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.