Negative Photoconductivity in 2D α-MoO₃/Ir Self-Powered Photodetector: Impact of Post-Annealing

Surface plasmon technology is regarded as having significant potential for the enhancement of the performance of 2D oxide semiconductors, especially in terms of improving the light absorption of 2D MoO₃ photodetectors. An ultrathin MoO₃/Ir/SiO₂/Si heterojunction Schottky self-powered photodetector is introduced here to showcase positive photoconductivity. In wafer-scale production, the initial un-annealed Mo/2 nm Ir/SiO₂/Si sample displays a sheet carrier concentration of 5.76 × 10¹¹/cm², which subsequently increases to 6.74 × 10¹²/cm² after annealing treatment, showing a negative photoconductivity behavior at a 0 V bias voltage. This suggests that annealing enhances the diffusion of Ir into the MoO₃ layer, resulting in an increased phonon scattering probability and, consequently, an extension of the negative photoconductivity behavior. This underscores the significance of negative photoconductive devices in the realm of optoelectronic applications.