Growth of Multilayer WSe₂/Bi₂O₂Se Heterostructures for Photodetection without Lithography

Novel oxychalcogenides, such as Bi2O2Se, have many applications because of their interesting properties such as remarkable hall mobility, the presence of a bandgap, and high air stability. Among them, photodetectors based on Bi2O2Se are one of the best applicable devices. In addition, the Bi2O2Se heterostructure with other 2D materials can enhance the photoresponse of the device. In this study, we successfully fabricated the WSe2/Bi2O2Se heterostructure for photodetector application via in situ pulsed laser deposition. The band alignment of the as-grown WSe2/Bi2O2Se heterostructure was confirmed to be type II, which increases the photoresponse. Furthermore, the WSe2/Bi2O2Se photodetector exhibited an approximately 110% on/off ratio with a photoresponsivity of 0.96 mA/W even without using lithography for its fabrication.