Optical properties of Cd1−xMgxTe (x=0.00, 0.23, 0.31, and 0.43) alloy films

Abstract

Pseudodielectric functions 〈ε〉 of Cd1−xMgxTe ternary alloy films of compositions x=0.00, 0.23, 0.31, and 0.43 have been determined from 1.5 to 6.0 eV by spectroscopic ellipsometry. We obtain approximations to the bulk dielectric functions ε by performing wet-chemical etching to remove overlayers and using parametric modeling to remove interference oscillations below the fundamental band gap. The values of the E0, E0+Δ0, E1, E1+Δ1, E2, and E0′ critical point energies and their x dependences at room temperature were determined from numerically calculated second energy derivatives of these data.