Growth of Large Single-Crystalline Monolayer Hexagonal Boron Nitride by Oxide-Assisted Chemical Vapor Deposition

We show how an oxide passivating layer on the Cu surface before the growth of h-BN by chemical vapor deposition (CVD) can lead to increased domain sizes from 1 to 20 μm by reducing the nucleation density from 106 to 103 mm–2. The h-BN domains within each Cu grain are well-oriented, indicating an epitaxial relationship between the h-BN crystals and the Cu growth substrates that leads to larger crystal domains within the film of ∼100 μm. Continuous films are grown and show a high degree of monolayer uniformity. This CVD approach removes the need for low pressures, electrochemical polishing, and expensive substrates for large-area continuous films of h-BN monolayers, which is beneficial for industrial applications that require scalable synthesis.