Selective Area Heteroepitaxial Growth of h-BN Micropatterns on Graphene Layers*

Two-dimensional (2D) layers and their heterostructures have great potential for novel electronic and optoelectronic devices due to their remarkable physical properties and interesting behaviors. Accordingly, these 2D nanomaterials have been used in transferable and flexible optoelectronic and electronic devices. Additionally, stacked heterostructures of hexagonal boron nitride (h-BN) and graphene have enabled the fabrication of high-performance electronic devices. Nevertheless, these stacked configurations are still limited by the ability to fabricate h-BN and graphene heterostructures at specific positions. It is crucial for this to be resolved to enable such heterostructures to be exploited as building blocks for fabricating integrated devices.
Here, we report the selective-area heteroepitaxial growth of h-BN on graphene layers using catalyst-free chemical vapor deposition. Focused ion beam technique was used to control the positions of h-BN micropatterns. The crystal structure and microstructural properties of h-BN grown on graphene were investigated using synchrotron radiation X-ray diffraction and transmission electron microscopy, respectively. The catalyst-free growth mechanism is also discussed.