Bi₂O₂Se nanoplates for broadband photodetector and full-color imaging applications

Broadband light detection and sensing are widely applied in modern technology. As a promising candidate for next-generation two-dimensional (2D) optoelectronic material, bismuth oxyselenide (Bi₂O₂Se) nanoplates exhibit many prospects in the application of visible light detection due to their peculiar properties. In this work, we report the photodetection performance of single-crystal 2D Bi₂O₂Se nanoplates grown on SiO₂ based on a ternary-alloy growth model by utilizing chemical vapor deposition (CVD). The Bi₂O₂Se nanoplates were found to have an even and uniform square shape with side lengths up to 15 µm and an approximate thickness of 15 nm. A visible-light photodetector was fabricated based on a CVD-grown Bi₂O₂Se nanoplate, and characterized by a set of illumination experiments using a 400 nm laser at temperatures ranging from 77 to 370 K. The device exhibited superior performance at the temperature of 77 K, with a responsivity of 523 A/W, a specific detectivity of 1.37 × 10¹¹ Jones, a response time of 0.2175 ms, and an external quantum efficiency of 162,119.44%, resulting in high-quality and full-color imaging in the visible spectrum. These results indicate that the single-crystalline Bi₂O₂Se nanoplates have excellent potential in broadband photodetection and non-cryogenic imaging.