Peng Luo, Fakun Wang, Jingyu Qu, Kailang Liu, Xiaozong Hu, Kewei Liu, Tianyou Zhai*, Self-Driven Bi2O2Se/WSe2 Van der Waals Heterostructure Photodetectors with High On/Off Ratio and Fast Response, Advanced Functional Materials 2021, 31, 2008351.
https://doi.org/10.1002/adfm.202008351.
Abstract: Benefiting from the superior electron mobility and good air-stability, the emerging layered bismuth oxyselenide (Bi2O2Se) nanosheet has received considerable attentions with the promising prospects for electronics and optoelectronics applications. However, the high charge carrier concentration and bolometric effect of Bi2O2Se give rise to the high dark current and relatively slow photoresponse, which severely impedes further improvement of the performance of Bi2O2Se based photodetectors. Here, we report a WSe2/Bi2O2Se van der Waals p-n heterostructure with a pronounced rectification ratio of 105 and a low reverse dark current of 10-11 A, as well as an enhanced light on/off ratio up to 618 under 532 nm light illumination. The device also exhibited a fast response speed of 2.6 ms and a broadband detection capability from 365 nm to 2000 nm due to the efficient charge separation and strong interlayer coupling at the interface of the two flakes. Importantly, the built-in potential in the WSe2/Bi2O2Se heterostructure offered a competitive self-powered photodetector with the light on/off ratio above 105 and a photovoltaic responsivity of 284 mA/W. Our WSe2/ Bi2O2Se heterostructure shows promising potentials for high-performance self-driven photodetector applications.
