Effect of Gold Doping on the Structural, Electrical and Volatile Sensitivity of Spray Pyrolysis ZnO Thin Films

Sprayed ZnO thin film doped with 0–5 at% Au were prepared by pneumatic spray pyrolysis using zinc acetate dihydrate and HAuCl₄ as precursors dissolved in a mixture of water and methanol 3:1. In this work structural analyses by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and conductometric analyses were utilized in order to study the properties of the prepared films. Sensing responses for CH₃COCH₃ (acetone) and C₂H₅OH (ethanol) (5–200 ppm) were studied at 200 °C in a dry Ar environment. In addition, both ZnO film doped with 2% and 5% Au showed the highest sensitivity and fastest response times. The sensitivity increased and the response time decreased with increasing ethanol and acetone concentration while it was shown that both sensitivity and response time were better in the case of ethanol compared to acetone.