Electric-Field-Induced Insulator to Metal Transition in α-MoO₃

Layered α-MoO₃ is well known for its intriguing optical and electrical properties based on two dimensional (2D) character. Here we show the reversible metallization and pronounced structural changes of MoO₃ thin film by electrolyte gating. The resistivity of the gated thin film is tuned by five orders of magnitude at room temperature and a clear insulator-to-metal phase transition is observed accompanied by the change in out-of-plane lattice constant.