Line shape of the optical dielectric function

Abstract
A systematic study of the optical dielectric function by spectroscopic ellipsometry and electroreflectance has shown that the proper functional form for the Green’s function for an electron-hole pair in GaAs or CdTe is primarily Gaussian, not Lorentzian as is commonly assumed, although it is primarily Lorentzian for Hg1−xCdxTe. The Lorentzian part of the broadening is shown to measure the alloy, impurity, and defect scattering.