Interface Engineering with Graphene Contacts in VP/MoS <b> ₂ </b> Heterostructures for High-Performance, Durable, and Multispectral Photodetection

Efficient photocarrier separation and collection are essential for high-performance photodetectors. In van der Waals (vdWs) heterostructures, carefully engineering the interfaces and built-in electric fields is an effective strategy to maximize device performance. Here, we present a high-performance photodetector based on a vertically stacked few-layer graphene/violet phosphorus/MoS₂ (FLG/VP/MoS₂) vdWs heterostructure, which exhibits significantly enhanced performance across a broad spectral range from ultraviolet (275 nm) to near Infrared (808 nm). The photodetector achieves a responsivity of up to 8.8 × 10⁴ A/W with an external quantum efficiency of 1.81 × 10⁷─values over 5 orders of magnitude higher than those of a bare VP/MoS₂ device (∼0.52 A/W and 7.68%, respectively). It also exhibits a fast photoresponse (rise time of ∼1.5 ms) and notable polarization sensitivity (dichroic ratio of ∼1.075). Moreover, the device maintains stable performance of over at least 100 on-off cycles, highlighting its excellent operational durability. First-principles calculations further corroborate the strong interlayer coupling and structural stability of the device interface, providing theoretical support for the observed durability and photodetection mechanism. Collectively, this work positions the FLG/VP/MoS₂ vdWs heterostructure as a promising platform for high-performance, broadband, and polarization-sensitive photodetection in advanced optoelectronic applications.