Broadband, Polarization-Sensitive, and Self-Powered High-Performance Photodetection of Hetero-Integrated MoS 2 on Lithium Niobate

Abstract

High-performance photodetectors hold promising potential in optical communication and imaging systems. However, conventional counterparts are suffering narrow detection range, high power consumption, and poor polarization sensitivity. Characteristics originating from switchable polarization in ferroelectrics can be used to optimize the photo-to-electric procedure and improve the photodetection performance. In this regard, we constructed a configuration by integrating 2-dimensional molybdenum disulfide (MoS 2 ) with ferroelectric lithium niobate (LiNbO 3 ), resulting in the MoS 2 /LiNbO 3 heterostructured photodetector. Benefiting from the pyroelectric effect of LiNbO 3 , the limitation of bandgap on the detection range can be broken, thus broadening the response band of the detector to 365 to 1,064 nm, as well as enabling the self-powered characteristic. Meanwhile, high carrier mobility and decent light absorbance of MoS 2 introduce robust light-matter interactions with the underlying LiNbO 3 , leading to ultrafast rise/fall times of ≈150 μs/250 μs and switching ratios of up to ≈190. Moreover, the highest responsivity, specific detectivity, and external quantum efficiency achieved were 17.3 A·W −1 , 4.3 × 10 11 Jones, and 4,645.78%, respectively. Furthermore, because of the anisotropy of the spontaneous-polarized LiNbO 3 substrate, the photocurrent of the device achieved a dichroic ratio of 7.42, comparing favorably to most MoS 2 -based photodetectors. This work demonstrates the integration potential between ferroelectric LiNbO 3 and 2-dimensional materials for high-performance photodetection.