Fast Photothermoelectric Response in CVD-Grown Two-Dimensional Bi₂O₂Se Nanoplates

As an emerging two-dimensional (2D) semiconductor material, layered Bi2O2Se exhibits tremendous potential applications in the field of optical devices due to its high electron mobility, exceptional optical response, and remarkable air stability. In this study, high-quality Bi2O2Se nanoplates were grown on a fluorophlogopite mica (f-mica) substrate via a chemical vapor deposition approach. A high-quality two-terminal Bi2O2Se device is fabricated by traditional electron beam lithography, which displays linear current–voltage characteristics. The Bi2O2Se device exhibits an ON/OFF ratio of 104 as well as n-type semiconductor characteristics. A maximum responsivity of 0.029 A W–1 and a fast photoresponse time of 35–42 μs under 638 nm laser illumination are discovered. Spatially resolved scanning photocurrent microscopy is conducted, which indicates that the photothermoelectric effect should be the dominant contribution for the observed photocurrent in the Bi2O2Se device. This study paves the way for developing high-performance photoelectron devices based on Bi2O2Se materials.