The microstructural and electrical properties of solution-deposited GdCeOx dielectric thin films with different mixing ratios were studied. The Ce incorporation enhanced the degree of crystallization and the refractive index of the Gd2O3 film, reduced the hysteresis and increased the dielectric constant. According to reflective electron energy loss spectroscopy and X-ray photoelectron spectroscopy analyses, the bandgap of the GdCeOx film gradually decreased with increasing Ce/(Gd + Ce) atomic ratio, which was primarily affected by the reduction of the valence band offset. (C) 2012 Elsevier Ltd. All rights reserved.