Fabrication of transferable Al₂O₃ nanosheet by atomic layer deposition for graphene FET

Without introducing defects in the monolayer of carbon lattice, the deposition of high-κ dielectric material is a significant challenge because of the difficulty of high-quality oxide nucleation on graphene. Previous investigations of the deposition of high-κ dielectrics on graphene have often reported significant degradation of the electrical properties of graphene. In this study, we report a new way to integrate high-κ dielectrics with graphene by transferring a high-κ dielectric nanosheet onto graphene. Al₂O₃ film was deposited on a sacrificial layer using an atomic layer deposition process and the Al₂O₃ nanosheet was fabricated by removing the sacrificial layer. Top-gated graphene field-effect transistors were fabricated and characterized using the Al ₂O₃ nanosheet as a gate dielectric. The top-gated graphene was demonstrated to have a field-effect mobility up to 2200 cm²/(V s). This method provides a new method for high-performance graphene devices with broad potential impacts reaching from high-frequency high-speed circuits to flexible electronics.