Modulation of Noise in Submicron GaAs/AlGaAs Hall Devices by Gating

TL;DR

This study systematically characterizes noise fluctuations in submicron GaAs/AlGaAs Hall devices, demonstrating how gating can significantly reduce noise levels while affecting carrier density and impurity-related switching processes.

Contribution

It provides a detailed analysis of noise spectra modulation in GaAs/AlGaAs Hall devices through gating and temperature variation, highlighting impurity-related switching mechanisms.

Findings

Noise spectra vary from 1/f to Lorentzian types.

Gate voltage reduces noise by several orders of magnitude.

Noise dependence on temperature and gate voltage explained by impurity switching.

Abstract

We present a systematic characterization of fluctuations in submicron Hall devices based on GaAs/AlGaAs two-dimensional electron gas heterostructures at temperatures between 1.5 K to 60 K. A large variety of noise spectra, from 1/f to Lorentzian, are obtained by gating the Hall devices. The noise level can be reduced by up to several orders of magnitude with a moderate gate voltage of 0.2 V, whereas the carrier density increases less than 60% in the same range. The significant dependence of the Hall noise spectra on temperature and gate voltage is explained in terms of the switching processes related to impurities in n-AlGaAs.