Synthesis of hexagonal boron nitride: From bulk crystals to atomically thin films

Hexagonal boron nitride (h-BN) is a wide band gap layered material that is promising for a plethora of applications ranging from neutron detection to quantum information processing. Moreover, it has become highly relevant in the field of two-dimensional crystals and their van der Waals heterostructures due to its multiple functionality as substrate, encapsulation layer, tunneling barrier, or dielectric layer in various device schemes. Hence, controlled synthesis of h-BN has been intensively pursued aiming at its future implementation into different technologies. Herein, recent progress in growth of h-BN, either as bulk crystals or large-area thin films with thicknesses varying from tens of micrometers down to a single atomic layer, is reviewed. A general description of the main methods utilized including their technical aspects is presented in conjunction with the discussion of the material properties determined using well-established characterization tools. Also the main challenges and application prospects of each growth approach are addressed.