The complex dielectric function of Cd1-xFexTe (x=0, 0.02, and 0.04) single
crystals were measured by spectroscopic ellipsometry in the 1.5 similar to
4.5 eV photon energy range at room temperature. The measured epsilon(omega)
data revealed distinct structures at energies of the E-1 and E-1 + Delta(1
) critical points (CPs). These data were analyzed by fitting the second-der
ivative spectra (d(2)epsilon/d omega(2)) with a. theoretical model, i.e., t
he standard critical point (SCP) line shapes. It was found that the SCP mod
el explained the measured derivative spectra successfully. The CP energies
and the Lorentzian broadening(Gamma) were determined.