Growth of centimeter-scale multilayer hexagonal boron nitride films using metal-boride-vapor CVD.

Multilayer hexagonal boron nitride (h-BN) films with atomically smooth surfaces and optically addressable spin defects are highly attractive for nanoelectronics, quantum sensors, and quantum memories. However, the controllable synthesis of multilayer h-BN remains a significant challenge. Here, we demonstrate the growth of centimeter-scale (∼1.5 cm × 1.5 cm), multilayer h-BN films (∼20-80 nm) on FeNi substrates using metal boride vapor and nitrogen gas as precursors. The films exhibit clear hexagonal lattice structures under atomic-resolution TEM, a sharp Raman E2g vibration mode (FWHM ∼ 11.18 cm-1), and a wide bandgap of ∼5.92 eV. We further reveal that the FeNi (111) facet adversely affects film continuity, offering guidance for substrate selection. This method presents a novel route for the growth of large-area, high-quality multilayer h-BN films and contributes to substrate screening for h-BN growth. These advances pave the way for future applications of h-BN in van der Waals electronic devices and quantum information technologies.