Mobility-dependent Low-frequency Noise in Graphene Field Effect Transistors

TL;DR

This study examines how low-frequency 1/f noise in graphene transistors depends on mobility and temperature, revealing a universal relation between noise and mobility and highlighting the impact of disorder dynamics.

Contribution

It introduces a generalized Hooge's relation for graphene transistors, showing the Hooge parameter varies with mobility and disorder, which is a novel insight.

Findings

Noise amplitude decreases with mobility away from the Dirac point.

Suspended graphene exhibits lower 1/f noise than on-substrate graphene.

The Hooge parameter is sample and temperature independent, but varies with disorder.

Abstract

We have investigated the low-frequency 1/f noise of both suspended and on-substrate graphene field-effect transistors and its dependence on gate voltage, in the temperature range between 300K and 30K. We have found that the noise amplitude away from the Dirac point can be described by a generalized Hooge's relation in which the Hooge parameter {\alpha}H is not constant but decreases monotonically with the device's mobility, with a universal dependence that is sample and temperature independent. The value of {\alpha}H is also affected by the dynamics of disorder, which is not reflected in the DC transport characteristics and varies with sample and temperature. We attribute the diverse behavior of gate voltage dependence of the noise amplitude to the relative contributions from various scattering mechanisms, and to potential fluctuations near the Dirac point caused by charge carrier inhomogeneity. The higher carrier mobility of suspended graphene devices accounts for values of 1/f noise significantly lower than those observed in on-substrate graphene devices and most traditional electronic materials.