Chemical potential imbalance mediated CVD growth of atomically thin hexagonal boron nitride fractal patterns

• The fractal controllable growth of monolayer hexagonal boron nitride by CVD. • Fractal patterns are generated in a severe N/B chemical potential imbalance. • Chemical potential influences the kinetic growth dynamics of edges. • Fractal dimension analysis reveals rough boundaries and self-similarity. Fractal patterns produced in non-equilibrium processes are ubiquitous in nature, but the mechanisms behind them are not fully understood. Here, we successfully fabricated nitrogen-rich edge monolayer hexagonal boron nitride (h-BN) fractal flakes using the relatively high N precursor flux through chemical vapor deposition. Fractal dimension analysis was introduced to characterize the boundary roughness of fractal flake, the fractal dimension calculated by the box-counting method is 1.92, suggesting that the h-BN fractal flake possesses a rough boundary. Moreover, a possible morphogenesis mechanism was proposed based on the crystal growth principle, elucidating the role of severe chemical potential imbalance in the formation of fractal flakes.