Wafer-Scale Single-Crystal Monolayer Graphene Grown Directly on Insulating Substrates

Abstract

Currently, the direct synthesis of inch-scale single-crystal graphene on insulating substrates is limited by the lack of metal catalysis, suitable crystallization conditions, and self-limiting growth mechanisms. In this study, we investigated a direct growth of adlayer-free ultra-flat wafer-scale single-crystal monolayer graphene on insulating substrates by the multi-loop plasma-etching-assisted chemical vapor deposition (MPE-CVD) method. Firstly, an atomic-thick growth nanochamber was created by fabricating single-crystal Cu(111) foils on Al2O3(0001) substrates, in which graphene was directly synthesized by MPE-CVD. After growth, the Cu(111) foil was detached using a liquid-nitrogen-assisted separation method, and the ultra-high-quality single-crystal graphene film was experimentally achieved on Al2O3(0001). The field-effect transistors fabricated on the directly grown graphene exhibited excellent electronic transport properties with high carrier mobilities. This work breaks the bottleneck in the direct synthesis of single-crystal graphene on insulating substrates and paves the way for next-generation carbon-based atomic electronics and semiconductor nanodevices.