  Over the last decade, plasmonic antireflecting nanostructures have been
extensively studied to be utilized in various optical and optoelectronic
systems such as lenses, solar cells, photodetectors, and others. The growing
interest to all-dielectric photonics as an alternative optical technology along
with plasmonics motivates us to compare antireflection properties of
all-dielectric and plasmonic nanoparticle coatings based on silver and
crystalline silicon. Our results of numerical simulations for periodic arrays
of spherical nanoparticles on top of amorphous silicon show that both silicon
and silver nanoparticle coatings demonstrate strong anti-reflective properties
in the visible spectral range. In this work, we show for the first time that
blooming effect, that is zero reflection from the structure, with silicon
coatings originates from the interference of electric- and magnetic-dipole
responses of nanoparticles with the wave reflected from the substrate, and we
refer to it as substrate-mediated Kerker effect. For the silver coating, our
results agree with previously observed substrate-induced bi-anisotropy and
blooming, caused by substrate-induced magnetic response. Finally, we
numerically show high effectiveness of silicon and silver coatings for the
application in thin-film photovoltaic elements, which is related to the
suppression of reflection from the high-index substrate and increased light
absorbance in the active layer with coating. Depending on the nanoparticle
size, either silicon or silver coating is more efficient, and overall increase
of absorption up to 30% can be achieved.
