Optical properties of PbSe

The real (ε1) and imaginary (ε2) parts of the dielectric function, ε(E)=ε1(E)+iε2(E), of PbSe have been measured by spectroscopic ellipsometry in the 1.15–5.4 eV photon-energy range at room temperature. The measured spectroscopic-ellipsometry data reveal distinct structures at three critical-point energies (E1, E2, and E3). These data are analyzed using the two theoretical models, namely, the model dielectric function and standard critical-point model. It is found that both the model dielectric function and standard critical-point model successfully explain the measured derivative spectra, d2ε/dE2. It is also found that the model dielectric function shows excellent agreement with the experimental ε(E) spectra, but the standard critical-point model does not. Dielectric-related optical constants, such as the complex refractive index, absorption coefficient, and normal-incidence reflectivity, of PbSe are also presented.