Direct growth Bi2O₂Se nanosheets on SiO₂/Si substrate for high-performance and broadband photodetector

Bi₂O₂Se, a newly emerging two-dimensional (2D) material, has attracted significant attention as a promising candidate for optoelectronics applications due to its exceptional air stability and high mobility. Generally, mica and SrTiO₃substrates with lattice matching are commonly used for the growth of high-quality 2D Bi₂O₂Se. Although 2D Bi₂O₂Se grown on these insulating substrates can be transferred onto Si substrate to ensure compatibility with silicon-based semiconductor processes, this inevitably introduces defects and surface states that significantly compromise the performance of optoelectronic devices. Herein we employ Bi₂Se₃as the evaporation source and oxygen reaction to directly grow Bi₂O₂Se nanosheets on Si substrate through a conventional chemical vapor deposition method. The photodetector based on the Bi₂O₂Se nanosheets on Si substrate demonstrates outstanding optoelectronics performance with a responsivity of 379 A W^-1, detectivity of 2.9 × 10¹⁰Jones, and rapid response time of 0.28 ms, respectively, with 532 nm illumination. Moreover, it also exhibits a broadband photodetection capability across the visible to near-infrared range (532-1300 nm). These results suggest that the promising potential of Bi₂O₂Se nanosheets for high-performance and broadband photodetector applications.