Formulation and Characterization of Cu Doped ZnO Thick Films as LPG Gas Sensor

Abstract

Thick films of pure and various concentrations (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. % and 10 wt. %) of Cu-doped ZnO were prepared on alumina substrates using a screen printing technique. These films were fired at a temperature of 700ºC for two hours in an air atmosphere. Morphological, compositional and structural properties of the samples were obtained using the scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDAX) and X-ray diffraction techniques respectively. The LPG gas sensing properties of these thick films were investigated at different operating temperatures and LPG gas concentrations. The surface resistance of thick films decreases when exposed to LPG gas. The Cu doped films show significant sensitivity to LPG gas than pure ZnO film. 5 wt. % Cu-doped ZnO film was found to be more sensitive (87.3 %) to LPG gas exposed at 300 oC than other doping concentrations with fast response and recovery time.

Keywords

• ZnO
• Cu
• Thick films
• Screen printing
• LPG