Systematic Investigation of the Intrinsic Channel Properties and Contact Resistance of Monolayer and Multilayer Graphene FET

TL;DR

This study systematically examines the intrinsic electrical properties and contact resistance of monolayer and multilayer graphene FETs, revealing how layer number influences band overlap and contact resistivity, with implications for device performance.

Contribution

It provides a comprehensive analysis of how layer number affects intrinsic properties and contact resistance in graphene FETs, highlighting the role of band overlap and contact resistivity.

Findings

Band overlap increases from 1 meV in bilayer to 40 meV in graphite.

Monolayer graphene shows unique temperature dependence due to linear dispersion.

Contact resistivity varies from 10^3 to 10^6 Ohm micron, affecting device performance.

Abstract

The intrinsic channel properties of monolayer and multilayer graphene were systematically investigated as a function of layer number by the exclusion of contact resistance using four-probe measurements. We show that the continuous change in normalized sheet resistivity from graphite to a bilayer graphene is governed by one unique property, i.e., the band overlap, which markedly increases from 1 meV for a bilayer graphene to 11 meV for eight layers and eventually reaches 40 meV for graphite. The monolayer graphene, however, showed a deviation in temperature dependence due to a peculiar linear dispersion. Additionally, contact resistivity was extracted for the case of typical Cr/Au electrodes. The observed high contact resistivity, which varies by three orders of magnitude (from ~103 to 106 Ohm micron), might significantly mask the outstanding performance of the monolayer graphene channel, suggesting its importance in future research.