Interfacial and Electronic Properties of Heterostructures of MXene and Graphene

TL;DR

This study uses density functional theory to analyze the interfacial and electronic properties of MXene-graphene heterostructures, revealing how surface groups, stacking order, and work function differences influence charge transfer, band structure, and interfacial adhesion.

Contribution

It provides a detailed first-principles analysis of how surface functionalization and stacking configurations affect MXene-graphene heterostructures, offering insights into their electronic interactions.

Findings

Charge transfer depends on work function differences.

Stacking order influences band gap opening in bilayer graphene.

Interfacial adhesion is affected by surface functional groups.

Abstract

MXene-based heterostructures have received considerable interest owing to their unique properties. Herein, we examine various heterostructures of a prototypical MXene and graphene using density functional theory. We find that the adhesion energy, charge transfer, and band structure of these heterostructures are sensitive not only to the surface functional group, but also to the stacking order. Difference in work function dictates the direction and amount of electron transfer across the interface, which causes a shift in the Dirac point of the graphene bands in the heterostructures of monolayer graphene and monolayer MXene. In the heterostructures of bilayer graphene and monolayer MXene, the interface breaks the symmetry of the bilayer graphene; in the case of the AB-stacking bilayer, the electron transfer leads to an interfacial electric field that opens up a gap in the graphene bands at the K point. This internal polarization strengthens both the interfacial adhesions and the cohesion between the two graphene layers. The MXene-graphene-MXene and graphene-MXene-graphene sandwich structures behave as two mirror-symmetric MXene-graphene interfaces. Our first principles studies provide a comprehensive understanding for the interaction between a typical MXene and graphene.