Controlled Growth of Unidirectionally Aligned Hexagonal Boron Nitride Domains on Single Crystal Ni (111)/MgO Thin Films

Abstract

Two-dimensional (2D) hexagonal boron nitride (h-BN) is considered as an ideal dielectric layer or substrate for other 2D heterostructure electronic devices. However, reported 2D h-BN films consist mostly of small sized and randomly oriented h-BN domains, resulting in a high density of grain boundaries during coalescence. Here, we report the growth of unidirectionally aligned h-BN domains in a large area on the Ni(111) epitaxial thin film on MgO(111) substrate by ion beam sputtering deposition. It is found that the in-plane orientation of the underlying Ni thin film, which can be controlled by its deposition temperature, plays a key role in the h-BN domain alignment. Furthermore, density functional theory calculations are performed to determine the favorable configuration of the triangular shaped h-BN domains on Ni(111). This work provides a promising approach to prepare unidirectionally aligned h-BN domains in a large area, and thus it is possible to achieve wafer-scale single crystal h-BN by stitching th...