Studies on structural and electrical properties of ZnO/TiO2 composite materials

The synthesis of the ZnO/TiO2 composites prepared by conventional solid-state reaction has been reported. The structural properties of the pellets have been investigated by X-ray diffraction and their dielectric spectra were measured in the frequency range from 0.1 Hz to 10 MHz and temperature range from 0 degrees C to 200 degrees C. XRD patterns have revealed the presence of three crystalline phases of the ZnO, Zn2TiO4 (cubic) and ZnTiO3 (hexagonal) compounds. Grain sizes were obtained in the range of 73-87 nm. It also exhibits a decrease of grain sizes and an increase of residual stress with the increase of TiO2 content from 1 wt% to 7 wt%. When the temperature is increased, the dc conductivity and the activation energies were found to be in the range of 10(-9) - 10(-5) S/cm and 0.13-1.19 eV, respectively. The alternating current (ac) conductivity was well represented by the power law A omega(s). The electric conduction was dominant by the correlated barrier hopping (CBH) model. The electron barrier height, W-M, varies greatly on the content of TiO2 where their values were found to be temperature- and frequency-dependent for all ZnO/TiO2 composites. (C) 2015 Elsevier B.V. All rights reserved.