Boosting Field Emission in Black Silicon via Gold Nanoparticle Decoration Guided by High-Fidelity 3D Morphological Simulation

Overcoming the inherent limitations of nanostructured black silicon (BS) for efficient field emission (FE) cathodes remains a significant challenge. Despite its promising nanostructured morphology with sharp, controllable tips amenable to mass production, BS suffers from a high work function (∼4.5 eV), poor electrical conductivity, and inadequate heat dissipation. These material properties lead to high threshold fields, unstable emission, and low current densities. Here, we demonstrate a simple and effective strategy to dramatically enhance the FE performance of BS through surface modification with gold nanoparticles (Au-NP). Critically, we overcome the complexity of simulating highly disordered BS emitters on nonplanar surfaces by developing a high-precision three-dimensional (3D) modeling approach based on parametrized scanning electron microscope (SEM) images. This model accurately captures the intricate surface morphology and enables the exploration of the electric field and current characteristics under varying Au-NP parameters. Guided by the simulations, we experimentally fabricated gold nanoparticle-decorated BS (Au-NP@BS) cathodes and achieved a significantly enhanced emission current density up to 4.01 mA/cm2. The close agreement between simulation predictions and experimental FE measurements validates this high-fidelity 3D modeling approach. This work not only provides a practical route to high-performance BS cathodes but also establishes a powerful computational tool for accurately mapping and optimizing the FE properties of complex, large-scale disordered nanostructures.