Impurities as a source of flicker noise in graphene

TL;DR

This paper investigates how impurities, especially water, influence flicker noise in graphene, revealing that different scattering mechanisms cause distinct noise behaviors and that water acts as a long-range scatterer increasing noise.

Contribution

It demonstrates experimentally that impurities, notably water, significantly affect flicker noise in graphene by altering scattering mechanisms, providing insights into noise sources.

Findings

Water increases flicker noise magnitude in graphene.

Different scattering mechanisms cause distinct noise behaviors.

Water acts as a long-range scatterer in graphene.

Abstract

We experimentally study the effect of different scattering potentials on the flicker noise observed in graphene devices on silica substrates. The noise in nominally identical devices is seen to behave in two distinct ways as a function of carrier concentration, changing either monotonically or nonmonotonically. We attribute this to the interplay between long- and short-range scattering mechanisms. Water is found to significantly enhance the noise magnitude and change the type of the noise behaviour. By using a simple model, we show that water is a source of long-range scattering.