Controlled Ion Transport in Metal Halide Perovskites for Field-Effect Transistors Working at Room-Temperature

In metal halide perovskites, ion transport (or migration) under an electric field has been a serious issue for realizing stable and efficient semiconductor devices. The mobile ions significantly hamper electronic operation in such devices, for instance, field-effect transistors, mainly due to screening of an electric field, leading to unsuccessful gate modulation of a perovskite channel. Herein, we present a simple but effective method to control the movement of ions in the perovskites through an auxillary ferroelectric gate. A non-volatile electric field provided by the ferroelectric gate insulator successfully manipulates the mobile ions and thereby, electronic conduction in the perovskite channel is modulated at room-temperature. We make use of transistor device physics to uncover temperature-dependent semiconducting properties of a representative metal halide perovskite of cesium lead tribromide. Our method to control the ion transport allows us to take advantage of notorious ionic behaviors in the perovskites as an emerging electronic device of neuromorphic artificial synatic transistors. Our strategy can be potentially utilized to control mobile ions in various perovskite-based device platforms.