Ab-initio density functional study of defect-free and defective CdO

Ab-initio density functional calculation of the structural, electronic, dynamical and dielectric properties of CdO has been performed. The effect of the oxygen substitution by fluorine and vacancy formation on the lattice constant has also been investigated. In the first case the lattice constant increases whereas in the second one, a decrease is observed. This result is in good agreement with the experimental results. The DFT band gap decrease with the increase of the lattice constant indicating that the experimentally observed increase of the band gap when doping with fluorine is related with the Burstein-Moss effect rather than with the lattice constant change.