Single-Layer MoS2 Phototransistors

A new phototransistor based on the mechanically-exfoliated single-layer MoS2 nanosheet is fabricated and its light-induced electric properties are investigated in details. Photocurrent generated from the phototransistor is solely determined by the illuminated optical power at a constant drain or gate voltage. The switching behavior of photocurrent generation and annihilation can be completely finished within ca. 50 ms and it shows good stability. Especially, the single-layer MoS2 phototransistor exhibits a better photoresponsivity as compared with the graphene-based device. The unique characteristics of incident-light control, prompt photoswitching and good photoresponsivity from the MoS2 phototransistor pave an avenue to develop the single-layer semiconducting materials for multi-functional optoelectronic device applications in future.