Aryl Functionalization as a Route to Band Gap Engineering in Single Layer Graphene Devices

TL;DR

This paper demonstrates a scalable chemical functionalization method to tune the electronic properties of single-layer graphene, transforming it from a granular metal to a gapped semiconductor, enabling potential CMOS-compatible device applications.

Contribution

It introduces a non-invasive, scalable functionalization technique that allows precise band gap engineering in graphene by grafting nitrophenyl groups, with tunable electronic properties.

Findings

Functionalized graphene exhibits variable range hopping transport.

Suspended graphene shows a tunable band gap up to 80 meV.

The method is CMOS-compatible and scalable.

Abstract

Chemical functionalization is a promising route to band gap engineering of graphene. We chemically grafted nitrophenyl groups onto exfoliated single-layer graphene sheets in the form of substrate-supported or free-standing films. Our transport measurements demonstrate that non-suspended functionalized graphene behaves as a granular metal, with variable range hopping transport and a mobility gap ~ 0.1 eV at low temperature. For suspended graphene that allows functionalization on both surfaces, we demonstrate tuning of its electronic properties from a granular metal to a gapped semiconductor, in which charge transport occurs via thermal activation over a gap ~ 80 meV. This non-invasive and scalable functionalization technique paves the way for CMOS-compatible band gap engineering of graphene electronic devices.