Thickness-Controlled Synthesis of Uniform Hexagonal Boron Nitride Films on Metal Alloys by Chemical Vapor Deposition

Two-dimensional (2D) multilayer hexagonal boron nitride (hBN) is a superior substrate for other 2D materials due to its insulating property, atomic-scale smoothness, and absence of dangling bonds, enhancing electrical or optical properties in high-performance 2D material-based devices. In most fabrication processes for 2D heterostructure devices, thick hBN flakes exfoliated from bulk have been used because of their high quality and simplicity in the process. However, exfoliated hBN flakes are limited in size and thickness control, impeding scale-up production for industrialization. Therefore, new synthesis strategies are required to overcome the drawback of the exfoliation method. In this work, we investigated the synthesis of large-area, multilayer hBN via atmospheric pressure chemical vapor deposition using single crystalline metal and single crystal alloy substrates. The synthesized results are characterized by optical microscopy, scanning electron microscopy, Raman spectroscopy, atomic force microscopy, etc. These studies provide a more comprehensive understanding of the growth mechanism of hexagonal boron nitride.