Graded refractive index layers reduce the reflection and increase the coupling of light into a substrate by optical impedance matching at the interfaces. Due to the optical impedance matching, reflections at the interfaces are not possible for a broad wavelength range, rendering this type of anti-reflection coating a promising candidate for III/V multi-junction solar cells. Graded refractive index layers can be modeled using a transfer-matrix method for isotropic layered media. We derive the transfer-matrix method and we show calculations of the reflection from and the transmission into an AlInP layer coated with different anti-reflection coatings. We describe a new type of anti-reflection coating based on tapered semiconductor nanowires and we show reflection and transmission measurements of those kind of anti-reflection coatings on top of different substrates.

Cham: Springer
X. Wang , Z.M. Wang

Diedenhofen, S.L, Vecchi, G, Bauhuis, G, & Gómez Rivas, J. (2014). Broadband and omnidirectional anti-reflection coating for III/V multi-junction solar cells. In X Wang & Z.M Wang (Eds.), High-Efficiency Solar Cells : Physics, Materials, and Devices (pp. 571–595). Cham: Springer.