Studies of Spectroscopic Ellipsometry in Cd$_{1-x}$Mn$_x$Te(0.0 ≤ x ≤0.77) Single Crystals

We used spectroscopic ellipsometry to investigate in the energy range of 1.5 ? 5.5 eV at room temperature the dielectric function of Cd1-xMnxTe(0.0 ≤ x ≤0.77) crystals grown using a vertical Bridgman method. The critical point (CP) parameters of the E0, E1,, and E1+△1 structure were determined from an analysis of the numerically-obtained second derivatives of the original pseudodielectric function spectra. The E1 and E1+ △1 energies decreased with increasing Mn composition x due to a hybridization of the valence and the conduction bands in CdTe with Mn 3d levels. The dependence of such CP parameters on the Mn mole fraction x is discussed.ope