Graphene-mediated interfacial engineering in MoS2/Gr/SnS van der Waals heterostructures for high-performance self-powered broadband photodetection

초록

Self-powered photodetectors based on two-dimensional van der Waals (vdW) heterostructures have attracted considerable attention for low-power optoelectronic applications. However, their performance is often limited by inefficient interfacial charge transport and trap-assisted recombination. Herein, we report a high-performance self-powered photodetector based on a monolayer MoS2/graphene/multilayer SnS (MoS2/Gr/SnS) n–g–p vdW heterostructure fabricated via a dry-transfer process. The graphene interlayer facilitates interfacial charge transport, enabling self-powered photoresponse at representative wavelengths spanning 365–850 nm from the UV to the near-infrared region. Under 365 nm illumination at zero bias, the device achieves a responsivity of 1.26 A/W, a specific detectivity of 1.27 × 1012 Jones, an external quantum efficiency (EQE) of 428%, and fast rise and decay times of 23.3 and 4.9 ms, respectively. Under a drain bias of + 1 V, the responsivity and detectivity are further increased to 608 A/W and 2.35 × 1013 Jones, respectively. Kelvin probe force microscopy and energy-band analysis indicate a step-like interfacial band alignment with aligned built-in electric fields, providing a favorable pathway for carrier separation and transport. Comparative device measurements further demonstrate improved carrier collection after graphene insertion. This work demonstrates an effective graphene-mediated interfacial engineering strategy for enhancing self-powered photodetection in vdW heterostructures. © 2026 Elsevier B.V.

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