Impact of silicon doping on low frequency charge noise and conductance drift in GaAs/AlGaAs nanostructures

TL;DR

This study investigates how varying silicon doping levels in GaAs/AlGaAs heterostructures affects low frequency charge noise and conductance drift, revealing that lower doping reduces noise and drift, highlighting the role of neutral doping regions.

Contribution

It provides experimental evidence that reducing silicon doping density decreases charge noise and conductance drift in GaAs/AlGaAs nanostructures, emphasizing the importance of neutral doping regions.

Findings

Lower doping density reduces charge noise.

Decreased doping lessens conductance drift.

Neutral doping regions significantly influence noise and drift.

Abstract

We present measurements of low frequency charge noise and conductance drift in modulation doped GaAs/AlGaAs heterostructures grown by molecular beam epitaxy in which the silicon doping density has been varied from $2.4\times 10^{18} cm^{-3}$ (critically doped) to $6.0\times 10^{18} cm^{-3}$ (overdoped). Quantum point contacts were used to detect charge fluctuations. A clear reduction of both short time scale telegraphic noise and long time scale conductance drift with decreased doping density was observed. These measurements indicate that the {\it neutral} doping region plays a significant role in charge noise and conductance drift.