Giant Intrinsic Carrier Mobilities in Graphene and Its Bilayer

TL;DR

This study demonstrates that graphene and bilayer graphene can achieve extremely high electron mobilities exceeding 200,000 cm2/Vs at room temperature by minimizing extrinsic disorder, with temperature-dependent resistivity explained by rippled sheet models.

Contribution

The paper provides the first detailed analysis of temperature-dependent electron transport in graphene and bilayer, revealing fundamental limits and conditions for ultra-high mobility.

Findings

Electron-phonon scattering rates are extremely low in graphene.

Mobility above 200,000 cm2/Vs is achievable with reduced disorder.

Resistivity increases sharply above 200K due to intra-ripple phonon scattering.

Abstract

We have studied temperature dependences of electron transport in graphene and its bilayer and found extremely low electron-phonon scattering rates that set the fundamental limit on possible charge carrier mobilities at room temperature. Our measurements have shown that mobilities significantly higher than 200,000 cm2/Vs are achievable, if extrinsic disorder is eliminated. A sharp (threshold-like) increase in resistivity observed above approximately 200K is unexpected but can qualitatively be understood within a model of a rippled graphene sheet in which scattering occurs on intra-ripple flexural phonons.