Electrochemical manipulation of two-dimensional materials

The electronic properties of a variety of two-dimensional (2D) materials can be modulated by electrochemical modifications on mesoscopic scale. Here we demonstrate a proof-of-concept ionic field-effect transistor (iFET), which is based on reversible modifications of the electronic properties of a wide range of layered materials (e.g. 1T-TaS$_2$ and 2H-TaS$_2$) through gate-controlled electrochemical reactions with mobile ions in the electrolyte. By fine-tuning the electrochemical reactions, we can switch between Mott phase, superconducting phase, metallic phase and insulating phase in a single 1T-TaS$_2$ iFET device. Such technique opens up new possibilities in searching for the novel state of matter in 2D materials.