▎ 摘　　要

We demonstrate a considerable suppression of the low-field leakage through a Y2O3 topgate insulator on graphene by applying high-pressure O-2 at 100 atm during post-deposition annealing (HP-PDA). Consequently, the quantum capacitance measurement for the monolayer graphene reveals the largest Fermi energy modulation (E-F = similar to 0.52 eV, i.e., the carrier density of similar to 2 x 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. (C) 2014 AIP Publishing LLC.