Large Fermi energy modulation in graphene transistors with high-pressure O₂-annealed Y₂O₃topgate insulators

We demonstrate a considerable suppression of the low-field leakage through a Y2O3 topgate insulator on graphene by applying high-pressure O2 at 100 atm during post-deposition annealing (HP-PDA). Consequently, the quantum capacitance measurement for the monolayer graphene reveals the largest Fermi energy modulation (EF = ~0.52 eV, i.e., the carrier density of ~2*10^13 cm^-2) in the solid-state topgate insulators reported so far. HP-PDA is the robust method to improve the electrical quality of high-k insulators on graphene.