Gold‐Coated Silicon Quasi‐Periodic Inverted Pyramid Arrays as Ultra‐Broadband Absorbers for High‐Efficiency Hot Carrier Schottky Solar Cells

Hot carrier Schottky junction silicon solar cells offer a promising route toward high‐efficiency photovoltaics by exploiting plasmonic carrier excitation and sub‐bandgap absorption. Here, lithography‐free gold‐coated silicon quasi‐inverted pyramid arrays (SiQIPAs) are fabricated as ultra‐broadband light absorbers operating across the 300–2000 nm range. The optimized 10 nm Au layer enables an exceptionally low reflectance of 2.49% within the main silicon absorption region (300–1000 nm) and 17.34% in the sub‐bandgap range (1100–2000 nm), corresponding to the average absorption values of 97.47% and 71.43% in the 300–1000 and 1100–2000 nm range, respectively, with the lowering in the transmission. The optimized 10 nm Au‐coated SiQIPA sample is capable of exciting the localized surface plasmon resonance for ultra‐broadband absorption, as further supported by finite element simulations. Theoretical analysis using the experimental absorption data of 10 nm Au‐coated SiQIPA sample predicts a short‐circuit current density ( J SC ) of 57.81 mA cm −2 and a power conversion efficiency of 36.76% under ideal carrier collection conditions, surpassing the Lambertian and Shockley–Queisser limits, respectively. These findings highlight the synergistic role of optical field confinement and hot carrier dynamics in driving next‐generation, ultrathin, high‐efficiency silicon solar cells.