Catalytic Directional Cutting of Hexagonal Boron Nitride: The Roles of Interface and Etching Agents.

Transition-metal (TM) nanoparticle catalyzed cutting has been proven to be an efficient approach to carve out straight channels in graphene to produce high-quality nanoribbons. However, the applicability of such a catalytic approach to hexagonal boron nitride (h-BN) is still an open question due to binary element compositions. Here, our ab initio study indicates that long and straight channels along either the zigzag or the armchair direction of the BN sheet can be carved out, driven by the energetically favored TM-zigzag or TM-armchair BN interface, regardless of roughness of the TM particle surface. Optimal experimental conditions for the catalytic cutting of either BN or BN/graphene hybrid sheet across the domain boundary are proposed via the analysis of the competition between TM-BN (or TM-graphene) interface and H-terminated BN (or graphene) edge. The computation results can serve to guide the experimental design for the production of highly uniform BN (or hybrid BN/graphene) nanoribbons with atomically smooth edges.