▎ 摘　　要

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 cm(2) V-1 s(-1)-when graphene is encapsulated with another hBN sheet. Multilayers of hexagonal boron nitride can be grown using a chemical vapour deposition process on iron-nickel foil and integrated into a large array of graphene devices that exhibit room-temperature carrier mobilities of up to around 10,000 cm(2) V-1 s(-1).