Development of Self-Powered MoS2-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 mu A is achieved for the device with an asymmetric electrode (Au/MoS2-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/MoS2-x/Ag device shows a photocurrent of 0.017 and 0.066 mu A even under zero bias conditions under the illumination of ultraviolet and visible lights, respectively.