The optical (free-carrier) absorption of a hole-electron plasma in silicon

The near-IR absorption of a heavily injected silicon p-i-n diode has been measured. This is thought to be the first comprehensive measurement of the free-carrier absorption of a hole-electron plasma, and it behaves as expected with temperature, injection level and wavelength.

However, the absolute value of the absorption is higher than can be accounted for by ionized impurity scattering mechanisms by a factor of about 2.