Far-infrared dielectric constant of porous silicon layers measured by terahertz time-domain spectroscopy

Porous silicon (PS) has photo and electroluminescence properties, but experimental data about its dielectric constant is scarce. The refractive index and absorption of PS layers in the millimetric and submillimetric wavelength have been measures, using the terahertz time-domain method. The refractive index of PS is well described by mixture theories for the porosity range of 55-76%, where the refractive index of bulk silicon is a main parameter.