Performance-enhanced WSe₂/Si Schottky photodetectors via charge redistribution driven by magneto-optical interface

Functional interfacial layers in 2D material/Si heterostructures provide an effective route to suppress dark current and enhance photodetector performance. We report the fabrication and optimization of a high-performance Schottky photodetector based on a solution-processed WSe₂/Si junction incorporating terbium iron garnet (Tb₃Fe₅O₁₂, TbIG) as an interfacial layer. The introduction of the TbIG layer significantly suppresses the dark current by nearly 1.5 orders of magnitude at −2 V, attributed to its insulating characteristics and interface passivation. X-ray photoelectron spectroscopy reveals negative binding energy shifts of ∼350 meV for C1s and ∼200 meV for Si2p, confirming interfacial charge redistribution and dipole formation that enhance the effective Schottky barrier height and suppress trap-assisted recombination. Consequently, the optimized device exhibits a 33.63% reduction in ideality factor, a 35.62% decrease in reverse saturation current, and a 5% increase in barrier height, indicating improved junction quality. The photodetector demonstrates self-powered operation with a detectivity of 4.52 × 10¹² Jones, an on/off ratio of 6.61 × 10⁵ at 405 nm, and a fast rise time of 17 ms, remaining stable over 100 illumination cycles and 28 days under ambient conditions. These results highlight the potential of TbIG-assisted solution-processed WSe₂/Si photodetectors for low-cost, large-area, and high-sensitivity optoelectronic applications.