Transistors with chemically synthesized layered semiconductor WS₂ exhibiting 10⁵ room temperature modulation and ambipolar behavior

We report the realization of field-effect transistors (FETs) made with chemically synthesized multilayer crystal semiconductor WS₂. The Schottky-barrier FETs demonstrate ambipolar behavior and a high (∼10⁵×) on/off current ratio at room temperature with current saturation. The behavior is attributed to the presence of an energy bandgap in the ultrathin layered semiconductor crystal material. The FETs also show clear photo response to visible light. The promising electronic and optical characteristics of the devices combined with the chemical synthesis, and flexibility of layered semiconductor crystals such as WS₂ make them attractive for future electronic and optical devices.