Effects of the Substrate Structure on the CVD Growth of Two-Dimensional Hexagonal Boron Nitride

Due to its outstanding stability, flat surface, and wide band gap, two-dimensional hexagonal boron nitride (h-BN) has appeared as a vital element in a range of applications, including a perfect substrate for graphene devices, tunneling barriers, and deep-ultraviolet emitters. However, large-scale growth of high-grade h-BN using chemical vapor deposition (CVD) still remains challenging due to its dependence on a variety of parameters such as substrate structures, temperature, and precursor deposition rates. Here, we explore the atomic scale elementary nucleation and growth process of monolayer h-BN on normal, vacancy-disordered, and rough (terrace and step structure) Ni(111) surfaces using reactive force field molecular dynamics simulations. The impact of the precursor deposition rate and temperature on different Ni(111) substrates was also investigated. At 1500 K, a low precursor deposition rate favors large single-domain h-BN development on normal and vacancy-disordered Ni(111) substrates, whereas a higher deposition rate yields a single domain on a rough substrate. It is also explored that the initial growth rate of h-BN is higher on the rough substrate and lower on the vacancy-disordered substrate for single-domain h-BN growth. The formation of continuous h-BN islands is greater on a normal Ni substrate than the other two substrates. Although a small vacancy concentration (1.25%) in the Ni(111) substrate shows a minor effect on the growth of the h-BN layer, the rough surface shows a considerable effect on the h-BN growth. These findings pave the way for scalable high-quality CVD growth of h-BN, taking this promising material one step closer to practical applications.