Optical Properties of Silicon and Germanium Nanowire Fabric

The optical properties of free-standing nonwoven silicon (Si) and germanium (Ge) nanowire fabrics, including diffuse and specular reflectance, diffuse and direct transmittance, and absorptance spectra, were measured using an integrating sphere to account fully for all incident photons. Very thin, 50 μm thick, sheets with ∼90% void volume have extremely high optical densities. They are optically opaque across nearly all wavelengths from...