Investigation of charge transport and band alignment of MoS2-ReS2 heterointerface for high performance and self-driven broadband photodetection

Two dimensional (2D) van der Waals heterostructures are becoming one of the ascendant research areas for semiconducting device application owing to their remarkable optoelectronic properties, which allows more functioning ability beyond its individual constituent. 2D layered materials can be easily integrated and form heterostructure due to the dangling bond free surfaces. However, for novel optoelectronic device applications, the understanding of charge carrier dynamics at the interface of heterostructures is critical and essential. Here, we demonstrate the charge transport behaviour and energy level band alignment at MoS2-ReS2 heterointerface. Interlayer coupling and charge transport behaviour are investigated by Raman and photoluminescence spectroscopy. The photoelectron spectroscopy confirms type Ⅱ band alignment between MoS2-ReS2 interface, which is required for efficient separation and transportation of charge carriers. As a proof of concept, a highly sensitive, self-biased broadband photodetector is fabricated with a responsivity of 42.61 A/W at a low bias of 1 V under the illumination of 800 nm, which is 16 fold higher than the reference pristine MoS2 photodetector. Moreover, fast rise/decay transient photoresponse (20/19 ms) strongly advocate the spatial separation of charge carriers across the interface. Our proposed work establishes the MoS2 and ReS2 as promising candidates for next-generation broadband photodetector applications.