2D-material-based photodetectors enhanced by plasmonic nanostructures can support responsivity/detectivity several orders higher than commercial photodetectors, drawing extensive attention as promising candidates for the next-generation photodetectors. However, to boost the nanostructure-enhanced 2D photodetectors into real-world applications, crucial challenges lie in the design of broadband enhancing nanostructures and their scalable and position-controllable fabrication. Here, based on a broadband resonant plasmonic disk array fabricated by a scalable and position-controllable technique (direct writing photolithography), we present a visible-near infrared (405–1310 nm) 2D ${\mathrm{WS}}_2$ photodetector, whose detectivity is up to $3.9\times {10}^{14}$ Jones, a value exceeding that of the previous plasmon-enhanced 2D photodetectors. The broadened spectral response range and the high detectivity originate from the hot electron injection, optical absorption enhancement, and strain effect supported by the plasmonic array. Furthermore, the designed plasmonic 2D photodetector supports self-powered photodetection, indicating promising potential in energy-free and portable optoelectronic systems. Our results demonstrate an effective method to construct high-performance broadband photodetectors, which can facilitate the development of 2D photodetectors in commercial applications.