Electronic structure of Co doped ZnO: Theory and experiment

We have studied the electronic structure of Co doped ZnO by theory and experiment. Photoelectron and x-ray absorption spectroscopy experiments were performed on 5% Co doped ZnO thin films. The results show that Co - 3 d states lie in the valence band and hybridize considerably with O - 2 p states. These results compare qualitatively with our density functional calculations combined with a Hubbard approach to include strong electron correlations within the Co - 3 d state.