High-Performance Broadband Photodetector Based on Monolayer MoS2 Hybridized with Environment-Friendly CuInSe2 Quantum Dots

Monolayer MoS2, a direct bandgap transition metal dichalcogenide (TMD), has attracted worldwide attention in electronics and optoelectronics. However, the performance of photodetectors based on monolayer MoS2 is restricted to a weak optical absorption, narrow absorption range, and persistent photoconductance. Herein, benefiting from an easy solution process, high light absorption coefficient, and wide absorption range, environment-friendly CuInSe2 quantum dots (QDs) are hybridized with monolayer MoS2 for high-performance broadband photodetectors. Owing to the favorable type-II energy band alignment of MoS2/CuInSe2-QDs, the hybrid photodetector exhibits a broadband photoresponse from the ultraviolet to near-infrared region, with an ultrahigh photoresponsivity of 74.8 A/W at 1064 nm, and compared with those of the pristine MoS2 device, the photoresponsivity and specific detectivity in the ultraviolet–visible region were enhanced by about 30 and 20 times, respectively. Furthermore, the formed depletion region at the MoS2/CuInSe2-QDs interface can significantly increase the photoresponse speed, and the accumulated holes in the QD side induce a strong photogating effect to improve the photoresponsive characteristics of the hybrid photodetector. Our work opens up opportunities for fabricating high-performance monolayer TMD-based broadband photodetectors.