Development of Self-Powered MoS 2-x -Based Photodetector with Different Contact Structures

This research focuses on analyzing the effect of the asymmetric contact structure on the photodetector properties. The photocurrent of 118.79 μA is achieved for the device with an asymmetric electrode (Au/MoS 2-x /Ag@forward) configuration. However, when it comes to self-powered devices, in the symmetric electrode configuration, the electric field is generated in the same direction at the metal–semiconductor region. This hinders the flow of electrons under zero-bias conditions. Meanwhile, the asymmetric electrode configuration forms an energy gradient in the semiconductor’s conduction band. This gradient allows electrons to flow toward the lower potential barrier between the metal–semiconductor junctions even without bias conditions. Therefore, the Au/MoS 2-x /Ag device shows a photocurrent of 0.017 and 0.066 μA even under zero bias conditions under the illumination of ultraviolet and visible lights, respectively.