Synthesis of hexagonal boron nitride 2D layers using polymer derived ceramics route and derivatives

Abstract

Hexagonal boron nitride (h-BN) is nowadays an increasingly attractive material, especially for two-dimensional material applications, due to its intrisic properties. However, its properties are highly dependent on the used synthesis approach. The polymer derived ceramics (PDCs) route allows elaboration of h-BN with tailored textural and structural properties. Here, we demonstrate the interest of the PDCs pathway for the synthesis of h-BN. Growth of h-BN single crystals with crystal sizes of a few microns at relatively low temperature and atmospheric pressure is successfully achieved from borazine precursor using PDCs. The crystallization is improved by additivation of 5 wt% of Li3N to the pre-ceramic polymer. Furthermore, by coupling PDCs with gas pressure sintering, starting from the same pre-ceramic polymer and 25 wt% of Li3N, the crystal size is enlarged up to hundreds of microns. The fabricated single crystals of pure h-BN can then be exfoliated into h-BN nanosheets. Finally, by combining PDCs with atomic layer deposition, functional BN nano-/hetero-structures are successfully synthesized from highly structured sensitive templates, making this ALD process a promising alternative for fabricating functional BN nanostructures.