Analysis of enhanced absorption in dense silicon nanowire arrays

Abstract

We analyze the absorption of solar radiation by dense silicon nanowire arrays, which are being considered for use in solar cells. Though it is known that these structures absorb sunlight much more efficiently than bulk silicon, the mechanism is complicated and not understood. Using a novel, semi-analytic model, we show that the enhanced absorption can be attributed to a few modes of the array, which couple well to incident light, overlap well with the silicon, and exhibit strong Fabry-Pérot resonances. For some frequencies the absorption is further enhanced by slow light effects. Show more