High-Quality Hexagonal Boron Nitride Selectively Grown\non Patterned Epigraphene by MOVPE

Hexagonal\nboron nitride encapsulation is the method of choice for\nprotecting graphene from environmental doping and impurity scattering.\nIt was previously demonstrated that metal–organic vapor phase\nepitaxy (MOVPE) grows epitaxially ordered, uniform BN layers on epigraphene\n(graphene grown on SiC). Due to graphene’s nonwetting properties,\nh-BN growth starts preferentially from the graphene ledges. We use\nthis fact here to selectively promote the growth of high-quality flat\nh-BN on epigraphene by patterning epigraphene microstructures prior\nto BN growth. Thin h-BN films (down to 6 nm) grown by MOVPE show a\nsmooth and pleated surface morphology on epigraphene, whereas crumpled\nBN is observed on the SiC. Cross-sectional high-resolution transmission\nelectron microscopy images and fluorescence imaging confirm the higher\nBN quality grown on the epigraphene. Transport measurements reveal\np-doping, as expected from hydrogen intercalation of epigraphene and\nregions of high and low mobility. This method can be used to produce\nstructurally uniform high-quality h-BN/epigraphene micro/nanoscale\nheterostructures.