We report a novel graded refractive index antireflection coating for III/V quadruple solar cells based on bottom-up grown tapered GaP nanowires. We have calculated the photocurrent density of an InGaP–GaAs–InGaAsP–InGaAs solar cell with a MgF2/ZnS double layer antireflection coating and with a graded refractive index coating. The photocurrent density can be increased by 5.9% when the solar cell is coated with a graded refractive index layer with a thickness of View the MathML source. We propose to realize such a graded refractive index layer by growing tapered GaP nanowires on III/V solar cells. For a first demonstration of the feasibility of the growth of tapered nanowires on III/V solar cells, we have grown tapered GaP nanowires on AlInP/GaAs substrates. We show experimentally that the reflection from the nanowire coated substrate is reduced and that the transmission into the substrate is increased for a broad spectral and angular range.

Elsevier B.V.
Sol. Energy Mater. Sol. Cells

Diedenhofen, S. L., Grzela, G., Haverkamp, E., Bauhuis, G., Schermer, J., & Gómez Rivas, J. (2012). Broadband and omnidirectional anti-reflection layer for III/V multi-junction solar cells. Sol. Energy Mater. Sol. Cells, 101, 308–314. doi:10.1016/j.solmat.2012.02.022