Tuning the Electronic Properties of 2D Bi2O2Se Nanosheets via Te Doping for Enhanced Infrared Photodetection

Doping can effectively adjust the energy band structure of a semiconductor, thereby influencing its electrical and optical properties. In this study, density functional theory is employed to calculate the crystal structure, electronic configurations, energy bands, and optical properties of tellurium-doped Bi 2 O 2 Se (Bi 2 O 2 Se 1-x Te x ), demonstrating that Te substitution lowers the conduction band, reducing the bandgap. Then 2D Bi 2 O 2 Se 1-x Te x nanosheets are synthesized via organic ion template-guided solution growth method, with Te doping controlled by the Te/Se molar ratio. Optical spectroscopy confirmed that tellurium doping significantly modulates the electronic properties of Bi 2 O 2 Se. When the doping molar concentration is 30%, its bandgap decreases to 0.57 eV. Therefore, Bi 2 O 2 Se 1-x Te x nanosheet-based photodetector demonstrates obvious enhancement of the photoelectric response in the near-infrared region. Notably, Bi 2 O 2 Se 0.7 Te 0.3 photodetector demonstrates broadband photosensitivity across 650–1550 nm, with high responsivity of 32.87 A W −1 and enhanced detectivity of 8.89 × 10 9 Jones at 1060 nm. The device also features a short response time of 16.8/11 µs at 1550 nm. Moreover, the photo-response of the detector shows reliable working stability. Finally, the photodetector is utilized for single-pixel imaging, showcasing its high-contrast infrared light detection capability. These results indicate that Bi 2 O 2 Se 1-x Te x is a promising material for high-sensitivity infrared light detection applications.