Effect of Sn2O3 doping on structural, optical and dielectric properties of ZnO ceramics

• The effects of different Sn2O3 doping concentrations were investigated.
• Band gap broadens if the doping concentration increases.
• The increase in Sn2O3 content, superior or equal to 10 wt%, the dielectric loss disappears.
• The dc conductivity increases with the increase of Sn2O3 doping concentrations.
• The temperature dependent ac conductivity follows the universal power law.

The synthesis of the undoped ZnO and ZnO–Sn2O3 composites prepared by conventional solid-state reaction method has been reported. Besides, the effect of increasing Sn2O3 content from 5 to 15 wt% on structural, optical, dielectric and electrical properties of the ZnO–Sn2O3 composites has also been investigated. In fact, the X-ray diffraction analysis indicates that the as-prepared ZnO–Sn2O3 composites may contain some combined phases such as SnO and Zn2SnO4. The atomic force microscopy shows that the surfaces of the composites are rough. The band gap energy seems to depend on the amount of Sn2O3 addition, with the maximum obtained at 15 wt% Sn2O3. Concerning the optical band gap, it has been found to be in the range of 3.18–3.93 eV. The dielectric loss was found to decrease with the increase in frequency. The results obtained from the ac-conductivity revealed that the values of σ(ω) increases with the Sn2O3 adding content. The dc-conductivity of all the composites increases with the increase in temperature. The electrical conductivity was analyzed with the power law, and agrees with the correlation barrier hopping model.