Chemical Potential-Manipulated Growth of Large-Area High-Quality 2D Boron Nitride Films by APCVD

The two-dimensional material, hexagonal boron nitride (h-BN), has received significant interest due to its fascinating optical and electrical properties. However, the conventional chemical vapor deposition (CVD) process for growing h-BN often results in undesirable grain boundaries and defects due to its high nucleation density. To overcome this limitation, we studied the initial growth procedure for monomer formation, adsorption, and reaction on a Cu surface. The calculation results indicated that manipulating the growth conditions can effectively control the formation of the preferential building blocks of h-BN, such as the B/N atom, BN/BN2/B2N molecules, and BN3/B3N clusters, subsequently resulting in different nucleation dynamics and growth modes. Especially, a N-rich atmosphere could significantly suppress the h-BN nucleation due to the higher formation energy of the preferential building blocks on the Cu surface. Further experimental work verified this manipulation strategy well by constructing N-rich and B-rich growth conditions, which resulted in large-scale and high-quality h-BN films with few defects and almost unresolvable grain boundaries. The results demonstrate that the chemical-potential-based manipulation strategy has promise for optimizing h-BN growth dynamics and improving its practical applications.