Crystallization Engineering of GaAs/Sb ₂ S ₃ Core‐Shell Nanowires for Gain Manipulation of Photodetectors

ABSTRACT Photodetectors, based on GaAs nanowires (NWs), hold significant promise in the fields of high integration micro‐ and nano‐optoelectronics applications because of their outstanding electronic and optical properties. To date, significant efforts have been directed toward enhancing the performance of photodetectors, aiming for high detectivity and fast response. However, considerable challenges remain in achieving both efficient separation of carriers and enhancing gain capabilities simultaneously. In this work, we report a high‐performance GaAs core–shell nanowire photodetector featuring a hybrid‐crystallization (HC) Sb 2 S 3 shell that incorporates homogeneous crystalline quantum dots (QDs) within an amorphous matrix. The Sb 2 S 3 shell reconfigures the valence valley and introduces trap states, thereby effectively separating photo‐generated carriers spatially while serving as a conduit for minority carriers. The unique hybrid‐crystallization shell emerges as a crucial factor in enhancing performance. The core–shell nanowire photodetector presents a high responsivity of 1061.3 A W −1 , a detectivity of 1.2 × 10 12 cm Hz 0.5 W −1 , and an external quantum efficiency (EQE) of 1.63 × 10 5 % at 5 V under 808 nm irradiation, surpassing those of conventional GaAs nanowire photodetectors. Moreover, this device demonstrates rapid response characteristics. These findings underscore a unique strategy for designing high‐performance nanowire photodetectors through the incorporation of engineered amorphous quantum dots.