Mechanism of Controllable Growth of Large-Area Single-Crystal Hexagonal Boron Nitride on Preoxidized Copper Substrate.

Two-dimensional (2D) hexagonal boron nitride (-BN) exhibits promising properties for electronic and photoelectric devices, while the growth of high-quality -BN remains challenging. Here we theoretically explored the mechanism of epitaxial growth of high-quality -BN by using the preoxidized and hydrogen-annealed copper substrate, i.e., CuO. It is revealed thermodynamically that the unidirectional nucleation of -BN can be rationalized on the symmetry-matched CuO(111) surface rather than the antiparallel nucleation on the Cu(111) surface. Kinetically, the dehydrogenation of feedstock of -BN on the CuO(111) surface is also much easier than that on the Cu(111) surface. Both the B and N atoms are energetically more preferred to stay on the surface rather than inside the body of CuO, which leads to a surface-diffusion-based growth behavior on the CuO(111) surface instead of the precipitation-diffusion mixed case on the Cu(111) surface. Our work may guide future experimental design for the controllable growth of wafer-scale single-crystal -BN.