Spectroscopic ellipsometric characterization of undoped ZnTe films grown on GaAs

We report highly accurate dielectric function data for ZnTe. These data were made possible by the high quality of the heteroepitaxial material and the development of a chemical etching procedure for producing abrupt surfaces on ZnTe; they provided the first observation of the $E_0{\mathrm{+\Delta }}_0$ structure in ZnTe by spectroscopic ellipsometry and evidence for several contributions to the $E_2$ structure. Accurate critical point energies were obtained by Fourier analysis.