Plasmon-enhanced sensitive photodetection using plasmonic noble metals has been widely investigated; however, aluminum (Al)-based photoelectric conversion concurrently utilizing photonic and plasmonic approaches is less explored. Here, photodetection driven by quasi-localized plasmon resonance (QLPR) is investigated. Concurrent photonic and plasmonic contributions to strong absorption in the active region require delocalized, slow-propagating resonant electric field to occur around the peripheries of Al nano-structures and depend on the spatial distribution of diffraction efficiencies of all space harmonics. Efficiency limits are shown to be largely determined by the spatial degrees of freedom and the associated traveling distances of hot electrons during carrier transport. With strong absorption and relatively high reaching-emission probabilities structured in the same region, the measured responsivity and the external quantum efficiency of the fabricated device at 638.9 nm are 4.1889 μA/mW and 0.8129% at -0.485 V, respectively. Our results provide physical insights into related problems and may offer a route to more efficient, hot-carrier based photoelectric conversion devices.