Asymmetric contact structure enables fast response of Bi2O2Se photodetectors

The near-infrared (NIR) photodetector is an important component in the realm of photodetectors. Bi2O2Se, with its narrow bandgap of 0.8 eV, has emerged as a promising candidate for NIR detection. However, it exhibits a slower response in this spectral region. An asymmetric electrode structure can effectively separate photogenerated electron-hole pairs by introducing an internal electric field, thereby facilitating faster carrier transport and significantly reducing the response time. In this study, we utilized PdSe2, a semi-metal, as an electrode to construct an asymmetric electrode structure in conjunction with Ti-Au electrode, aiming to enhance the performance of Bi2O2Se NIR photodetectors. The response time of the PdSe2/Bi2O2Se/Ti-Au photodetector was 21 and 16 mu s under 1064 and 1550 nm light sources, respectively, with a responsivity of 121 mA/W at 1064 nm. These findings underscore the potential of this design in advancing infrared detection technology.