Tunable reflection minima of nanostructured antireflective surfaces

TLDR

Broadband antireflection schemes based on moth‑eye subwavelength pillar arrays can achieve very low reflectance and are applicable to solar cells, photodetectors, and stealth technologies. The study demonstrates that rigorous coupled‑wave analysis can accurately model the reflectance behavior of these nanostructured antireflective surfaces. This modeling approach allows exploration of how variations in pillar height, period, and shape influence reflectance. The analysis identifies low‑reflectance regions whose extent depends on pillar shape, shows that their wavelength ranges can be shifted by altering the array period, and demonstrates that these spectral features can be tailored for optimal performance to match a specific application’s input spectrum.

Abstract

Broadband antireflection schemes for silicon surfaces based on the moth-eye principle and comprising arrays of subwavelength-scale pillars are applicable to solar cells, photodetectors, and stealth technologies and can exhibit very low reflectances. We show that rigorous coupled wave analysis can be used to accurately model the intricate reflectance behavior of these surfaces and so can be used to explore the effects of variations in pillar height, period, and shape. Low reflectance regions are identified, the extent of which are determined by the shape of the pillars. The wavelengths over which these low reflectance regions operate can be shifted by altering the period of the array. Thus the subtle features of the reflectance spectrum of a moth-eye array can be tailored for optimum performance for the input spectrum of a specific application.