532–2200 nm Si Schottky Photodetectors Featuring Nonuniform Barrier Layers

The internal photoemission (IPE) effect in silicon (Si) Schottky photodetectors offers a promising route to overcome the inherent bandgap limitation of Si and achieve efficient near-infrared (NIR) optical detection. However, conventional Si Schottky photodetectors, characterized by uniform Schottky barrier layers, exhibit restricted spectral response due to fixed barrier height constraints. In this work, we demonstrate a novel ITO/Au nanoparticles (NPs)/n-Si structure Schottky photodetector feat uring a precisely engineered nonuniform Schottky barrier modulation layer. The densely packed Au NPs are precisely manipulated to fabricate a ‘non uniform’ modulation layer of Schottky barrier, resulting in a high overall barrier height (0.71 eV) for effective suppression of dark current (33 nA at room temperature). Moreover, the light can be effectively localized in the low-barrier-height region (0.52 eV) when exposed to illumination, thus widening the photoresponse cut-off wavelength. This architecture extends the photoresponse range from visible (532 nm) to short-wavelength infrared (2200 nm), achieving room-temperature optical imaging up to 2200 nm. In addition, the device has self-bias characteristics and strong temperature adaptability, enabling stable working under extreme environmental conditions (193 and 363 K). The proposed design provides a cost-effective, fabrication-friendly solution for all-Si-based broadband photodetection in NIR communication bands, demonstrating significant potential for next-generation optoelectronic applications.