Engineering the optical reflectance of randomly arranged self-assembled semiconductor nanowires

Metasurfaces made of arrays of vertically aligned semiconductor nanowires are suitable platforms for light management in optical and photonic applications. Here we report a design approach aimed at engineering the optical behavior of semiconductor nanowire ensembles randomly displaced on the substrate, in order to enhance modulation effects in their optical reflectance response. By resorting to analytical and numerical simulations we demonstrate that the combined implementation of a multi-shell layering together with a tapered designing on the individual nanowire offer new opportunities to tailor the optical reflectance oscillations in this kind of architectures. The simulation insights were compared to experimental results reported for self-assembled GaAs nanowires and GaAs/AlGaAs core-shell nanowires. The proposed approach is especially promising for epitaxially grown semiconductor nanowires, where the suggested design modifications can be easily implemented during the nanostructure growth.