Nature of the 1/f Noise in Graphene, Direct Evidence for the Mobility Fluctuations Mechanism

TL;DR

This study provides direct evidence that mobility fluctuations are the primary source of 1/f noise in high-quality graphene, impacting noise reduction strategies in graphene-based electronics.

Contribution

It offers the first direct experimental proof linking mobility fluctuations to 1/f noise in graphene using magnetic field dependence measurements.

Findings

Relative noise spectral density varies non-monotonically with magnetic field.

Minimum noise occurs at a magnetic field where uB=1, indicating mobility fluctuation dominance.

Results clarify the fundamental origin of 1/f noise in graphene and similar electronic materials.

Abstract

The nature of the low-frequency current fluctuations, i.e. carrier number vs. mobility, defines the strategies for noise reduction in electronic devices. While the 1/f noise in metals has been attributed to the electron mobility fluctuations, the direct evidence is lacking (f is the frequency). Here we measured noise in h-BN encapsulated graphene transistor under the condition of geometrical magnetoresistance to directly assess the mechanism of low-frequency electronic current fluctuations. It was found that the relative noise spectral density of the graphene resistance fluctuations depends non-monotonically on the magnetic field (B) with a minimum at approximately uB=1 (u is the electron mobility). This observation proves unambiguously that the mobility fluctuations are the dominant mechanism of the electronic noise in high-quality graphene. Our results are important for all proposed applications of graphene in electronics and add to the fundamental understanding of the 1/f noise origin in any electronic device.