Analysis of parameters affecting the flicker noise in a two-dimensional electron gas in an AlGaAs/GaAs heterostructure

Abstract

We studied the effect of the most important parameters affecting noise at low frequency in a bi-dimensional electron gas at different temperatures from 300 K down to 4 K, and at two bias voltages (20 and 50 mV). The flicker noise (or 1/f noise) is characterized by the well known Hooge’s expression, and parameters are analyzed; γ increases with the sample length to reach saturation, while α_H presents a linear increase. They also increase with temperature; γ varies linearly independently of the bias, and α_H varies as ~exp(T/T₀) depending on the applied bias. The flicker noise origin is identified as being the carrier mobility fluctuation which is likely dominated by the lattice phonons.