Homo‐type α‐In2Se3/PdSe2 Ferroelectric van der Waals Heterojunction Photodetectors with High‐performance and Broadband

Abstract Two‐dimensional (2D) materials have attracted extensive attention in the field of photodetection thanks to their unique physical properties. Among them, the PdSe 2 nanoflake shows great potential. However, the performance of the PdSe 2 ‐based photodetector with a hetero‐type heterojunction remains poor due to the severe tunneling‐assisted interfacial recombination of photogenerated electron‐hole pairs in the thin bilateral‐depletion heterojunctions. In this work, a novel photodetector with a α‐In 2 Se 3 /PdSe 2 homo‐type heterojunction for both high‐performance and broadband detection from visible to short‐wave infrared is constructed. The high‐performance of the photoresponsivity of 4.64 × 10 3 A·W −1 , the external quantum efficiency of 1.08 × 10 6 %, and the specific detectivity of 1.55 × 10 14 Jones at 532 nm is the result of the homo‐type unilateral‐depletion junction which can promote the effective separation of photogenerated electron‐hole pairs compared to the hetero‐type. Also, adjusting the α‐In 2 Se 3 ferroelectric polarization state further optimizes the unilateral depletion region. In addition, the photodetector can work in a self‐powered mode. This study suggests that the PdSe 2 ‐based homo‐type device has great application potential in the field of 2D optoelectronics.