Dynamic observation of in-plane h-BN/graphene heterostructures growth on Ni(111)

The lateral incorporation of graphene and hexagonal boron nitride (h-BN) onto a substrate surface creates in-plane h-BN/graphene heterostructures, which have promising applications in novel two-dimensional electronic and photoelectronic devices. The quality of h-BN/graphene domain boundaries depends on their orientation, which is crucial for device performances. Here, the heteroepitaxial growth of graphene along the edges of h-BN domains on Ni(111) surfaces as well as the growth dynamics of h-BN using chemical vapor deposition (CVD) are in situ investigated by surface imaging measurements. The nucleating seed effect of h-BN has been revealed, which contributes to the single orientation of heterostructures with epitaxial stitching. Further, the growth of h-BN prior to that of graphene is essential to obtain high-quality in-plane h-BN/graphene heterostructures on Ni(111). The "compact to fractal" shape transition of h-BN domains appears with the increasing surface concentration of the growth blocks, suggesting that the dynamic growth mechanism follows diffusion-limited aggregation (DLA) but not reaction-limited aggregation (RLA). Our results provide insights into the synthesis of well-defined h-BN/graphene heterostructures and deep understanding of the growth dynamics of h-BN on metal surfaces.