Improving Silicon Photodetectors NIR Responsivity via Hybrid Opto-Plasmonic Resonances

During the past twenty years, the photoelectronic industry has grown to incredible proportions, producing devices that have become staples of our every-day life and have completely transformed the way we live. The core technology at the heart of the photoelectronic industry is the “photodetector”. Traditional photodetectors’ performance has dramatically improved after the introduction of nanostructured materials. Among these enhancement materials, plasmonic metal structures are of particular interest due to their peculiar and useful properties, such as optical resonances, high bulk, and surface sensitivities and sub-wavelength light confinement. Plasmonic materials can lead to the development of detectors for novel applications in nano-photonics, biosensing, integrated optics, and lasers. Here, we want to propose an evolution of the common “waveguide detector” design that enables the fabrication of a plasmonic structure, capable of enhancing the absorption efficiency at any desired wavelength, on top of the active area of any kind of traditional semiconductor-based photodetector, including single-photon silicon photomultipliers (SiPMs). Our structure works in a simple tri-layer configuration, metal-dielectric-semiconductor (MIS), by coupling an optical resonance phenomenon with a traditional plasmonic resonance excited on the metal/dielectric interface by means of hole-coupling transmission through an open-slits type of grating. The resulting hybrid opto-plasmonic resonance can drastically enhance the responsivity of a photodetector.