Multilayer hexagonal boron nitride (hBN) can be used to preserve the intrinsic physical properties of other two-dimensional materials in device structures. However, integrating the material into large-scale two-dimensional heterostructures remains challenging due to the difficulties in synthesizing high-quality large-area multilayer hBN and combining it with other two-dimensional material layers of the same scale. Here we show that centimetre-scale multilayer hBN can be synthesized on iron–nickel alloy foil by chemical vapour deposition, and then used as a substrate and as a surface-protecting layer in graphene field-effect transistors. We also develop an integrated electrochemical transfer and thermal treatment method that allows us to create high-performance graphene/hBN heterostacks. Arrays of graphene field-effect transistors fabricated by conventional and scalable methods show an enhancement in room-temperature carrier mobility when hBN is used as an insulating substrate, and a further increase—up to a value of 10,000 cm² V⁻¹ s⁻¹—when graphene is encapsulated with another hBN sheet.

多层六方氮化硼 (hBN) 可用于保留器件结构中其他二维材料的固有物理特性。然而，由于难以合成高质量的大面积多层 hBN 并将其与其他相同尺寸的二维材料层结合，因此将该材料集成到大规模二维异质结构中仍然具有挑战性。在这里，我们表明可以通过化学气相沉积在铁镍合金箔上合成厘米级多层 hBN，然后用作石墨烯场效应晶体管的衬底和表面保护层。我们还开发了一种集成的电化学转移和热处理方法，使我们能够创建高性能石墨烯/hBN 异质堆。²  V ⁻¹  s ⁻¹ —当石墨烯被另一个hBN片包封时。