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

Pseudodielectric functions <epsilon> 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 epsilon 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 E-0, E-0+Delta(0), E-1, E-1+Delta(1), E-2, and E-0(') critical point energies and their x dependences at room temperature were determined from numerically calculated second energy derivatives of these data. (C) 2004 American Institute of Physics.