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

摘要

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