High-Speed Self-Powered Photodetector Based on PdPS/MoS₂ van der Waals Heterostructure

AbstractWe report a high-speed self-powered photodetector based on a PdPS/MoS₂ van der Waals (vdW) heterostructure, in which an experimentally verified built-in electric field enables efficient photovoltaic operation without external bias. The Type-II band alignment at the PdPS/MoS₂ interface after contact generates a built-in potential of 251.72 meV, as directly measured by scanning Kelvin probe microscopy, leading to effective charge separation and rapid carrier transport. Under 635 nm illumination, the device exhibits peak responsivity of 11 mAW–1. Notably, the photodetector achieves a 3 dB bandwidth of 6 kHz with fast rise and decay times of 52.5 μs and 54.5 μs at 3 dB bandwidth, respectively, placing it among the fastest self-powered 2D vdW heterostructure photodetectors reported to date. The strong internal electric field suppresses carrier recombination and eliminates the need for external bias, enabling energy-efficient and high-speed operation. These results demonstrate that PdPS/MoS₂ vdW heterostructures provide an effective platform for next-generation self-powered optoelectronic devices requiring fast response and low power consumption.