Investigations of MoS₂-Based Self-Powered M–S–M Photodetectors with Low Defect Density and Fast Response and Low-Temperature Characteristics

In this study, a self-powered MoS 2 thin-film M–S–M (metal–semiconductor–metal) photodetector driven by Au/Ag asymmetric electrodes was demonstrated. In the previously reported work, the compatibility of photodiode structures and CMOS processes is not as favorable as the M–S–M photodetector. However, the M–S–M photodetector often requires biased operation. In this research, MoS 2 films with different layers were synthesized using a thermolysis method and sulfur powders were added during the process to lower the film defect density. We utilized metals with different work functions to fabricate an asymmetric bending of the energy bands at zero bias, achieving the self-powered operation. The fabricated thin-film photodetector device exhibited a responsivity of up to 75 mA/W in a zero-bias mode and an ultrafast rise/fall time of 8.85/0.96 ms. Furthermore, the photodetector proved its application potential by operating effectively at a low temperature of 225 K. This capability makes it highly promising for sensing applications in cold or polar regions.