Controllable growth of triangular hexagonal boron nitride domains on copper foils by an improved low-pressure chemical vapor deposition method.

We demonstrate an improved low-pressure chemical vapor deposition method to fabricate hexagonal boron nitride (h-BN) domains of a few layers (one-four layers) from ammonia borane by adding a small quartz tube to stabilize the gas flow over the copper substrate and reducing the growing rate of h-BN. The h-BN grows freely and spontaneously to form triangular domains on the Cu (100) plane. The triangular domains are prone to be parallel to each other on the copper substrate. The h-BN domains grow by extending in the normal direction of the triangle and form a large thin film by joining together. Both the size and coverage rate on Cu foils are well controlled by tuning the amount of ammonia borane.