Defect and mixed conductivity in nanocrystalline doped cerium oxide

The results obtained from a study on the microstructure and the electrical properties of Gd-doped CeO2 thin films were reported. Dense, nanocrystalline films on sapphire substrates are prepared using a polymeric precursor spin coating technique. The electrical conductivity was studied as a function of temperature and oxygen activity and correlated with the grain size. For nanocrystalline Gd-doped CeO2 thin films, the ionic conductivity increased with decreasing activation energy as the grain size decreased. A conductivity model was developed to analyze PO2 behavior of the electrical conductivity. Using the conductivity model, the hopping energy of electron conduction and the enthalpy of oxygen vacancy formation were determined for different microstructures.