Substitutional mechanism for growth of hexagonal boron nitride on epitaxial graphene

TL;DR

This paper demonstrates a substitutional growth mechanism for monolayer hexagonal boron nitride on graphene on SiC(0001), revealing how h-BN forms by replacing surface graphene and incorporating carbon atoms below as a new graphene layer.

Contribution

It introduces a novel substitutional growth mechanism for h-BN on graphene, supported by low-energy electron microscopy evidence.

Findings

h-BN forms by substituting surface graphene

C atoms are incorporated below h-BN to form a new graphene layer

Grains are ~2 micrometers with a 30-degree orientation

Abstract

Monolayer-thick hexagonal boron nitride (h-BN) is grown on graphene on SiC(0001), by exposure of the graphene to borazine, (BH)3(NH)3, at 1100 C. The h-BN films form ~2-micrometer size grains with a preferred orientation of 30 degrees relative to the surface graphene. Low-energy electron microscopy is employed to provide definitive signatures of the number and composition of two-dimensional (2D) planes across the surface. These grains are found to form by substitution for the surface graphene, with the C atoms produced by this substitution then being incorporated below the h-BN (at the interface between the existing graphene and the SiC) to form a new graphene plane.