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 (ZrO(2)) is studied. The ZrO(2) cell volume linearly increases with the increasing Ce doping concentration. The intrinsic band gap of ZrO(2) of 5.70 eV reduces to 4.67 eV with the 2.08% Ce doping. In 4.16% cerium doped ZrO(2), the valence band maximum and conduction band minimum come closer to each other, about 1.1 eV, compared to ZrO(2). The maximum band gap reduction of ZrO(2) 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 ZrO(2) 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 ZrO(2) modeled system reduces the intensities of peaks in the optical spectra while keeping the peaks of intrinsic ZrO(2). However, the intrinsic peaks related to ZrO(2) completely vanish in 4.16%, 6.25%, 8.33%, and 12.5% Ce doped ZrO(2), and a new absorption hump is created.