Dual-Resonance Metamaterial-Enhanced Thin-Film Transistor Photodetectors for UV–Vis–NIR Broadband Detection: A Computational Study

We investigate the impact of silver metamaterial configurations on the performance of thin-film transistor (TFT)-based photodetectors operating across the ultraviolet (UV), visible (Vis), and near-infrared (NIR) spectra using a silicon active layer. Broadband UV–Vis–NIR photodetectors are increasingly required for applications such as environmental monitoring, material inspection, wearable electronics, and biomedical sensing. Conventional silicon TFTs are primarily sensitive in the Vis region, whereas their efficiency in the UV and NIR regions are inherently limited. This restriction motivated the development of broadband architectures capable of simultaneous UV–Vis–NIR detection rather than relying on separate detectors for each spectral range. To overcome these limitations, we introduced silver-based metamaterials onto the silicon active layer for increased photodetector light absorption, thereby enhancing the device efficiency. We found that incorporating silver split-ring resonators (SRRs), ring nanoparticles (RNPs), and ring nanohole (RNH) resonators as metamaterials on the silicon active layer increases light absorption, particularly close to the silicon bandgap. The SRR enhances free-electron generation via LC resonance, whereas the RNP and RNH structures leverage both LC resonance and localized surface plasmon resonance (LSPR), thereby increasing both light absorption amplitude and bandwidth from UV to NIR. Under an incident intensity of 75 W/m² across 100–1200 nm, the simulated average output currents were 0.5 (dark), 0.63 μA (bare silicon under illumination), and 0.65, 0.66, and 0.67 μA for SRR-, RNP-, and RNH-based devices, respectively. The RNH-based structure exhibited the highest efficiency, highlighting its potential as a broadband high-performance platform for next-generation optoelectronic systems.