Plasmon‐Enhanced Photodetection in Ferroelectric‐Tunable Two‐Dimensional Phototransistor

Attributed to the low absorbance originated from atomic‐scale thickness, photogating‐induced trapping effect is always implemented on two‐dimensional (2D) phototransistors to improve photogain and photoelectric conversion efficiency, which inevitably leads to a compromise to response speed. In this work, a high‐performing phototransistor based on WS 2 channel, Al:HfO 2 ferroelectric layer, and Au nanoparticles (NPs) is meticulously proposed. Au NPs with tailored nanostructures induce localized surface plasmon resonance (LSPR) to improve light harvesting. The synergistic interplay between plasmonic excitation effect and ferroelectric‐gating enables precise localized field engineering, which enhances exciton dissociation and mitigates competing trapping mechanisms. This strategy effectively promotes photocarrier multiplication and facilitates tunable charge transport. As a result, the proposed device demonstrates a prominent detectivity of 1.36 × 10 14 Jones along with a fast response speed of 9.51 ms at zero gate bias, achieving an appealing balance between detection efficiency and response time. Furthermore, the leakage current and heat loss are remarkably suppressed due to the gate‐free operation mode. The as‐developed phototransistor based on the dual mechanisms demonstrates a promising potential to obtain ultrasensitive large‐scale sensor arrays beyond the traditional photogating strategies.