Structural, Electronic and Gas Sensing Properties of Cu-Doped ZrO2-TiO2 | ||
| Iraqi Journal of Applied Physics | ||
| Article 1, Volume 10, Issue 3, September 2014, Pages 23-28 | ||
| Authors | ||
| Muthafar F. Al-Hilli; Haidar J. Abdul-Ameer; Raad M. S. Al-Haddad | ||
| Abstract | ||
| The study of ZrO2-TiO2 doped with Cu is motivated by its applications as a solid state gas sensor material. Cu2x(Zr0.5Ti0.5)2-xO4 ceramic system was prepared with (x=0,0.2,0.4,0.6,0.8) by using standard chemical solid reaction technique. The X-ray diffraction studies reveal the formation of orthorhombic phase with the space group Pbcn. The crystallite size was found to decrease with Cu2+ ion addition. The lattice parameters a, b and c were calculated. The charge carrier concentration increased with Cu2+ addition and charge mobility increased with Cu2+ ion content till x=0.4. Conduction mechanism was noticed to change from n-type to p-type at x=0.6. The DC conductivity increased with Cu2+ content up to x=0.6 and then decreased at x=0.8. The conduction mechanism in CuO/ZrO2/TiO2 system is due to oxygen-ion conduction and hopping of charge carriers. AC resistivity decreased with frequency and increased with Cu2+ additions. The dielectric constant decreased with frequency and increased with Cu2+ content. The decrease in dielectric loss tangent with frequency agrees well with Deby’s type relaxation process. The dielectric loss tangent did not change significantly with Cu2+ addition up to x=0.6 but increased slightly at x=0.8. The samples with x= 0.4 and 0.8 were selected to measure CO2 gas sensing at room temperature. The sample with x=0.4 showed stable and higher sensitivity at both CO2 gas exposure and evacuation. The active region of sensitivity of the bulk sensor was reached after 30 s of exposure to CO2 gas. The sample with x=0.8 was selected to measure NO2 gas sensing at room temperature. It showed relatively lower sensitivity for NO2 gas than that of CO2 gas. | ||
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