Effect of Al- or Ga-additive on ionic conductivity of thin-film Gd-doped ceria

•Ionic conductivity of GDC thin film was enhanced by 1 mol% addition of Ga2O3 and Al2O3.•Additives are effective at reducing the activation energies of thin film.•Thin film GDC-1Ga shows its conductivity to be as high as that of pellet GDC and those of other highly-textured GDC thin films

For acceptor-doped ceria, thin films have usually shown lower ionic conductivity compared to the bulk. In this communication, the effect of additives (1 mol% of Ga2O3 or Al2O3) has been studied in terms of the film quality and the magnitude of the ionic conductivity of Gd-doped ceria (GDC). With additives, the films show strong (111)-orientation and the increased magnitude of ionic conductivity. The GDC film with the addition of 1 mol% Ga2O3 shows the highest conductivity among films and the conductivity is comparable to that of bulk samples. This proves that Ga and Al additives are useful to densify the film and that they reduce the grain-boundary resistivity of the thin films of acceptor-doped ceria.