Robust formation of quantum dots in GaAs/AlGaAs heterostructures for single-electron metrology

Abstract

The robust and reproducible formation of a quantum dot is key for the development of tunable barrier single-electron pumps as a future quantum current standard. We investigate the fabrication process and perform electrical characterizations at cryogenic temperatures of quantum dots realized in a GaAs/AlGaAs heterostructure with lateral potential confinement by a combination of a shallow-etch technique and metallic top-gates. Stable geometric parameters of the lithography (5% deviation) in combination with a homogeneous heterostructure resulted in the robust and reproducible quantum dot formation for 37 out of 39 tested devices.