Broadband (300-2200 nm) All-Si Schottky Photodetector with Ultralow Dark Current for NIR Communication and Imaging Applications

This work presents a near-infrared (NIR) Schottky photodetector based on an ITO/Au nanoparticles (NPs)/Al₂O₃/Silicon (Si) architecture, exhibiting exceptional dark current suppression (0.4 nA at -2 V) and a broadband photodetection spanning ultraviolet to extended NIR wavelengths (300-2200 nm). The integration of an Au NPs/Al₂O₃ interlayer at the ITO/Si interface effectively enhances the Schottky barrier height to 0.81 eV, leading to a nearly five-order-of-magnitude reduction in dark current compared with a conventional ITO/Si photodetector. The device achieves self-powered characteristics under zero bias and demonstrates practical room-temperature applications in 1550 nm optical communication systems and 2200 nm imaging scenarios. This design establishes a promising pathway for enabling high-performance NIR photodetectors with ultralow dark current and broadband spectral adaptability.