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.

六方氮化硼 (h-BN) 是一种二维 (2D) 材料，有望用作基于石墨烯的器件的支撑和钝化层。然而，传统的剥离技术难以获得大面积的h-BN。在这里，我们通过使用外延金属膜作为催化剂来生长具有大晶粒尺寸的少层 h-BN，进行化学气相沉积 (CVD)。发现获得的 h-BN 的晶粒尺寸为几微米或更大。此外，我们用导电原子力显微镜评估了几层 h-BN 的绝缘性能。假设平行板模型，击穿强度估计至少为 7.5-45.5 MV cm ^-1，考虑到 h-BN 厚度的变化。这些值与先前研究中剥离的 h-BN 获得的值相当。考虑到可扩展性和绝缘特性，我们外延合成的 h-BN 有望用于未来的石墨烯器件。