Transport Properties of Hydrogen-Terminated Silicon Surface Controlled by Ionic-Liquid Gating

We fabricated electric double-layer transistors on the hydrogen-terminated (111)-oriented surface of non-doped silicon using ionic liquid as a gate dielectric. We introduced hole carriers into silicon with the application of a negative gate voltage. The sheet resistance of silicon was controlled by more than three orders of magnitude at 220K by changing the gate voltage. The temperature dependence of sheet resistance became weak as the gate voltage was increased, suggesting the approach to an insulator-metal transition.