Enhanced Performance of an Au/MoS2/GaAs Photodetector by Room-Temperature Metal Electrode Transfer

Recently, self-powered MoS2/GaAs photodetectors have attracted intensive attention. However, thermal processing following metal–electrode deposition tends to damage the lattice structure of MoS2, leading to degraded device performance and poor consistency. In this work, Au/MoS2/GaAs photodetectors are fabricated using two different methods of transferring Au (Tr-Au) and thermal evaporation Au (TE-Au), and their photoelectric performances are compared. It is found that, compared to TE-Au devices, the Tr-Au devices exhibit higher responsivity (45.29 A/W) and detectivity (3.11 × 1013 Jones). The underlying mechanisms are attributed to a significant reduction in defect traps in MoS2 and a smooth MoS2/GaAs heterojunction interface, which collectively increase photocurrent and suppress dark current. Therefore, the room-temperature Au transfer method shows great promise for the fabrication of high-performance optoelectronic devices.