A study on ionic gated MoS2 phototransistors

Molybdenum disulfide (MoS2) holds great promise in the future applications of nanoelectronics and optoelectronic devices. Exploring those interesting physical properties of MoS2 using a strong electric field provided by electrolyte-gel is a robust approach. Here, we fabricate an MoS2 phototransistor gated by electrolyte-gel which is located on a fused silica substrate. Under the modulation of electrolyte-gel, the Schottky barrier between MoS2 and source/drain electrodes can be widely regulated from 11 to 179 meV. The MoS2 phototransistor exhibits excellent responsivity of 2.68 × 104 A/W and detectivity of 9.6 × 1010 Jones under visible incident light at negative gate voltage modulation. We attribute the optoelectronic performance enhancement to the Schottky barrier modulation of electrolyte-gel gating. It makes the device suitable for applications in high-sensitive photodetectors.