The preparation and characterization of Cd(OH)2 gas sensor sensitive to CO gas

Cd(OH)2 thin films were successfully grown on glass substrates by SILAR method at room temperature. The effect of SILAR cycle on the structural, morphological, compositional and CO gas sensing propertiesof the thin films were investigated by XRD, SEM, EDAX and gas measurement system, respectively. The XRD and SEM studies indicated that Cd(OH)2 thin films had polycrystalline nature with hexagonal phase of Cd(OH)2 and the structural and morphological properties of the thin films depended on the SILAR cycle.CO gas sensing measurements were carried out as a function of temperature and gas concentrations. The sensing responses of the thin film sensors increased with operating temperature and reached to the maximum at 157 °C. The Cd(OH)2 thin film sensors exhibited high sensing responses when exposed to CO gas concentration in the range of 50-500 ppm at operating temperature of 157 °C. At the optimal operating temperature (157 °C) and 50 ppm CO gas concentration, the sensing responses of Cd(OH)2 thin film sensors with 30, 40 and 50 SILAR cycle were calculated to be 24%, 40% and 26 %, respectively. It was seen that the gas sensing properties of the thin film with 40 SILAR cycle were better than others.