This paper contains a combined experimental and
simulation study of the effect of Al and AlInP nanoparticles on
the performance of multi-junction solar cells. In particular, we
investigate oblique photon scattering by the nanoparticle arrays
as a means of improving thinned subcells or those with low
diffusion lengths, either inherently or due to radiation damage.
Experimental results show the feasibility of integrating
nanoparticle arrays into the ARCs of commercial
InGaP/InGaAs/Ge solar cells, and computational results show
that nanoparticle arrays can improve the internal quantum
efficiency via optical path length enhancement. However, a
design that improves the external quantum efficiency of a stateof-the-art
cell has not been found, despite the large parameter
space studied. We show a clear trade-off between oblique
scattering and transmission loss, and present design principles
and insights into how improvements can be made.