Few-layer hexagonal boron nitride synthesized by chemical vapor deposition and its insulating properties

Abstract

Hexagonal boron nitride (h-BN), which is one of two-dimensional (2D) materials, is expected to be used as supporting and passivation layers for graphene-based devices. However, it is difficult to obtain large-area h-BN by the conventional exfoliation techniques. Here, we performed chemical vapor deposition (CVD) by employing epitaxial metal films as a catalyst to grow few-layer h-BN with a large grain size. The grain sizes of h-BN obtained were found to be a few micrometers or larger. Furthermore, we evaluated insulating properties of few-layer h-BN with conductive atomic force microscopy. Assuming a parallel plate model, a breakdown strength was estimated to be at least 7.5-45.5 MV cm-1, considering variations in h-BN thickness. These values are comparable with that obtained for exfoliated h-BN in a previous study. Considering the scalability and insulating properties, our epitaxially-synthesized h-BN is expected to be used for future graphene devices.