Reflectivity of disordered silicon nanowires

Disordered silicon nanowire mats have high diffuse optical reflectivity, in striking contrast to the low reflectivity of orientationally ordered nanowires. The reflectivity decreases with increasing photon energy across the visible and near infrared spectrum due to absorption in the nanowires. A simple model is used to estimate that the incident photon interacts with up to 20 nanowires before being reflected. A thin coating of hydrogenated amorphous silicon enhances the nanowire absorption.