Optimization of NC‐LSPR coupled MoS ₂ phototransistors for high‐performance broad‐spectrum detection

Abstract In this work, negative‐capacitance (NC) and local surface plasmon resonance (LSPR) coupled MoS 2 phototransistors with a gate stack of HZO/AuNPs/Al 2 O 3 /MoS 2 are fabricated, and the impacts of Al 2 O 3 interlayer‐thickness ( T AlO ) on the LSPR effect, the tensile strain on MoS 2 from the Au nanoparticles (AuNPs), the capacitance matching of the NC effect from Hf 0.5 Zr 0.5 O 2 (HZO) ferroelectric layer and the optoelectrical properties of the relevant devices are investigated. Through optimizing T AlO , excellent optoelectrical properties of phototransistors with a T AlO of 3 nm are achieved: a subthreshold swing ( SS ) of 25.76 mV/dec and ultrahigh detectivity of over 10 14 Jones under 740 nm illumination. This is primarily because the NC‐LSPR coupled structure can achieve an ultra‐low SS through capacitance matching and a good interface passivation through optimizing Al 2 O 3 interlayer to maintain effective LSPR and strain effects cross the MoS 2 to enhance optical absorption and detection range. This work provides a comprehensive analysis on effective distance range of the non‐direct‐contacted LSPR effect and its combination with capacitance matching of NC effect, culminating in an optimized NC‐LSPR coupled MoS 2 phototransistor with a good consistency across an array of 30 devices, and offering a viable solution for the preparation of large‐area, high‐performance and broad‐spectrum response 2D phototransistor array.