Growth and etching of monolayer hexagonal boron nitride

The full spectrum from attachment-kinetic-dominated to diffusion-controlled modes is revealed for the cases of monolayer h-BN chemical vapor deposition (CVD) growth and Ar/H₂ etching. The sets of grown and etched structures exhibit well-defined shape evolution from Euclidian to fractal geometry. The detailed abnormal processes for merging h-BN flakes into continuous structures or film are first observed and explained.