Ethanol sensing properties of spray pyrolyzed ZnFe₂O₄ thin films

A spinel crystal structure of ZnFe₂O₄ was synthesized by using the spray pyrolysis method. A pure phase ZnFe₂O₄ was obtained at a relatively lower temperature of 400°C. The gas sensing properties of the ZnFe₂O₄ films with different volume % of Zn and Fe were measured at different temperatures. The maximum ethanol gas response of 849 at the operation temperature of 350°C was found for the ZnFe₂O₄ film. The annealed ZnFe₂O₄ thin films exhibited good sensitivity and rapid responserecovery characteristics to ethanol. Further, it has been shown the gas response of the ZnFe₂O₄ gas sensor depends upon different volume % of Zn and Fe. This superior performance is attributed to the larger surface area, the uniform and well-dispersed deposition of the particles over the surface, and the large band gap of the chemically-prepared spinel ferrite.