Optical properties of ZnSe and Zn0.87Mn0.13Se epilayers determined by spectroscopic ellipsometry

The semimagnetic ternary semiconductor material ZnMnSe is a suitable candidate for the use in optoelectronic devices either as a spin aligner or a waveguiding layer. In our work we are studying the optical properties of Zn1-xMnxSe layers grown on GaAs (001) substrates by molecular beam epitaxy. We present the complex dielectric function obtained by variable-angle spectroscopic ellipsometry in the photon energy range from 0.75 to 4.5 eV. Between 0.75 and 3.3 eV the experimental data are fitted with a critical-point parametric model. The energies of E0, E0+Δ0, E1 and E1+Δ1 critical points are given for ZnSe and Zn0.87Mn0.13Se