Electronic band structure and optical properties of zinc monochalcogenides with zinc-blende- and wurtzite-type structures were studied using the ab initio density functional method within the LDA, GGA, and LDA+U approaches. Calculations of the optical spectra have been performed for the energy range 0-20 eV, with and without including spin-orbit coupling. Reflectivity, absorption and extinction coefficients, and refractive index have been computed from the imaginary part of the dielectric function using the Kramers--Kronig transformations. A rigid shift of the calculated optical spectra is found to provide a good first approximation to reproduce experimental observations for almost all the zinc monochalcogenide phases considered. By inspection of the calculated and experimentally determined band-gap values for the zinc monochalcogenide series, the band gap of ZnO with zinc-blende structure has been estimated.
@article{arxiv.0705.2550,
title = {Electronic structure and optical properties of ZnX (X=O, S, Se, Te)},
author = {S. Zh. Karazhanov and P. Ravindran and A. Kjekshus and H. Fjellvag and B. G. Svensson},
journal= {arXiv preprint arXiv:0705.2550},
year = {2009}
}