Electronic Band Structure Variations in the Ceria Doped Zirconia: A First Principles Study.

Using first principle calculations, the effect of Ce with different doping concentrations in the network of Zirconium dioxide (ZrO₂) is studied. The ZrO₂ cell volume linearly increases with the increasing Ce doping concentration. The intrinsic band gap of ZrO₂ of 5.70 eV reduces to 4.67 eV with the 2.08% Ce doping. In 4.16% cerium doped ZrO₂, the valence band maximum and conduction band minimum come closer to each other, about 1.1 eV, compared to ZrO₂. The maximum band gap reduction of ZrO₂ is observed at 6.25% Ce doping concentration, having the value of 4.38 eV. No considerable shift in the band structure is found with further increase in the doping level. The photo-response of the ZrO₂ is modulated with Ce insertion, and two distinct modifications are observed in the absorption coefficient: an imaginary part of the dielectric function and conductivity. A 2.08% Ce-doped ZrO₂ modeled system reduces the intensities of peaks in the optical spectra while keeping the peaks of intrinsic ZrO₂. However, the intrinsic peaks related to ZrO₂ completely vanish in 4.16%, 6.25%, 8.33%, and 12.5% Ce doped ZrO₂, and a new absorption hump is created.