title: Gate-bias stress-dependent photoconductive characteristics of multi-layer MoS2 field-effect transistors.
abstract: We investigated the photoconductive characteristics of molybdenum disulfide (MoS2) field-effect transistors (FETs) that were fabricated with mechanically exfoliated multi-layer MoS2 flakes. Upon exposure to UV light, we observed an increase in the MoS2 FET current because of electron-hole pair generation. The MoS2 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 MoS2 surface. This photocurrent decay phenomenon of the MoS2 FET was influenced by the measurement environment (i.e., vacuum or oxygen environment) and the electrical gate-bias stress conditions (positive or negative gate biases). The results of this study will enhance the understanding of the influence of environmental and measurement conditions on the optical and electrical properties of MoS2 FETs.
authors.affiliation: Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 151-747, Korea.
authors.forename: Kyungjune
authors.initials: K
authors.lastname: Cho
authors.forename: Tae-Young
authors.initials: TY
authors.lastname: Kim
authors.forename: Woanseo
authors.initials: W
authors.lastname: Park
authors.forename: Juhun
authors.initials: J
authors.lastname: Park
authors.forename: Dongku
authors.initials: D
authors.lastname: Kim
authors.forename: Jingon
authors.initials: J
authors.lastname: Jang
authors.forename: Hyunhak
authors.initials: H
authors.lastname: Jeong
authors.forename: Seunghun
authors.initials: S
authors.lastname: Hong
authors.forename: Takhee
authors.initials: T
authors.lastname: Lee