Photocurrent response of MoS₂ field-effect transistor by deep ultraviolet light in atmospheric and N₂ gas environments.

Molybdenum disulfide (MoS2), which is one of the representative transition metal dichalcogenides, can be made as an atomically thin layer while preserving its semiconducting characteristics. We fabricated single-, bi-, and multilayer MoS2 field-effect transistor (FET) by the mechanical exfoliation method and studied the effect of deep ultraviolet (DUV) light illumination. The thickness of the MoS2 layers was determined using an optical microscope and further confirmed by Raman spectroscopy and atomic force microscopy. The MoS2 FETs with different number of layers were assessed for DUV-sensitive performances in various environments. The photocurrent response to DUV light becomes larger with increasing numbers of MoS2 layers and is significantly enhanced in N2 gas environment compared with that in atmospheric environment.