2D Bi₂O₂Te Obtained by CVD as a Near-Infrared Photodetector

Bi 2 O 2 Te, a rapidly emerging material in the two-dimensional (2D) realm, demonstrates exceptional promise for applications in next-generation electronic and optoelectronic devices. Benefiting from its unique properties, such as ultra-high carrier mobility and small energy gaps of 0.21 eV, Bi 2 O 2 Te is competent for near-infrared (NIR) detection. This work achieved the controllable growth of 2D Bi 2 O 2 Te nanoplates with a thin vertical thickness of 22 nm on mica substrates via a conventional CVD process by changing the precursor temperature. Meanwhile, the morphology variation at different locations on the mica substrate was investigated and explained through first-principles calculations. Furthermore, we fabricated NIR photodetectors based on the CVD-grown 2D Bi 2 O 2 Te nanoplates. The NIR photodetectors presented excellent performance, including a high photoresponsivity of 111.23 A/W, a high external quantum efficiency of 16609%, a specific detectivity of 1.23 × 10 11 Jones, and a fast photoresponse speed ( t rising / t reset ) of 6.5 ms/6.2 ms at a wavelength of 830 nm. These results demonstrate that 2D Bi 2 O 2 Te nanoplates are promising candidates for NIR photodetectors, offering fast response speed, high detectivity, and responsivity.