Intrinsic and extrinsic origins of low-frequency noise in GaAs/AlGaAs Schottky-gated nanostructures

TL;DR

This study investigates the origins of low-frequency noise in GaAs/AlGaAs quantum devices, revealing that standard fabrication processes suppress gate-dependent noise, and superlattice insertion further reduces trap-related noise, enabling more reliable quantum devices.

Contribution

It demonstrates that standard low-damage fabrication suppresses gate-dependent RTN, and superlattice layers help prevent trap formation, improving device noise performance.

Findings

Standard low-damage process eliminates gate-dependent RTN.

High-damage processes induce charge traps causing RTN.

Superlattice insertion suppresses trap formation.

Abstract

We study low-frequency noise in current passing through quantum point contacts fabricated from several GaAs/AlGaAs heterostructures with different layer structures and fabrication processes. In contrast to previous reports, there is no gate-dependent random telegraph noise (RTN) originating from tunneling through a Schottky barrier in devices fabricated using the standard low-damage process. Gate-dependent RTN appears only in devices fabricated with a high-damage process that induces charge trap sites. We show that the insertion of AlAs/GaAs superlattices in the AlGaAs barrier helps to suppress trap formation. Our results enable the fabrication of damage-resistant and thus low-noise devices.