Ionic Liquid Gated Vanadium Oxide Three Terminal Devices: Chemical Stability and Field Effect*

Understanding electrostatic field effect in correlated oxides is one approach to uncovering mechanisms leading to metal-insulator transition and further is of great interest in oxide-based device technologies. We have fabricated ionic liquid gated VO$_{2}$ three-terminal devices. The VO$_{2}$/IL interface properties were systematically studied with emphasis on electrochemical stability, gate capacitance and charging/discharging using photoelectron spectroscopy, impedance spectroscopy and other electrical characterization. We have observed a large modulation of VO$_{2}$ channel conductance at room temperature with polarity dependence. Interestingly, the conductance modulation also exhibits a time-dependent response to external gate bias and possible mechanisms will be discussed.