Mobility variations in mono- and multi-layer graphene films

TL;DR

This study systematically compares the electrical properties of mono- and multi-layer graphene films, revealing that monolayers have higher mobility but are more sensitive to impurities, highlighting the importance of impurity reduction for high mobility.

Contribution

It provides a detailed analysis of how layer number affects mobility and impurity sensitivity in graphene films, offering insights for optimizing their electronic performance.

Findings

Monolayer graphene exhibits higher carrier mobility than multilayer.

Mobility increases as the number of layers decreases due to reduced interlayer scattering.

Charged impurity density significantly impacts mobility, especially in monolayer graphene.

Abstract

The electric properties of mono- and multi-layer graphene films were systematically studied with the layer number determined by their optical contrast. The current modulation increased monotonically with a decrease in the layer number due to the reduction of the interlayer scattering. Carrier mobility in the monolayer was significantly greater than that in the multilayer due to linear dispersion relation. On the other hand, in the monolayer, carrier transport was extremely sensitive to charged impurity density due to the reduction in screening effect, which causes larger mobility variation. Reduction of the charged impurity density is thus key for high mobility.