Enhanced photocurrent and responsivity of Bi2O2Se nanosheet near-infrared photodetector by in situ surface growth of Te nanowires

The intrinsically weak optical absorption and limited photocarrier separation of atomically thin two-dimensional (2D) materials often limit the photodetector performance. Here, we report an in situ surface growth strategy for preparing a Bi2O2Se/Te heterojunction via a low-temperature chemical vapor deposition method. One-dimensional Te nanowires directly grow on 2D Bi2O2Se nanosheets, forming a clean van der Waals interface and enhancing optical absorption capacity. The Bi2O2Se/Te heterostructure exhibits excellent optoelectronic performance, including an enhanced photocurrent of 1.12 μA, a high responsivity of 50 A/W, and a fast response speed of 32/>168 ms. The enhanced photocurrent and responsivity arise from the efficient electron injection from Te to Bi2O2Se, and hole trapping at the heterointerface. This work demonstrates a non-destructive approach for preparing high-quality heterojunctions and provides an effective pathway for next-generation high-performance near-infrared photodetectors.