High-quality hexagonal boron nitride selectively grown on patterned epigraphene by MOVPE

TL;DR

This paper demonstrates a method to selectively grow high-quality hexagonal boron nitride on patterned epigraphene using MOVPE, enabling the fabrication of uniform 2D heterostructures with potential electronic applications.

Contribution

It introduces a patterning technique that promotes selective, high-quality h-BN growth on epigraphene, improving heterostructure fabrication.

Findings

High-quality h-BN films down to 6 nm were grown on epigraphene.

Selective growth was achieved on patterned microstructures.

Transport measurements showed p-doping and variable mobility.

Abstract

Hexagonal boron nitride encapsulation is the method of choice for protecting graphene from environmental doping and impurity scattering. It was previously demonstrated that metal-organic vapor phase epitaxy (MOVPE) grows epitaxially ordered, uniform BN layers on epigraphene (graphene grown on SiC). Due to graphene non-wetting properties, h-BN growth starts preferentially from the graphene ledges. We use this fact here to selectively promote growth of high-quality flat h-BN on epigraphene by patterning epigraphene microstructures prior to BN growth. Thin h-BN films (down to 6 nm) grown by MOVPE show smooth and pleated surface morphology on epigraphene, while crumpled BN is observed on the SiC. Cross-sectional high-resolution transmission electron microscopy images and fluorescence imaging confirm the higher BN quality grown on the epigraphene. Transport measurements reveal p-doping as expected from hydrogen intercalation of epigraphene and regions of high and low mobility. This method can be used to produce structurally uniform high-quality h-BN/epigraphene micro/nano scale heterostructure.