Effect of high-k environment on charge carrier mobility in graphene

TL;DR

This study investigates how different substrates and high-k dielectric environments affect charge carrier mobility in graphene, challenging the assumption that Coulomb impurities are the main scattering source.

Contribution

The paper provides experimental evidence that Coulomb impurities are not the primary factor limiting graphene's mobility, even in high-k dielectric environments.

Findings

No significant mobility change with different substrates.

Glycerol, ethanol, and water do not alter mobility.

Coulomb impurities are unlikely the dominant scattering mechanism.

Abstract

It is widely assumed that the dominant source of scattering in graphene is charged impurities in a substrate. We have tested this conjecture by studying graphene placed on various substrates and in high-k media. Unexpectedly, we have found no significant changes in carrier mobility either for different substrates or by using glycerol, ethanol and water as a top dielectric layer. This suggests that Coulomb impurities are not the scattering mechanism that limits the mean free path currently attainable for graphene on a substrate.