High‐Performance Broadband Photodetector Based on PbI₂/Bi₂S₃/p‐Si Heterojunction

Herein, Bi 2 S 3 (BS) device is prepared using the sol–gel spin coating method, which is rarely employed in the field of Bi 2 S 3 photodetectors (PDs), and the PbI 2 /Bi 2 S 3 /p‐Si (PBSS) heterojunction is constructed for the first time. The PBSS PD device exhibits a ultraviolet–visible light–infrared (UV–Vis–IR) broadband response ranging from 365 to 1200 nm. Under a 5 V bias and 880 nm illumination, the switching ratio, responsivity, and detectivity of the PBSS heterojunction PD are 4.64 × 10 3 , 397.60 mA W −1 , and 5.67 × 10 11 Jones, which are higher than those of the single BS PD for 25, 7, and 13 times, respectively. Besides, the current decay time of PBSS is 22.5 ms, which is 157 times faster than that of BS PD. Furthermore, the energy band analysis reveals that the stepped band alignment of Bi 2 S 3 , PbI 2 , and p‐Si semiconductors plays a pivotal role in facilitating efficient carrier separation. These findings underscore that the obtained high‐performance PbI 2 /Bi 2 S 3 /p‐Si heterojunction PD shows a significant potential for applications in UV–Vis–IR broadband PD.