Rotational epitaxy of h-BN on Cu (110)

Abstract

The growth of wafer-scale, single-crystalline hexagonal boron nitride (h-BN) monolayers on catalytic metallic substrates, requires a sparse nucleation density. At high temperatures (>1000 ∘C), preparation of vicinal Cu (110) with H2 annealing is reported to provide preferential nucleation of single antiphase domains of h-BN with facets parallel to Cu steps. We have used in situ low-energy electron microscopy (LEEM) to image nucleation and growth of h-BN islands on a Cu (110) single crystal at lower temperatures (650–750)∘C. With H2 annealing, diffraction (LEED) and dark field imaging (LEEM) confirmed the formation of three sets of h-BN antiphase domains. Two sets are epitaxially aligned with four Cu 〈11〉 in-plane directions, the lowest lattice mismatch available. While alignment is excellent in one direction, the other trigonal directions are 10.4∘ rotationally mismatched. A third pair of antiphase domains nucleates aligned with 〈10〉 in-plane directions. These domains are midway, rotated 5.2∘ with respect to either type of {111} domain, and have the lowest interfacial energy. Localized defects were found to correlate with every island nucleation event.