Molecular Beam Epitaxial Growth Of Hexagonal Boron Nitride On Ni Foils

Hexagonal boron nitride (h-BN) was synthesized by molecular beam epitaxy on polycrystalline Ni foils using borazine (B3N3H6) as precursor. Our photoemission analysis shows that several components of boron and nitrogen are detected, suggesting the complex nature of the bonds noticeably at the h-BN/Ni interface. The BN thickness was estimated by photoemission and the BN distribution by time-of-flight secondary ion mass spectroscopy. Due to the catalytic effect of the Ni substrate, this thickness is self-limited in the range 1-2 layers regardless of the borazine dose. A spatially resolved photoemission study was carried out before and after transfer of the h-BN on a Si substrate. It shows that a strong electronic coupling exists at the interface between h-BN and polycrystalline Ni, not only for (111) grains, which disappears after transfer on Si. In addition, we highlight the importance of detecting pi plasmons in the photoemission spectra to confirm the hexagonal nature of BN.