for future nano-device applications.

Contribution

It introduces a novel double quantum dot device in undoped GaAs/AlGaAs with integrated charge sensing and tunable inter-dot coupling, advancing quantum dot fabrication techniques.

Findings

Quantum dot can be tuned from single to double dot.

Inter-dot coupling is highly tunable via middle gate voltage.

Device shows stability with low potential fluctuation.

Abstract

We demonstrate the development of a double quantum dot with an integrated charge sensor fabricated in undoped GaAs/AlGaAs heterostructures using a double top-gated design. Based on the evaluation of the integrated charge sensor, the double quantum dot can be tuned to a few-electron region. Additionally, the inter-dot coupling of the double quantum dot can be tuned to a large extent according to the voltage on the middle gate. The quantum dot is shown to be tunable from a single dot to a well-isolated double dot. To assess the stability of such design, the potential fluctuation induced by 1/f noise was measured. Based on the findings herein, the quantum dot design developed in the undoped GaAs/AlGaAs semiconductor shows potential for the future exploitation of nano-devices.