Self-Powered Photodetection in WSe2/CrOCl van der Waals Heterostructure

The 2-D transition metal dichalcogenides (TMDs) have emerged as promising materials for next-generation optoelectronic devices. Nevertheless, their application in self-powered photodetectors remains challenging, as device performance is often constrained by high dark currents and inefficient charge separation at zero bias. In this work, we demonstrate a self-powered photodetector based on a tungsten diselenide on chromium oxychloride (WSe2/CrOCl) van der Waals heterostructure with Schottky contacts. Electrical and optoelectronic characterizations reveal that the chromium oxychloride (CrOCl) substrate acts not only as a high-quality dielectric that drastically suppresses the dark current, but also as an active channel modulator. Leveraging its exceptionally high work function, CrOCl induces a massive interfacial charge transfer that p-dopes the WSe2 layer. Under illumination, this synergistic interlayer coupling overcomes contact barrier restrictions, amplifying the local built-in electric field at the Schottky junction and maximizing the spontaneous extraction of photogenerated carriers. Overall, this work demonstrates that integrating WSe2 with CrOCl provides a highly effective strategy to significantly enhance the performance of self-powered photodetectors.