Gate-bias stress-dependent photoconductive characteristics of multi-layer MoS 2 field-effect transistors

We investigated the photoconductive characteristics of molybdenum disulfide (MoS 2 ) field-effect transistors (FETs) that were fabricated with mechanically exfoliated multi-layer MoS 2 flakes. Upon exposure to UV light, we observed an increase in the MoS 2 FET current because of electron–hole pair generation. The MoS 2 FET current decayed after the UV light was turned off. The current decay processes were fitted using exponential functions with different decay characteristics. Specifically, a fast decay was used at the early stages immediately after turning off the light to account for the exciton relaxation, and a slow decay was used at later stages long after turning off the light due to charge trapping at the oxygen-related defect sites on the MoS 2 surface. This photocurrent decay phenomenon of the MoS 2 FET was influenced by the measurement environment (i.e., vacuum or oxygen environment) and the electrical gate-bias...

Kyungjune Cho, Tae-Young Kim, Woanseo Park, Juhun Park, Dongku Kim, Jingon Jang, Hyunhak Jeong, Seunghun Hong and Takhee Lee

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