Nucleation Control for Large, Single Crystalline Domains of Mono layer Hexagonal Boron Nitride via Si-Doped Fe Catalysts

The scalable chemical vapor deposition of monolayer hexagonal boron nitride (h-BN) single crystals, with lateral dimensions of similar to 0.3 mm, and of continuous h-BN monolayer films With large domain sizes (>25 mu m) is demonstrated via an admixture of Si to Fe catalyst films. A simple thin-filth Fe/'SiO2/Si catalyst system is used to show that controlled Si diffusion into the Fe catalyst allows exclusive nucleation of monolayer h-BN with very low nucleation densities upon exposure to undiluted borazine. Our systematic in situ and ex situ characterization of this catalyst system establishes, a basis for further rational catalyst design for compound 2D materials.