Defect engineering via O-Se co-treatment enabled high-performance self-powered Au/O-Se MoS2/In photodetector

Abstract

Self-powered photodetectors (SPPDs) are essential for energy-self-sufficient optical imaging and optical communication applications. However, the defects generated in two-dimensional transition metal dichalcogenides lead to Fermi-level pinning at metal–semiconductor interfaces and non-radiative recombination of carriers, thereby seriously degrading the performance of SPPDs. The traditional defect engineering predominantly relies on single-atom passivation strategies, which essentially target a single type of defect, making it difficult to suppress multiple defect states located at different energy levels. Herein, we demonstrate a sequential multi-atom cooperative defect repair strategy in MoS2, which simultaneously repairs multiple defect states associated with sulfur vacancies within a single material. As a result, the Au/O-Se MoS2/In photodetector exhibits a high responsivity of 0.21 A/W, together with an ultrafast response speed of 720 ns under zero bias voltage. The device achieves high-fidelity optical imaging and reliable optical communication under self-powered operation. This work establishes a universal strategy for defect control through multi-atom cooperative effects, providing an avenue for achieving high photoelectric conversion in next-generation optoelectronic devices.