Theoretical analysis of high-field transport in graphene on a substrate

TL;DR

This paper presents a comprehensive theoretical analysis of high-field charge transport in substrate-supported graphene, highlighting the dominant scattering mechanisms and the impact of substrate thermal properties on drift velocity.

Contribution

It introduces a hydrodynamic model incorporating self-heating, substrate coupling, and various scattering processes to analyze high-field transport in graphene on different dielectrics.

Findings

High-field transport is mainly influenced by interfacial plasmon-phonon modes.

Lattice heating can cause negative differential drift velocity.

Graphene on BN achieves the highest high-field drift velocity.

Abstract

We investigate transport in graphene supported on various dielectrics (SiO2, BN, Al2O3, HfO2) through a hydrodynamic model which includes self-heating and thermal coupling to the substrate, scattering with ionized impurities, graphene phonons and dynamically screened interfacial plasmon-phonon (IPP) modes. We uncover that while low-field transport is largely determined by impurity scattering, high-field transport is defined by scattering with dielectric-induced IPP modes, and a smaller contribution of graphene intrinsic phonons. We also find that lattice heating can lead to negative differential drift velocity (with respect to the electric field), which can be controlled by changing the underlying dielectric thermal properties or thickness. Graphene on BN exhibits the largest high-field drift velocity, while graphene on HfO2 has the lowest one due to strong influence of IPP modes.