300–2200 nm Broadband Si Schottky Photodetectors With Ultra-Low Dark Current (<10 nA/cm2) via Al2O3/SiOx Interface Engineering

This study demonstrates a silicon (Si)-based near-infrared (NIR) photodetector achieving ultralow dark current density (7.5×10⁻⁹ A/cm² at −2 V) and ultrawide wavelength photoresponse (300–2200 nm) through an engineered ITO/Al₂O₃/SiO_x/n-Si Schottky photodetector. By integrating an Al₂O₃/SiO_x bilayer interface, the Schottky barrier height (SBH) of this structure is elevated to 0.87 eV, suppressing dark current by nearly six orders of magnitude compared to a conventional ITO/n-Si device. Owing to its ultralow dark current characteristic, the device exhibits high sensitivity with a specific detectivity of 1.17×10¹² Jones at 532 nm. Remarkably, the device exhibits self-powered operation at zero bias with robust stability and achieves room-temperature optical imaging up to 2200 nm. The Si-substrate-based architecture not only ensures seamless integration with complementary metal-oxide-semiconductor (CMOS) fabrication processes but also highlights cost-effectiveness.