Contact and Interface Engineering of MoS2-Based Photodetectors Using Electron-Beam Irradiation

Abstract

The effect of electron-beam irradiation (EBI) on MoS₂-based photodetectors with various electrode structures was investigated to improve the electrical and photoelectrical properties. The MoS₂ films 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 MoS₂ films were examined with patterned Au/Ti electrodes as a top contact (TC) and a bottom contact structure. In addition, the interfacial effect of high-k dielectric materials of thin HfO₂ film between MoS₂ and the SiO₂/Si substrate was investigated to enhance the photoelectrical property. The MoS₂ photodetectors fabricated by the EBI before TC formation on HfO₂ exhibited the highest photoresponsivity of 11.88 mA/W, which was an increase of 6500% from the EBI before TC structure on SiO₂. We believe that this work contributes to the improvement of contact and interface properties of MoS₂-based photodetectors readily and quickly compared with conventional high-temperature thermal treatment.