1/f noise as a probe for investigating band structure in graphene

TL;DR

This paper demonstrates that flicker noise measurements can effectively distinguish between linear and parabolic band structures in graphene, providing a simple method to identify single-layer versus multilayer graphene.

Contribution

It introduces flicker noise as a sensitive and robust probe for graphene's band structure, applicable across different device types and disorder levels.

Findings

Flicker noise varies with carrier density differently for linear and parabolic bands.

The noise-based method reliably distinguishes single-layer from multilayer graphene.

The approach is robust against disorder and substrate effects.

Abstract

A distinctive feature of single layer graphene is the linearly dispersive energy bands, which in case of multilayer graphene become parabolic. Other than the quantum Hall effect, this distinction has been hard to capture in electron transport. Carrier mobility of graphene has been scrutinized, but many parallel scattering mechanisms often obscure its sensitivity to band structure. The flicker noise in graphene depends explicitly on its ability to screen local potential fluctuations. Here we show that the flicker noise is a sensitive probe to the band structure of graphene that vary differently with the carrier density for the linear and parabolic bands. Using devices of different genre, we find this difference to be robust against disorder in the presence or absence of substrate. Our results reveal the microscopic mechanism of noise in Graphene Field Effect Transistors (GraFET), and outline a simple portable method to separate the single from multi layered devices.