Ultrahigh‐Response of WSe ₂ Homojunction Photodetectors Induced by Ferroelectric Domains in Periodically Poled Lithium Niobate

Abstract This paper proposes a high‐performance photodetector based on a ferroelectric‐modulated homojunction coupled by periodically poled lithium niobate (PPLN) and WSe ₂ . Through the synergistic effect of interface engineering and a periodic ferroelectric substrate, non‐volatile electrostatic doping of WSe ₂ is achieved, and a periodic homojunction with a built‐in electric field is constructed on the intrinsic material. This design overcomes the limitations of lattice mismatch and interfacial defects in traditional vertical heterojunctions, significantly enhancing carrier separation efficiency. Under 512 nm illumination, the device achieves an ultra‐high responsivity of 37.1 A W ⁻¹ , a specific detectivity of 2.46 × 10 ¹⁴ Jones, and a fast response time of 150 µs, with comprehensive performance surpassing most 2D material photodetectors. Its excellent performance stems from the synergistic effect of ferroelectric‐induced carrier modulation and the photovoltaic effect of the homojunction. The non‐volatile doping strategy provides a new scheme for large‐scale fabrication and environmental stability of devices, holding significant application potential in the fields of photoelectric sensing and imaging. This study provides a brand‐new approach for the high‐performance optimization of 2D material optoelectronic devices through ferroelectric domain engineering.