Broadband metamaterial absorber based on photon-assisted tunneling diode for solar power generation

In this work, we introduce a metamaterial absorber designed for the full solar spectrum and investigate its potential for power generation. This absorber features a periodic array structure based on a metal-oxide-oxide-semiconductor (MOOS) tunneling diode, enabling simultaneous absorption and rectification, thus functioning as a rectifying antenna (rectenna). We use numerical simulations to obtain the absorption spectrum and electromagnetic field distributions, and calculate the MOOS tunneling current density using photon-assisted tunneling theory. The proposed metamaterial absorber demonstrates near-perfect broadband absorption, averaging 97.4% from 0.3 to 2.5 μm. Under AM1.5 illumination, the rectenna's local electric field figure of merit exceeds 10 4 , generating a net DC current of 39.2 mA/cm 2 . The analysis of the physical mechanisms reveals that high absorption is attributed to the resonant coupling of surface-guided modes and diffraction modes, while the enhanced electric field results from localized surface plasmon resonance at the tunneling barrier. This study is expected to advance the development of broadband metamaterial absorbers and pave the way for efficient solar energy harvesting and generation.