Interaction of Light with Si Nanowire Films

The optical properties of silicon nanowire films fabricated on bulk Si and glass substrates are reported. The total reflectance of aligned nanowire arrays formed by a wet etch process on bulk Si is lower than the control over all wavelengths below the bandgap, varying from ~1% at 300 nm to les 10% at 1,000 nm. Similar results are observed for nanowire thin films. The observed reflectance is related to the so-called "moth-eye" effect. Modeling work shows strong resonance of light within and between nanowires