Multi-carrier Transport in Epitaxial Multi-layer Graphene

TL;DR

This study investigates carrier transport in epitaxial multi-layer graphene, revealing multiple conduction channels with distinct mobilities, especially in C-face grown samples, using variable-field Hall measurements.

Contribution

It introduces a model of three parallel conduction channels in multi-layer graphene, including nearly intrinsic graphene with high mobility, expanding understanding of transport mechanisms.

Findings

Multiple carrier groups with distinct mobilities in C-face MLG

Transport described by three parallel conduction channels

High mobility in nearly intrinsic graphene channel

Abstract

Variable-field Hall measurements were performed on epitaxial graphene grown on Si-face and C-face SiC. The carrier transport involves essentially a single-type of carrier in few-layer graphene, regardless of SiC face. However, in multi-layer graphene (MLG) grown on C-face SiC, the Hall measurements indicated the existence of several groups of carriers with distinct mobilities. Electrical transport in MLG can be properly described by invoking three independent conduction channels in parallel. Two of these are n- and p-type, while the third involves nearly intrinsic graphene. The carriers in this lightly doped channel have significantly higher mobilities than the other two.