Toward growth of wafer-scale single-crystal hexagonal boron nitride sheets

Abstract

Hexagonal boron nitride (hBN) has a two-dimensional planar structure without dangling bonds and is considered an insulator material that can overcome the limitations of SiO2 and HfO2, which typically exhibit large densities of dangling bonds and charged impurities at the interface. However, most of the reported hBN films prepared by chemical vapor deposition (CVD) are polycrystalline with grain boundaries. The grain boundaries of a polycrystalline hBN cause current leakage and gas permeability. A recent notable study reports the growth of wafer-scale single-crystal hBN monolayer, which could mitigate the aforementioned problems caused by polycrystalline hBN films. In this perspective, we discuss the recent progress in the research on single-crystal hBN and the direction to be taken for single-crystal hBN in future. The progress is closely related to the development of a single-crystal substrate and large area of monolayer single-crystal was grown on Cu (111). In terms of the hBN growth, the next step would be to grow multilayer single-crystal hBN, which is expected to expand the scope of applications.