Optical absorption enhancement in disordered vertical silicon nanowire arrays for photovoltaic applications

Optical properties are numerically investigated for vertically aligned silicon nanowire arrays with three types of structural randomness, i.e., random position, diameter, and length. Nanowire arrays with random position show slight absorption enhancement, while those with random diameter or length show significant absorption enhancement, which is attributed to the stronger optical scattering in a random structure. Our results indicate that structural randomness in vertical nanowire arrays will not destroy but rather can further enhance optical absorption compared to ordered nanowire arrays.