Substrate interface plasmonic resonance mode of metal nanodisk on high-index wide bandgap semiconductors: Overlapping frequency from near-UV to VUV band

Due to large near-field enhancement and strong light scattering and absorption effects, metal plasmonic nanoparticles offer a potential route for advancing the performance of semiconductor photodetectors (PDs). However, the common high-index semiconductor substrate has been limited in exploring reliable plasmonic resonance structures to achieve both the substrate interface field enhancement and deep UV plasmonic resonance. Here, by tuning particle size, particle height, and the gap of periodic Al and Be nanodisk arrays on the high-index wide bandgap semiconductor layer, we explore a reliable approach to optimize the plasmonic resonance nanostructures for achieving strong near-field enhancement at the semiconductor–metal interface, meanwhile gaining plasmonic resonance wavelength covering the total UV band. Using the smaller nanodisk size, the suitable nanodisk height, and the closely arranged nanodisk array, the substrate–Al particle interface plasmonic structures are applied to precisely match the resonance wavelength with three bandgaps of semiconductors (GaN, Al0.2Ga0.8N, and Ga2O3) and therefore could be a suitable candidate for the relevant plasmonic-assisted PDs. This substrate interface mode with VUV resonance energy is further investigated from a metal Be nanodisk array on an AlN substrate. Moreover, wafer-scale Al nanodisk arrays on GaN and silicon substrates are fabricated, and the obvious optical properties of interface plasmonic resonance are confirmed by the experimental reflectance and photoluminescence measurements of Al NP arrays on a GaN substrate.