Bonding characteristics of the interfacial buffer layer in epitaxial graphene via density functional theory

TL;DR

This study uses density functional theory to analyze the bonding properties of the interfacial buffer layer in epitaxial graphene on SiC, revealing how covalent bonds and lattice mismatch influence the interface structure.

Contribution

It provides detailed insights into the bonding characteristics and periodicity of the buffer layer in epitaxial graphene, highlighting the role of lattice mismatch.

Findings

Identified covalent anchor points at the interface.

Determined the periodic length between covalent bonds.

Showed dependence of anchor point formation on lattice mismatch.

Abstract

Monolayer epitaxial graphene is an appropriate candidate for a wide variety of electronic and optical applications. One advantage of growing graphene on the Si face of SiC is that it develops as a single crystal, as does the layer underneath, commonly referred to as the interfacial buffer layer. The properties of this supporting layer include a band gap, making it of interest to groups seeking to build devices with on-off capabilities. In this work, using density functional theory, we have calculated the bonding characteristics of the buffer layer to the SiC substrate beneath. These calculations were used to determine a periodic length between the covalent bonds acting as anchor points in this interface. Additionally, it is evident that the formation of these anchor points depends on the lattice mismatch between the graphene layer and SiC.