We have measured the complex dielectric function, epsilon(E)=epsilon(1)(E)i epsilon(2)(E), of Pb1-xEuxSe in the 1.2-5.0 eV photon-energy range by spe
ctroscopic ellipsometry at room temperature. The Pb1-xEuxSe crystals were g
rown by the conventional Bridgman method (x=0) and by hot-wall epitaxy on (
111) BaF2 substrates at 300 degrees C (0.09 less than or equal to x less th
an or equal to 0.45). The measured epsilon(E) data revealed distinct struct
ures at two critical-point (CP) energies, E-1 and E-2. The second-derivativ
e spectra of the complex dielectric function, d(2)epsilon(E)/dE(2), were an
alyzed using a theoretical model called the model dielectric function. The
CP parameters, such as the CP energy, amplitude, and broadening, as a funct
ion of alloy composition x were fit determined from these derivative analys
es. This parameterization of the CP parameters enabled us to calculate epsi
lon(E) and its related optical constants for optional alloy composition and
photon energy. (C) 1999 American Institute of Physics. [S0021-8979(99)0641
7-8].