<p>Graphene and III–V semiconductor heterostructures have emerged as promising materials for high-performance photodetectors due to their broadband absorption, ultrafast carrier dynamics, and compatibility with advanced nanophotonic architectures. Leveraging these material strengths, in this work we have designed and analyzed a plasmonic metasurface-integrated graphene/InGaAs heterojunction photodetector to exploit material-driven light–matter interactions. Using COMSOL Multiphysics^®, the optical and electrical responses are systematically analyzed across the C + L band. The proposed device achieves a peak responsivity of 0.82&#xa0;A/W, external quantum efficiency above 90%, and a detectivity of ~ 1.3 × 10¹² Jones at zero bias, supporting self-powered operation. in addition, we demonstrate a 3-dB bandwidth greater than 60&#xa0;GHz and energy consumption less than 0.01 mW (&lt; 1 fJ/bit), representing a major advancement compared to regular graphene/InGaAs structures. The increase in performance comes from the field confinement from plasmon resonance produced by metallic nanodisk metasurfaces, which significantly increase absorption and carrier transport inside the heterostructure. Taken together, these results validate the promise of a metasurface engineered graphene/InGaAs platform for next-generation optoelectronic and integrated photonic devices.</p>