Tunable band gap in few-layer graphene by surface adsorption

TL;DR

This paper proposes a novel method to open and tune the band gap in few-layer graphene using surface adsorption, enabling single-gated FETs with promising electronic properties.

Contribution

It introduces a new approach of single-side metal adsorption to induce band gaps in ABC-stacked FLG, reducing device complexity.

Findings

Band gap size correlates with charge transfer density.

Metal adsorption effectiveness varies: K/Al > Cu/Ag/Au > Pt.

Single-gated Cu-adsorbed FLG FET shows a clear transmission gap.

Abstract

There is a tunable band gap in ABC-stacked few-layer graphene (FLG) via applying a vertical electric field, but the operation of FLG-based field effect transistor (FET) requires two gates to create a band gap and tune channel's conductance individually. Using first principle calculations, we propose an alternative scheme to open a band gap in ABC-stacked FLG namely via single-side adsorption. The band gap is generally proportional to the charge transfer density. The capability to open a band gap of metal adsorption decreases in this order: K/Al > Cu/Ag/Au > Pt. Moreover, we find that even the band gap of ABA-stacked FLG can be opened if the bond symmetry is broken. Finally, a single-gated FET based on Cu-adsorbed ABC-stacked trilayer graphene is simulated. A clear transmission gap is observed, which is comparable with the band gap. This renders metal-adsorbed FLG a promising channel in a single-gated FET device.