Air‐Stable Violet Phosphorus/MoS₂ van der Waals Heterostructure for High‐Responsivity and Gate‐Tunable Photodetection

Abstract Violet phosphorus (VP), a newly emerging elemental 2D semiconductor, with attractive properties such as tunable bandgap, high carrier mobility, and unusual structural anisotropy, offers significant opportunities for designing high‐performance electronic and optoelectronic devices. However, the study on fundamental property and device application of 2D VP is seriously hindered by its inherent instability in ambient air. Here, a VP/MoS₂ van der Waals heterostructure is constructed by vertically staking few‐layer VP and MoS₂, aiming to utilize the synergistic effect of the two materials to achieve a high‐performance 2D photodetector. The strong optical absorption of VP combining with the type‐II band alignment of VP/MoS₂ heterostructure make VP play a prominent photogating effect. As a result, the VP/MoS₂ heterostructure photodetector achieves an excellent photoresponse performances with ultrahigh responsivity of 3.82 × 10⁵ A W^–1, high specific detectivity of 9.17 × 10¹³ Jones, large external quantum efficiency of 8.91 × 10⁷ %, and gate tunability, which are much superior to that of individual MoS₂ device or VP device. Moreover, the VP/MoS₂ heterostructure photodetector indicates superior air stability due to the effective protection of VP by MoS₂ encapsulation. This work sheds light on the future study of the fundamental property and optoelectronic device application of VP.