Surface etching during epitaxial h-BN growth on graphene

The vertically stacked hetero-structure is an important application of two-dimensional materials. In order to avoid contamination during sample transfer and stacking, and to achieve a scalable hexagonal boron nitride (h-BN)/graphene vertical heterostructure, direct growth of a h-BN film on graphene is desirable. However, the growth mechanism of h-BN on graphene is not yet fully understood. Here, we demonstrate the etching growth mechanism of a h-BN film on graphene. X-ray photoemission spectroscopy measurements show the element composition and chemical bonding formation of the pure phase h-BN. Angle-resolved photoemission spectroscopy measurements show the energy dispersion of the h-BN and also reveal the formation of the new R0° graphene. Atomic force microscopy and scanning tunneling microscopy are applied to investigate the surface morphology of the samples. Our study provides a deeper understanding of the growth mechanism of the h-BN film on graphene and shows implication for the further research on h-BN/graphene heterojunctions.