High performance self-powered photodetector based on van der Waals heterojunction.

Self-powered photodetectors that do not require external power support are expected to play a key role in future photodetectors due to their low power characteristics, but achieving high responsivity remains a challenge. 2D van der Waals heterojunctions are a promising technology for high-performance self-powered photodetectors due to their excellent optical and electrical properties. Here, we fabricate a self-powered photodetector based on InSe/WSe/ReSvan der Waals heterojunction self-powered photodetector. Due to the presence of ReSlayer, photocurrent is enhanced as a result of the increase in light absorption efficiency and the effective region for generating photogenerated carriers. The built-in electric field is enhanced by a negative 'back-gate voltage' along the p-n junction vertical direction generated by the electrons in the photo-generated electrons accumulation layer. Accordingly, the optical responsivity and the photoresponse speed of this heterojunction self-powered photodetector are greatly boosted. The proposed self-powered photodetector based on the InSe/WSe/ReSheterojunction exhibits a high responsivity of 438 mA W, which is 17 times higher compared to the InSe/WSephotodetector, a self-powered current (1.1 nA) that is an order of magnitude higher than that of the InSe/WSephotodetector, and a fast response time that is 250% faster. Thus the self-powered photodetector with a stronger built-in electric field and a wider depletion zone can provide a new technological support for the fabrication of high responsivity, low power consumption and high speed self-powered photodetectors based on van der Waals heterojunctions.