From low-bias mobility to high-bias current saturation: fundamental trade-offs in graphene based transistors

TL;DR

This paper explores the fundamental physical trade-offs in graphene-based transistors, showing that mobility, current saturation, and ON-OFF ratios are constrained by intrinsic bandstructure properties, independent of scattering.

Contribution

It reveals that these trade-offs are governed by an asymptotic bandstructure constraint, unifying various graphene derivatives on a common mobility-bandgap-scattering length framework.

Findings

Trade-offs arise solely from high energy bandstructure constraints.

Graphene derivatives are positioned on a unified 3-parameter plot.

High bias current signatures depend on saturation mechanisms.

Abstract

We describe the fundamental trade-offs in engineering the mobility, current saturation and ON- OFF ratios in graphene transistors. Surprisingly, the trade-offs arise solely from an asymptotic constraint on the high energy bandstructure and independent of scattering processes. This places graphite derivatives (bulk monolayer graphene, uniaxially strained graphene nanoribbons, carbon nanotubes and bilayer graphene) on the same 3-parameter mobility-bandgap-scattering length ({\mu} - Egap -{\lambda}) plot, proximal to other semiconductors. In addition to this low-bias trade-off, the high bias current bears signatures of the underlying saturation mechanism, arising through phonon scattering or {\Gamma}-point suppressed density of states opening bandgap.