In this study, ZnSe(1-x)O(x) layers with oxygen contents of up to 7.0% are successfully grown at 300 degrees C on semi-insulating GaAs substrates by molecular beam epitaxy. The deposited ZnSe(1-x)O(x) films are characterized by Raman spectroscopy and the optical properties studied by spectroscopic ellipsometry. We examine the complex dielectric function obtained by spectroscopic ellipsometry in the photon range from 1.5 to 5 eV. The shifting and broadening of the critical points in the ZnSe(1-x)O(x) epilayers as a function of the O composition are investigated for the first time. The characteristics of the peaks change as the O composition increases. The second derivative of the dielectric function is presented and analyzed. The dielectric function spectra reveal distinct structures which can be attributed to the band gap and optical transitions at higher energy. (C) 2010 American Institute of Physics. [doi:10.1063/1.3511439]
