The effect of electron-beam irradiation (EBI) on MoS 2 -based photodetectors with various electrode structures was investigated to improve the electrical and photoelectrical properties. The MoS 2 fi lms were deposited at room temperature by RF magnetron sputtering and subsequently transformed into a two-dimensional layered structure by EBI treatment with the electron energy of 3 kV for 1 min. The electrical resistance and photoelectrical properties, such as photocurrent and photoresponsivity, of MoS 2 fi lms were examined with patterned Au/Ti electrodes as a top contact (TC) and a bottom contact structure. In addition, the interfacial eff ect of high-k dielectric materials of thin HfO 2 fi lm between MoS 2 and the SiO 2 /Si substrate was investigated to enhance the photoelectrical property. The MoS 2 photodetectors fabricated by the EBI before TC formation on HfO 2 exhibited the highest photoresponsivity of 11.88 mA/W, which was an increase of 6500% from the EBI before TC structure on SiO 2 . We believe that this work contributes to the improvement of contact and interface properties of MoS 2 -based photodetectors readily and quickly compared with conventional high-temperature thermal treatment.