Mechanism for current saturation and energy dissipation in graphene transistors

TL;DR

This paper combines theoretical and experimental approaches to demonstrate that substrate and surface optical phonons dominate high-field transport and heat dissipation in graphene transistors, providing insights for improving device performance.

Contribution

It shows that Boltzmann theory with all scattering mechanisms accurately models high electric field transport in graphene transistors without adjustable parameters.

Findings

Surface optical phonons govern high-field transport.

Models neglecting SO phonons are inadequate.

Strategies for higher current and saturation are proposed.

Abstract

From a combination of careful and detailed theoretical and experimental studies, we demonstrate that the Boltzmann theory including all scattering mechanisms gives an excellent account, with no adjustable parameters, of high electric field transport in single as well as double-oxide graphene transistors. We further show unambiguously that scattering from the substrate and superstrate surface optical (SO) phonons governs the high field transport and heat dissipation over a wide range of experimentally relevant parameters. Models that neglect SO phonons altogether or treat them in a simple phenomenological manner are inadequate. We outline possible strategies for achieving higher current and complete saturation in graphene devices.