Research progress on the epitaxial growth of hexagonal boron nitride on different substrates by the CVD method.

Hexagonal boron nitride (h-BN) has a hexagonal structure similar to graphene, comprising alternating boron and nitrogen atoms. This unique structure endows h-BN with a plethora of excellent properties, including a low dielectric constant, elevated thermal and chemical stability, substantial mechanical rigidity, and an exceptionally low friction coefficient, rendering it versatile across a spectrum of applications ranging from semiconductors to aerospace. Moreover, its smooth surface, absence of dangling bonds, and wide band gap make h-BN an optimal substrate and gate dielectric material for two-dimensional electronic devices. This article details the synthesis methodologies and research progress of h-BN epitaxial growth on solid transition metal, liquid metal, alloy, sapphire/metal and semiconductor substrates. In particular, progress in improving the quality and functionality of h-BN films by adapting processes and substrates has been rigorously reviewed. Finally, the characteristics of different substrates are summarized and the challenges faced by h-BN in future applications are discussed.