Broadband photodetection of 2D Bi2O2Se–MoSe2 heterostructure

Due to their unique structure and photoelectrical properties, two-dimensional (2D) materials have attracted enormous attention on next-generation optoelectronic devices. Recently, the newly discovered 2D layered Bi 2 O 2 Se has exhibited outstanding sensitivity and optoelectronic properties. However, the performance of these 2D layered Bi 2 O 2 Se photodetectors can be limited by the high dark currents. The suitable band structure of 2D MoSe 2 can form a type-II heterojunction with Bi 2 O 2 Se, which can reduce the dark current, modulate the interlayer transition energy and induce the charge spatial separation. Herein, we demonstrated a photodetector based on the heterojunction fabricated by van der Waals assembly between Bi 2 O 2 Se and few-layer MoSe 2 , showing visible to near-infrared detection range. Moreover, our results showed that the dark current of this photodetector was significantly reduced and the I on /I off ratio was greatly improved. Importantly, it exhibited a broad detection range from 405 to 808 nm with a responsivity of 413.1 mA W −1 , a high detectivity of 3.7 × 10 11 Jones (at 780 nm) at room temperature. Compared with the 2D Bi 2 O 2 Se photodetector, the photocurrent response and recovery time in the heterojunction photodetector was greatly reduced from 1.92/1.31 to 0.79/0.49 s at room temperature. Our results showed that 2D Bi 2 O 2 Se/MoSe 2 heterojunction has a great potential for broadband and fast photodetection.