Effect of the ceria dopant on the structural and dielectric properties of ZnO semiconductors

Abstract ZnO doped with different concentrations (2, 4, 6, 8 and 10%) of ceria was synthesized by the conventional solid–state reaction method. X-ray diffraction spectra confirm that all the samples have a hexagonal structure. The structural properties of the samples were studied from X-ray diffraction data. The surface morphology and elemental composition of the ceria doped ZnO samples were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. The variation of the dielectric constant, the dielectric loss and the ac conductivity as functions of frequency in the range of 100 Hz–1 MHz for the as-prepared material were studied at room temperature by using impedance spectroscopy. All the samples exhibit a normal dielectric dispersion behavior, i.e. it decreases with increasing frequency due to the Maxwell–Wagner type of interfacial polarization. The ac conductivity data was used to evaluate the maximum barrier height, the minimum hoping distance, and the density of localized states at Fermi level.